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  • 1.
    Agrios, Alexander George
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Cesar, I.
    Comte, P.
    Nazeeruddin, M. K.
    Grätzel, M.
    Nanostructured composite films for dye-sensitized solar cells by electrostatic layer-by-layer deposition2006In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 18, no 23, p. 5395-5397Article in journal (Refereed)
    Abstract [en]

    The possibilities for making nanocomposite semiconductor films for DSC using the ELBL method was investigated. Coated slides were cut in half vertically giving two strips that can be subjected to different treatments for comparison. The electrode was heated to 450 °C for 30 min and then Cooled to 80 °C. Scanning electron microscopy of a sintered film with 5 cycles of TiO2 nanoparticles shows that the particles are well distributed and completely cover the transparent conducting oxide substrate. Spectroscopic measurements of a dye-coated film in acetonitrile found a dye concentration within the film of 0.15 mM based on an extinction coefficient. The solar cell including a scattering layer had more than double the current of the transparent layer-only cell. It was observed that ELBL method can produce TiO2 films for DSC with high efficiencies at low thickness.

  • 2.
    Andersson, Samir
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zou, Dapeng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Rong
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Shiguo
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Åkermark, Björn
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Selective Positioning of CB 8 on Two Linked Viologens and Electrochemically Driven Movement of the Host Molecule2009In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 8, p. 1163-1172Article in journal (Refereed)
    Abstract [en]

    The binding interactions between cucurbit[8]uril (CB[8]) and a dicationic guest N,N-dimethyl-3,3'-dimethyl-4,4'-bipyridinium (DMV2+) have been investigated by various experimental techniques including NMR, ESI-MS, and UV/Vis and fluorescence spectroscopy. In a three-component system consisting of CB[81, N,N-dimethyl-4,4'-bipyridinium (MV2+) and DMV2+, CB[8] was found to exhibit a higher binding affinity to DMV2+ than to MV2+, When DMV2+ was connected to MV2+ by an alkyl chain, the first equiv. of CB[8] could be selectively positioned on the DMV2+ moiety, and then a second equiv. of CB[8] was positioned on the MV2+ moiety. Spectroelectrochemical studies showed that upon the reduction of this system at -0.6 V vs. AgCl, the CB[8] could move from the DMV2+ moiety to the MV+center dot radical, which formed a dimer inside the CB[8] cavity. Molecular oxygen quenched the dimer, and the CB[8] moved back to the DMV2+ moiety, indicating it molecular movement driven by electrochemistry. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

  • 3.
    Bhagavathiachari, Muthuraaman
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Elumalai, V.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Polymer-doped molten salt mixtures as a new concept for electrolyte systems in dye-sensitized solar cells2017In: ACS Omega, ISSN 2470-1343, Vol. 2, no 10, p. 6570-6575Article in journal (Refereed)
    Abstract [en]

    A conceptually new polymer electrolyte for dye-sensitized solar cells is reported and investigated. The benefits of using this type of electrolyte based on ionic liquid mixtures (ILMs) and room temperature ionic liquids are highlighted. Impedance spectroscopy and transient electron measurements have been used to elucidate the background of the photovoltaic performance. Even though larger recombination losses were noted, the high ion mobility and conductivity induced in the ILMs by the added polymer result in enhanced overall conversion efficiencies.

  • 4.
    Bhagavathiachari, Muthuraaman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Elumalai, Viswanathan
    Vlachopoulos, Nick
    Safdari, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Gardner, James M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    A quasi-liquid polymer-based cobalt redox mediator electrolyte for dye-sensitized solar cells2013In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 40, p. 17419-17425Article in journal (Refereed)
    Abstract [en]

    Recently, cobalt redox electrolyte mediators have emerged as a promising alternative to the commonly used iodide/triiodide redox shuttle in dye-sensitized solar cells (DSCs). Here, we report the successful use of a new quasi-liquid, polymer-based electrolyte containing the Co3+/Co2+ redox mediator in 3-methoxy propionitrile solvent in order to overcome the limitations of high cell resistance, low diffusion coefficient and rapid recombination losses. The performance of the solar cells containing the polymer based electrolytes increased by a factor of 1.2 with respect to an analogous electrolyte without the polymer. The performances of the fabricated DSCs have been investigated in detail by photovoltaic, transient electron measurements, EIS, Raman and UV-vis spectroscopy. This approach offers an effective way to make high-performance and long-lasting DSCs.

  • 5. Bi, D.
    et al.
    Xu, Bo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Dalian University of Technology (DUT), China.
    Gao, P.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Dalian University of Technology (DUT), China.
    Grätzel, M.
    Hagfeldt, A.
    Facile synthesized organic hole transporting material for perovskite solar cell with efficiency of 19.8%2016In: Nano Energy, ISSN 2211-2855, Vol. 23, p. 138-144Article in journal (Refereed)
    Abstract [en]

    The exploration of alternative molecular hole-transporting materials (HTMs) specifically for high performance perovskite solar cells (PSCs) is a relatively recent research area. Aiming for further increasing the 'efficiency-cost ratio' of PSCs, we developed a spiro[fluorene-9,9'-xanthene] based HTM (X59) via two-step synthesis from commercial precursors for perovskite solar cells (PSCs) that works as effectively as the well-known HTM-Spiro-OMeTAD-based device under the same conditions. The molecular structure was analyzed by X-ray crystallography indicating a similar packing regime as for Spiro-OMeTAD. An impressive PCE of 19.8% was achieved by using X59 as HTM in PSC, which can compete with the record PCE of 20.8% by using the state-of-the-art-HTM Spiro-OMeTAD (Tress et al., 2016) [1]. The optimized devices employing X59 as HTM exhibited minimized hysteresis, excellent reproducibility and reasonable stability under dark and dry conditions. The present finding highlights the potential of spiro-type HTM for high performance PSCs and paves the way to a much deceased fabrication cost for potential commercialization of perovskite solar panels.

  • 6.
    Boschloo, Gerrit K.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Edvinsson, Tomas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Dye-Sensitized Nanostructured ZnO Electrodes for Solar Cell Applications2006In: Nanostructured Materials for Solar Energy Conversion, Elsevier, 2006, p. 227-254Chapter in book (Other academic)
    Abstract [en]

    This chapter describes dye-sensitized nanostructured ZnO electrodes for solar cell applications. Dye-sensitized nanostructured solar cells (DNSCs) based on nanostructured metal oxide films have attracted much attention in recent years. This chapter explains the schematic representation of the DNSC. The performance of dye-sensitized ZnO solar cells in terms of solar-to-electrical energy conversion efficiencies is so far significantly lower than that of TiO2, reaching currently about 4-5%. An analysis of the energetics and kinetics of ZnO-based DNSCs suggests that this is mainly because of the lesser degree of optimization in case of ZnO compared to TiO2-based DNSCs. A large potential exists to improve on the performance of dye-sensitized ZnO solar cells by learning how to use new types of anchoring groups and controlling the chemistry at the oxide/dye/electrolyte interface. This, in combination with the possibilities to tailor-make ZnO materials, manifests the opportunities for future research and development of these devices.

  • 7. Cappel, U. B.
    et al.
    Gibson, E. A.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Uppsala University, Sweden.
    Boschloo, G.
    Dye regeneration by Spiro-MeOTAD in solid state dye-sensitized solar cells studied by photoinduced absorption spectroscopy and spectroelectrochemistry2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 15, p. 6275-6281Article in journal (Refereed)
    Abstract [en]

    Photoinduced absorption (PIA) spectroscopy is presented as a tool for the systematic study of dye regeneration and pore filling in solid state dye-sensitized solar cells (DSC). Oxidation potentials and extinction coefficients for oxidized species of the perylene dye, ID28, on TiO(2) and of the hole conductor, 2,2'7,7'-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene (spiro-MeOTAD), were determined by spectroelectrochemistry. The onset of oxidation of a solid film of spiro-MeOTAD was found to be 0.15 V versus Fc/Fc(+) and extinction coefficients of spiro-MeOTAD(+) were found to be 33 000 M(-1) cm(-1) at 507 nm and 8500 M(-1) cm-' at 690 nm. Electrons in TiO(2) films were shown to alter the ground-state absorption spectra of ID28 attached to TiO(2)-PIA measurements indicated a good contact between ID28 and spiro-MeOTAD for different spiro-MeOTAD concentrations for both 2- and 6-mu m thick TiO(2) films. We discuss the possibility of estimating the quality of pore filling from the positions of absorption peaks. Results suggested that with a spiro-MeOTAD concentration of 300 mg mL(-1) in chlorobenzene, a uniform distribution of spiro-MeOTAD in the pores of the 6-mu m thick TiO(2) film could be achieved.

  • 8. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Degradation of Cyanoacrylic Acid-Based Organic Sensitizers in Dye-Sensitized Solar Cells2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 7, p. 1270-1275Article in journal (Refereed)
    Abstract [en]

    Organic dyes have become widely used in dye-sensitized solar cells (DSSCs) because of their good performance, flexible structural modifications, and low costs. To increase the photostability of organic dye-based DSSCs, we conducted a full study on the degradation mechanism of cyanoacrylic acid-based organic sensitizers in DSSCs. The results showed that with the synergy between water and UV light, the sensitizer could desorb from the TiO2 surface and the cyanoacrylic acid unit of the sensitizer was transformed into the aldehyde group. It was also observed that the water content had a great effect on the degradation process. Our experiments conducted using O-18-labeled water demonstrated that the oxygen atom of the aldehyde group identified in the degraded dye came from the solvent water in the DSSCs. Therefore, controlling the water content during DSSC fabrication, good sealing of cells, and filtering the UV light are crucial to produce DSSCs that are more durable and robust.

  • 9. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Efficient Panchromatic Organic Sensitizers with Dihydrothiazole Derivative as pi-Bridge for Dye-Sensitized Solar Cells2013In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, no 21, p. 10960-10965Article in journal (Refereed)
    Abstract [en]

    Novel organic dyes CC201 and CC202 with dihydrothiazole derivative as pi-bridge have been synthesizedand applied in the DSSCs. With the synergy electron-withdrawing of dihydrothiazole and cyanoacrylic acid, these two novel dyes CC201 and CC202 show excellent response in the region of 500-800 nm. An efficiency as high as 6.1% was obtained for the device fabricated by sensitizer CC202 together with cobalt electrolyte under standard light illumination (AM 1.5G, 100 mW cm(-2)). These two novel D-pi-A panchromatic organic dyes gave relatively high efficiencies except common reported squaraine dyes.

  • 10. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Highly efficient organic dyes containing a benzopyran ring as a pi-bridge for DSSCs2013In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, no 31, p. 12688-12693Article in journal (Refereed)
    Abstract [en]

    A series of novel organic dyes containing a benzopyran ring as a p-bridge have been designed and applied in dye-sensitized solar cells (DSSCs). This series of dyes show the excellent DSSCs' performance, due to their efficient light-to-photocurrent conversion in the region from 380 nm to 600 nm, with the highest IPCE values exceeding 90%. Through modification of the donor units, an efficiency as high as 7.5% has been achieved under standard light illumination (AM 1.5G, 100 mW cm(-2)) by the dye CC103.

  • 11. Chen, H.
    et al.
    Gao, Y.
    Lu, Z.
    Ye, L.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian 116024, China.
    Copper Oxide Film In-situ Electrodeposited from Cu(II) Complex as Highly Efficient Catalyst for Water Oxidation2017In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 230, p. 501-507Article in journal (Refereed)
    Abstract [en]

    Water splitting is deemed as an effective pathway for producing ideal clean energy, such as hydrogen. Here, a copper oxide film (Cu-Tris film) was prepared in-situ from a 0.2 M phosphate buffer solution (pH = 12.0) containing 1.0 mM Cu2+ and 2.0 mM Tris via controlled-potential electrodeposition. The Cu-Tris film showed a significantly low overpotential of 390 mV at a current density of 1.0 mA/cm2 for electrocatalytic water oxidation. Simultaneously, a considerably low Tafel slope of 41 mV/decade was achieved. This Cu-Tris film also exhibited a high and stable current density of ca. 7.5 mA/cm2 at 1.15 V vs. NHE for long-term electrocatalysis (10 h). These results demonstrated the superior performance of the developed Cu-Tris film, which should be attributed to the regulating effect of the five coordinated planar structure of the Cu-Tris complex precursor during the process of electrodeposition.

  • 12. Chen, Hong
    et al.
    Zhao, Huishuang
    Yu, Zheng-Bao
    Wang, Lei
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    Sun, Junliang
    Construct Polyoxometalate Frameworks through Covalent Bonds2015In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 54, no 17, p. 8699-8704Article in journal (Refereed)
    Abstract [en]

    An emerging strategy for exploring the application of polyoxometalates (POMs) is to assemble POM clusters into open-framework materials, especially inorganic organic hybrid three-dimensional (3D) open-framework materials, via the introduction of different organic linkers between the POM clusters. This strategy has yielded a few 3D crystalline POMs of which a typical class is the group of polyoxometalate metal organic frameworks (POMMOFs). However, for reported POMMOFs, only coordination bonds are involved between the linkers and POM clusters, and it has not yet produced any covalently bonded polyoxometalate frameworks. Here, the concept of "covalently bonded POMs (CPOMs)" is developed. By using vanadoborates as an example, we showed that the 3D CPOMs can be obtained by a condensation reaction through the oxolation mechanism of polymer chemistry. In particular, suitable single crystals were harvested and characterized by single-crystal X-ray diffraction. This work forges a link among polymer science, POM chemistry, and open-framework materials by demonstrating that it is possible to use covalent bonds according to polymer chemistry principles to construct crystalline 3D open-framework POM materials.

  • 13. Chen, Lin
    et al.
    Wang, Mei
    Han, Kai
    Zhang, Peili
    Gloaguen, Frederic
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    A super-efficient cobalt catalyst for electrochemical hydrogen production from neutral water with 80 mV overpotential2014In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 7, no 1, p. 329-334Article in journal (Refereed)
    Abstract [en]

    Self-assembled molecular iron and cobalt catalysts (MP4N2, M = Fe, Co) bearing a multihydroxy-functionalized tetraphosphine ligand electrocatalyze H-2 generation from neutral water on a mercury electrode at -1.03 and -0.50 V vs. NHE, respectively. Complex CoP4N2 displays extremely low overpotential (E-onset = 80 mV) while maintaining high activity and good stability. Bulk electrolysis of CoP4N2 in a neutral phosphate buffer solution at -1.0 V vs. NHE produced 9.24 x 10(4) mol H-2 per mol cat. over 20 h, with a Faradaic efficiency close to 100% and without apparent deactivation.

  • 14. Cheng, M.
    et al.
    Yang, X.
    Li, J.
    Zhang, F.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Co-sensitization of organic dyes for efficient dye-sensitized solar cells2013In: ChemSusChem, ISSN 1864-5631, Vol. 6, no 1, p. 70-77Article in journal (Refereed)
    Abstract [en]

    Novel cyanine dyes, in which a tetrahydroquinoline derivative is used as an electron donor and 1-butyl-5-carboxy-3, 3-dimethyl-indol-1-ium moiety is used as an electron acceptor and anchoring group, were designed and synthesized for application in dye-sensitized solar cells. The photovoltaic performance of these solar cells depends markedly on the molecular structure of the dyes in terms of the n-hexyl chains and the methoxyl unit. Retardation of charge recombination caused by the introduction of n-hexyl chains resulted in an increase in electron lifetime. As a consequence, an improvement of open-circuit photovoltage (V oc) was achieved. Also, the electron injection efficiencies were improved by the introduction of methoxyl moiety, which led to a higher short-circuit photocurrent density (Jsc). The highest average efficiency of the sensitized devices (η) was 5.6 % (Jsc=13.3 mA cm-2, Voc=606 mV, and fill factor FF=69.1 %) under 100 mW cm-2 (AM 1.5G) solar irradiation. All of these dyes have very high absorption extinction coefficients and strong absorption in a relatively narrow spectrum range (500-650 nm), so one of our organic dyes was explored as a sensitizer in co-sensitized solar cells in combination with the other two other existing organic dyes. Interestingly, a considerably improved photovoltaic performance of 8.2 % (Jsc=20.1 mA cm-2, Voc=597 mV, and FF=68.3 %) was achieved and the device showed a panchromatic response with a high incident photon-to-current conversion efficiency exceeding 85 % in the range of 400-700 nm. Sensitive dyes absorb it all: Co-sensitization of three spectrally complementary dyes on a TiO2 film in a well-designed sequence significantly improves the photovoltaic performance of the device, and an efficiency of 8.2 % is achieved. The devices demonstrate a panchromatic response with an incident photon-to-current conversion efficiency >80 % over the entire visible spectral region from 400 to 700 nm.

  • 15.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Li, Yuanyuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Safdari, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Chen, Cheng
    Liu, Peng
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Efficient Perovskite Solar Cells Based on a Solution Processable Nickel(II) Phthalocyanine and Vanadium Oxide Integrated Hole Transport Layer2017In: Advanced Energy Materials, ISSN 1614-6832, Vol. 7, no 14, article id 1602556Article in journal (Refereed)
    Abstract [en]

    An organic-inorganic integrated hole transport layer (HTL) composed of the solution-processable nickel phthalocyanine (NiPc) abbreviated NiPc-(OBu)(8) and vanadium(V) oxide (V2O5) is successfully incorporated into structured mesoporous perovskite solar cells (PSCs). The optimized PSCs show the highest stabilized power conversion efficiency of up to 16.8% and good stability under dark ambient conditions. These results highlight the potential application of organic-inorganic integrated HTLs in PSCs.

  • 16.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Xu, Bo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Chen, C.
    Yang, X.
    Zhang, F.
    Tan, Q.
    Hua, Yong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Phenoxazine-based small molecule material for efficient perovskite solar cells and bulk heterojunction organic solar cells2015In: Advanced Energy Materials, ISSN 1614-6832, Vol. 5, no 8, article id 1401720Article in journal (Refereed)
    Abstract [en]

    The phenoxazine-based acceptor-donor-acceptor structured small-molecule material M1 is used either as a hole-transport material in (CH<inf>3</inf>NH<inf>3</inf>)PbI<inf>3</inf>-perovskite-based solar cells or as photoactive donor material in bulk heterojunction organic solar cells. Excellent power conversion efficiencies of 13.2% and 6.9% are achieved in these two types of photovoltaic devices, respectively.

  • 17. Cheng, Ming
    et al.
    Yang, Xichuan
    Chen, Cheng
    Tan, Qin
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Molecular engineering of small molecules donor materials based on phenoxazine core unit for solution-processed organic solar cells2014In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 27, p. 10465-10469Article in journal (Refereed)
    Abstract [en]

    A D-pi-A type small molecule POZ4 and a A-pi-D-pi-A type small molecule POZ6, in which phenoxazine was used as the central building block and dicyanovinyl was employed as the electron-withdrawing end-group, have been designed and synthesized. Compared with D-pi-A type donor material POZ4, the donor material POZ6 with A-pi-D-pi-A configuration shows much wider response to solar light. An efficiency of 5.60% was obtained for the POZ6: PC71BM based solar cells, and the device fabricated with POZ6:PC71BM (1 : 1) showed a much better balanced hole and electron mobility of 2.24 x 10(-4) cm(2) V-1 s(-1) and 3.17 x 10(-4) cm(2) V-1 s(-1), respectively.

  • 18. Cheng, Ming
    et al.
    Yang, Xichuan
    Chen, Cheng
    Zhao, Jianghua
    Tan, Qin
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Effect of the acceptor on the performance of dye-sensitized solar cells2013In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 40, p. 17452-17459Article in journal (Refereed)
    Abstract [en]

    Three new phenothiazine dyes were designed and synthesized, utilizing different acceptor groups. Upon application to TiO2-based solar cells, the effects of different acceptors on the photophysical and electrochemical properties of the dyes and the solar cell performance are detailed. The introduction of a pyridinium unit or 5-carboxy-1-hexyl-2,3,3-trimethyl-indolium unit into the molecular frame as the acceptor instead of cyano acrylic acid can effectively cause a red shift in the absorption spectra. Applied to DSSCs, the devices sensitized by CM502 with the pyridinium unit as the acceptor show the highest efficiency of 7.3%. The devices fabricated with dye CM501 with cyano acrylic acid as the acceptor exhibited the highest V-oc while for the devices sensitized by the dye CM503 with 5-carboxy-1-hexyl2,3,3- trimethyl-3H-indolium unit as the acceptor, the Voc value was the lowest, at 494 mV. The addition of TBP in the electrolyte can improve the performance of DSSCs fabricated using CM501 and CM502, with the Voc value greatly improved but the J(sc) value slightly decreased. However, with the addition of TBP in the electrolyte, the efficiency of the cells sensitized by CM503 dropped significantly (from 4.9% to 1.0% when 0.1 M TBP was added).

  • 19. Cheng, Ming
    et al.
    Yang, Xichuan
    Zhao, Jianghua
    Chen, Cheng
    Tan, Qin
    Zhang, Fuguo
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Efficient Organic Dye-Sensitized Solar Cells: Molecular Engineering of Donor-Acceptor-Acceptor cationic dyes2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 12, p. 2322-2329Article in journal (Refereed)
    Abstract [en]

    Three metal-free donor-acceptor-acceptor sensitizers with ionized pyridine and a reference dye were synthesized, and a detailed investigation of the relationship between the dye structure and the photophysical and photoelectrochemical properties and the performance of dye-sensitized solar cells (DSSCs) is described. The ionization of pyridine results in a red shift of the absorption spectrum in comparison to that of the reference dye. This is mainly attributable to the ionization of pyridine increasing the electron-withdrawing ability of the total acceptor part. Incorporation of the strong electron-withdrawing units of pyridinium and cyano acrylic acid gives rise to optimized energy levels, resulting in a large response range of wavelengths. When attached to TiO2 film, the conduction band of TiO2 is negatively shifted to a different extent depending on the dye. This is attributed to the electron recombination rate between the TiO2 film and the electrolyte being efficiently suppressed by the introduction of long alkyl chains and thiophene units. DSSCs assembled using these dyes show efficiencies as high as 8.8%.

  • 20. Cheng, Minglun
    et al.
    Wang, Mei
    Zheng, Dehua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Effect of the S-to-S bridge on the redox properties and H-2 activation performance of diiron complexes related to the [FeFe]-hydrogenase active site2016In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, no 44, p. 17687-17696Article in journal (Refereed)
    Abstract [en]

    Three biomimetic models of the [FeFe]-hydrogenase active site, namely diiron dithiolates of [(mu-edt){Fe(CO)(3)}{Fe(CO)(kappa(2)-PNP)}] (1, edt = ethane-1,2-dithiolate, PNP = Ph2PCH2N(nPr)CH2PPh2), [(mu bdtMe){Fe(CO)(3)}{Fe(CO)(kappa(2)-PNP)}] (2, bdtMe = 4-methylbenzene-1,2-dithiolate), and [(mu-adtBn){Fe(CO)(3)} {Fe(CO)(kappa(2)-PNP)}] (3, adtBn = N-benzyl-2-azapropane-1,3-dithiolate), were prepared and structurally characterized. These complexes feature the same PNP ligand but different S-to-S bridges. Influence of the S-to-S bridge on the electrochemical properties and chemical oxidation reactivity of 1-3 was studied by cyclic voltammetry and by in situ IR spectroscopy. The results reveal that the S-to-S bridge has a considerable effect on the oxidation reactivity of 1-3 and on the stability of in situ generated single-electron oxidized complexes, [1](+), [2](+), and [3](+). The performances of [1](+) and [2](+) for H-2 activation were explored in the presence of a mild chemical oxidant, while rapid decomposition of [3](+) thwarted the further study of this complex. Gratifyingly, 1 was found to be catalytically active, although in a low turnover number, for H-2 oxidation in the presence of excess mild oxidant and a proton trapper under 1 atm H-2 at room temperature.

  • 21. Colodrero, Silvia
    et al.
    Mihi, Agustin
    Häggman, Leif
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Ocana, Manuel
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Miguez, Hernan
    Porous One-Dimensional Photonic Crystals Improve the Power-Conversion Efficiency of Dye-Sensitized Solar Cells2009In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 21, no 7, p. 764-+Article in journal (Refereed)
    Abstract [en]

    The solar-to-electric power-conversion efficiency (71) of dye-sensitized solar cells can be greatly enhanced by integrating a mesoporous, nanoparticle-based, 1D photonic crystal as a coherent scattering layer in the device. The photogenerated current is greatly improved without altering the open-circuit voltage of the cell, while keeping the transparency of the cell intact. Improved average 77 values between 15% and 30% are attained.

  • 22.
    Cong, Jiayan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hao, Yan
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Two Redox Couples are Better Than One: Improved Current and Fill Factor from Cobalt-Based Electrolytes in Dye-Sensitized Solar Cells2014In: Advanced Energy Materials, ISSN 1614-6832, Vol. 4, no 8, p. 1301273-Article in journal (Refereed)
    Abstract [en]

    A tandem redox strategy is used in cobalt-based electrolytes. Co(bpy) 3 2+/Co(bpy)3 3+ offers a high photovoltage at the photoanode, whereas the I-/I3 - or Fc/Fc+ redox couples facilitate charge transfer at the counter electrode. Electron exchange in the electrolyte offers beneficial concentration gradients. The overall conversion efficiency is improved from 6.5% to 7.5%.

  • 23. Cong, Jiayan
    et al.
    Yang, Xichuan
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Iodine/iodide-free redox shuttles for liquid electrolyte-based dye-sensitized solar cells2012In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 5, no 11, p. 9180-9194Article, review/survey (Refereed)
    Abstract [en]

    Dye-sensitized solar cells have attracted intense academic interest over the past two decades. For a long time, the development of new redox systems has fallen far behind that of the sensitizing dyes and other materials. However, the field has received renewed attention recently. In particular, in 2011, the Gratzel group published a record DSC efficiency of 12.3% by using a new Co-complex-based electrolyte. In this review, we will provide an overview of iodine/iodide-free redox systems for liquid electrolytes, and reveal that the design of an efficient redox system should combine with appropriate sensitizing dyes which is the pivotal challenge for highly efficient DSCs.

  • 24. Ding, Xin
    et al.
    Gao, Yan
    Zhang, Linlin
    Yu, Ze
    Liu, Jianhui
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Artificial photosynthesis: A two-electrode photoelectrochemical cell for light driven water oxidation with molecular components2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 149, p. 337-340Article in journal (Refereed)
    Abstract [en]

    An efficient two-electrode molecular PEC was assembled, in which a photoanode was constructed using a co-adsorbed method with a molecular photosensitizer (PS) 1 and a molecular catalyst 2 on TiO2-sintered FTO electrode (TiO2(1 + 2)). Without applied bias against a reference electrode, the system achieves remarkable photocurrent densities and carries out light driven water oxidation as evidenced by Clark electrode measurements in solution. A photocurrent density of 70 mA/cm(2) has been obtained within 10 s illumination time, and a TON of about 220 was obtained with a maximum turnover frequency (TOF) of ca. 4 min(-1) within the initial 5 minutes illumination duration.

  • 25.
    Duan, Lele
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Xu, Yunhua
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Pan
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Wang, Mei
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Visible Light-Driven Water Oxidation by a Molecular Ruthenium Catalyst in Homogeneous System2010In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 49, no 1, p. 209-215Article in journal (Refereed)
    Abstract [en]

    Discovery of an efficient catalyst bearing low overpotential toward water oxidation is a key step for light-driven water splitting into dioxygen and dihydrogen. A mononuclear ruthenium complex, Ru(II)L(pic)(2) (1) (H2L = 2,2'-bipyridine-6,6'-dicarboxylic acids pic = 4-picoline), was found capable of oxidizing water eletrochemically at a relatively low potential and promoting light-driven water oxidation using a three-component system composed of a photosensitizer, sacrificial electron acceptor, and complex 1. The detailed electrochemical properties of 1 were studied, and the onset potentials of the electrochemically catalytic curves in pH 7.0 and pH 1.0 solutions are 1.0 and 1.5 V, respectively. The low catalytic potential of 1 under neutral conditions allows the use of [Ru(bpy)(3)](2+) and even [Ru(dmbpy)(3)](2+) as a photosensitizer for photochemical water oxidation. Two different sacrificial electron acceptors, [Co(NH3)(5)Cl]Cl-2 and Na2S2O8, were used to generate the oxidized state of ruthenium tris(2,2'-bipyridyl) photosensitizers. In addition, a two-hour photolysis of I in a pH TO phosphate buffer did not lead to obvious degradation, indicating the good photostability of our catalyst. However, under conditions of light-driven water oxidation, the catalyst deactivates quickly. In both solution and the solid state under aerobic conditions, complex 1 gradually decomposed via oxidative degradation of its ligands, and two of the decomposed products, sp(3) C-H bond oxidized Ru complexes, were identified. The capability of oxidizing the sp(3) C-H bond implies the presence of a highly oxidizing Ru species, which might also cause the final degradation of the catalyst.

  • 26. Edvinsson, Tomas
    et al.
    Pschirer, Neil
    Schoneboom, Jan
    Eickemeyer, Felix
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Photoinduced electron transfer from a terrylene dye to TiO2: Quantification of band edge shift effects2009In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 357, no 1-3, p. 124-131Article in journal (Refereed)
    Abstract [en]

    A terrylene chromophore exhibiting a high extinction coefficient has been developed as a sensitizer for photovoltaic applications. The photophysical and photochemical properties of the dye were analyzed both experimentally and theoretically. Terrylene-sensitized nanocrystalline TiO2 solar cells yielded good photocurrents providing more than 60% in external quantum efficiency. The photoinduced electron transfer from the dye to TiO2 was found to be very sensitive to conduction band edge shifts in TiO2 induced, either by changes in the composition of the redox electrolyte or by UV-illumination. This sensitivity was observed in quantum efficiencies for photocurrent generation of terrylene-sensitized solar cells and in photoinduced absorption experiments. The conduction band shifts were quantified using charge extraction methods. The observed sensitivity of the injection efficiency suggests that photoinduced electron transfer occurs from the relaxed excited state, possibly due to poor electronic coupling between TMIMA excited states and TiO2 conduction band states.

  • 27. Ellis, Hanna
    et al.
    Eriksson, Susanna K.
    Feldt, Sandra M.
    Gabrielsson, Erik
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Lohse, Peter W.
    Lindblad, Rebecka
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Rensmo, Håkan
    Boschloo, Gerrit
    Hagfeldt, Anders
    Linker Unit Modification of Triphenylamine-Based Organic Dyes for Efficient Cobalt Mediated Dye-Sensitized Solar Cells2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 41, p. 21029-21036Article in journal (Refereed)
    Abstract [en]

    Linker unit modification of donor-linker-acceptor-based organic dyes was investigated with respect to the spectral and physicochemical properties of the dyes. The spectral response for a series of triphenylamine (TPA)-based organic dyes, called LEG1-4, was shifted into the red wavelength region, and the extinction coefficient of the dyes was increased by introducing different substituted dithiophene units on the pi-conjugated linker. The photovoltaic performance of dye-sensitized solar cells (DSCs) incorporating the different dyes in combination with cobalt-based electrolytes was found to be dependent on dye binding. The binding morphology of the dyes on the TiO2 was studied using photoelectron spectroscopy, which demonstrated that the introduction of alkyl chains and different substituents on the dithiophene linker unit resulted in a larger tilt angle of the dyes with respect to the normal of the TiO2-surface, and thereby a lower surface coverage. The good photovoltaic performance for cobalt electrolyte-based DSCs found here and by other groups using TPA-based organic dyes with a cyclopentadithiophene linker unit substituted with alkyl chains was mainly attributed to the extended spectral response of the dye, whereas the larger tilt angle of the dye with respect to the TiO2-surface resulted in less efficient packing of the dye molecules and enhanced recombination between electrons in TiO2 and Co(III) species in the electrolyte.

  • 28.
    Fredin, Kristofer
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Gorlov, M.
    IVF Industrial Research and Development Corporation, Mölndal.
    Pettersson, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    On the influence of anions in binary ionic liquid electrolytes for monolithic dye-sensitized solar cells2007In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 35, p. 13261-13266Article in journal (Refereed)
    Abstract [en]

    Five ion c liquids (ILs) of the general formula Im(+)A(-), where Im(+) = I -methyl-3-n-butyl-imidazolium, A(-) = I- (1), BF4- (2), SCN- (3), CF3CO2- (4), and CF(3)S0(3)(-) (5), were used in electrolytes for dye-sensitized monolithic solar cells. The properties of the electrolytes and various characteristics of the solar cell performance, such as electron transport and electron lifetime, were studied. The composition of the binary electrolytes, i.e., the different anions, have a significant effect on the viscosity, but only a modest effect of the measured diffusior. coefficient for triiodide. No significant effect of the electrolyte composition on the electron transport time in the mesoporous TiO2 film was found, while there was a pronounced effect on the electron lifetime. Monolithic solar cells with thiocyanate, IL 3, showed overall light-to-electricity conversion efficiency up to 5.6% in 250 W m(-2) simulated sunlight and have promising stability.

  • 29.
    Fredin, Kristofer
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Nissfolk, Jarl
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    The influence of cations on charge accumulation in dye-sensitized solar cell2007In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 609, no 2, p. 55-60Article in journal (Refereed)
    Abstract [en]

    The relation between open-circuit voltage, VOC, light intensity, , and accumulated charge, Q, has been studied for dye-sensitized solar cells (DSCs) containing different counterions to the iodide/triiodide redox couple. At higher light intensities, VOC scaled in the order Cs+ > K+ > Na+ > Li+, which was caused in part by shifts in the conduction band edge. The relation between VOC and Q was fitted to an exponential trap model. It was found that inclusion of a capacitive term improved the fit significantly. The determined values of C were found to be relatively large, up to 75 μF cm−2, and dependent of cation. Physically, the largest fraction of C could be ascribed to the TiO2 bulk or TiO2/dye/electrolyte interface. The interpretation of the trap distribution broadening parameter, β, was found to be dependent of fitting model. Using the model including the linear CVOC term, β was independent of cation and could be viewed as a TiO2 material parameter, while in the model excluding CVOC, β was dependent of cation. Voltage decay experiments were performed to study the cationic influence on recombination. Electron lifetimes were calculated from the voltage decay curves and it was found that the DSC containing Li+ yielded by far the shortest lifetime followed by the DSCs containing Na+, K+ and Cs+. Voltage decay curves include the effect of TiO2 conduction band shifts in the comparison of electron lifetimes with different cations. We therefore suggest that the electron lifetimes should be calculated from the corresponding charge decay curves. From such a comparison, it was found that the DSC containing Li+ yielded the shortest lifetime whereas the DSCs containing Na+, K+ or Cs+ showed approximately identical lifetimes.

  • 30.
    Gabrielsson, Erik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Ellis, Hanna
    Feldt, Sandra
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Hagfeldt, Anders
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Convergent/Divergent Synthesis of a Linker-Varied Series of Dyes for Dye-Sensitized Solar Cells Based on the D35 Donor2013In: Advanced Energy Materials, ISSN 1614-6832, Vol. 3, no 12, p. 1647-1656Article in journal (Refereed)
    Abstract [en]

    A series of four new dyes, based on the D35 type donor moiety with varied linker units, is synthesized using a facile convergent/divergent method, enabled by an improved synthesis of the D35 donor. The dyes are evaluated in dye sensitized solar cells with Co(II/III)(bpy)(3)-based electrolytes. By extending the linker fragment, higher photocurrents and solar energy conversion efficiencies are achieved. It is also found that the linker unit plays a crucial role in maintaining a high open-circuit photovoltage. Based on the photovoltaic performance it is concluded that the hexylthiophene unit is the most suitable for this purpose, as it allows further enhancement of the already high open-circuit voltage of D35 to 0.92 V. The best dye in this series reaches an efficiency of 6.8%.

  • 31.
    Gabrielsson, Erik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hao, Yan
    Lohse, Peter William
    Johansson, Erik Martin Jesper
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    Boschloo, Gerrit
    Control of Interfacial Charge Transfer in Organic Dye-SensitizedSolar Cells Based on Cobalt ElectrolytesManuscript (preprint) (Other academic)
  • 32.
    Gabrielsson, Erik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Eriksson, Susanna K.
    Gao, Jiajia
    Chen, Hong
    Li, Fusheng
    Oscarsson, Johan
    Sun, Juliang
    Resmo, Håkan
    Kloo, lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hagfeldt, Anders
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Dipicolinic Acid: A Strong Anchoring Group with Tunable Redoxand Spectral Behavior for Stable Dye-Sensitized Solar CellsManuscript (preprint) (Other academic)
  • 33.
    Gabrielsson, Erik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Uppsala University, Sweden.
    Eriksson, Susanna K.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Chen, Hong
    Li, Fusheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Oscarsson, Johan
    Sun, Junliang
    Rensmo, Håkan
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Dalian University of Technology (DUT), China.
    Dipicolinic acid: a strong anchoring group with tunable redox and spectral behavior for stable dye-sensitized solar cells2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 18, p. 3858-3861Article in journal (Refereed)
    Abstract [en]

    Dipicolinic acidwas investigated as a new anchoring group for DSSCs. A pilot dye (PD2) bearing this new anchoring group was found to adsorb significantly stronger to TiO2 than its cyanoacrylic acid analogue. The electrolyte composition was found to have a strong effect on the photoelectrochemical properties of the adsorbed dye in the device, allowing the dye LUMO energy to be tuned by 0.5 eV. Using a pyridine-free electrolyte, panchromatic absorption of the dye on TiO2 extending to 900 nm has been achieved. Solar cells using PD2 and a Co(bpy)(3) based electrolyte showed unique stability under simulated sunlight and elevated temperatures.

  • 34. Gibson, Elizabeth A.
    et al.
    Smeigh, Amanda L.
    Le Pleux, Loic
    Fortage, Jerome
    Boschloo, Gerrit
    Blart, Errol
    Pellegrin, Yann
    Odobel, Fabrice
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hammarstrom, Leif
    A p-Type NiO-Based Dye-Sensitized Solar Cell with an Open-Circuit Voltage of 0.35 V2009In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 48, no 24, p. 4402-4405Article in journal (Refereed)
  • 35.
    Hagberg, Daniel P.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Edvinsson, Tomas
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Marinado, Tannia
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    A novel organic chromophore for dye-sensitized nanostructured solar cells2006In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 21, p. 2245-2247Article in journal (Refereed)
    Abstract [en]

    A novel and efficient polyene-diphenylaniline dye for dye-sensitized solar cells has been synthesized. The dye has a short synthesis route and is readily adsorbed on TiO2 under a variety of dye-bath conditions. The overall solar-to-energy conversion efficiency is over 5% in the preliminary tests, in comparison with the conventional N719 dye which gives 6% under the same conditions. The dye is designed for future use also in solid state devices, with triarylamine based hole conductors.

  • 36.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Brief Overview of Dye-Sensitized Solar Cells2012In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, p. 151-155Article in journal (Refereed)
    Abstract [en]

    Dye-sensitized solar cells (DSC) are based on molecular and nanometer-scale components. Record cell efficiencies of 12%, promising stability data and means of energy-efficient production methods have been accomplished. As selling points for the DSC technology the prospect of low-cost investments and fabrication are key features. DSCs offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. The basic principles of the operation of DSC, the state-of-the-art as well as the potentials for future development are described.

  • 37.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Recent development of solar cells and solar fuels at the Center for Molecular Devices2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245Article in journal (Other academic)
  • 38. Hahlin, Maria
    et al.
    Johansson, Erik M. J.
    Plogmaker, Stefan
    Odelius, Michael
    Hagberg, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Siegbahn, Hans
    Rensmo, Hakan
    Electronic and molecular structures of organic dye/TiO2 interfaces for solar cell applications: a core level photoelectron spectroscopy study2010In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 12, no 7, p. 1507-1517Article in journal (Refereed)
    Abstract [en]

    The electronic and molecular properties of three organic dye molecules with the general structure donor-linker-anchor have been investigated using core level photoelectron spectroscopy (PES). The molecules contain a diphenylaniline donor unit, a thiophene linker unit, and cyanoacrylic acid or rhodanine-3-acetic acid anchor units. They have been investigated both in the form of a multilayer and adsorbed onto nanoporous TiO2 and the experimental results were also compared with DFT calculations. The changes at the dye-sensitized TiO2 surface due to the modification of either the donor unit or the anchor unit was investigated and the results showed important differences in coverage as well as in electronic and molecular surface properties. By measuring the core level binding energies, the sub-molecular properties were characterized and the result showed that the adsorption to the TiO2 influences the energy levels of the sub-molecular units differently.

  • 39. Hahlin, Maria
    et al.
    Odelius, Michael
    Magnuson, Martin
    Johansson, Erik M. J.
    Plogmaker, Stefan
    Hagberg, Daniel P.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Siegbahn, Hans
    Rensmo, Håkan
    Mapping the frontier electronic structures of triphenylamine based organic dyes at TiO2 interfaces2011In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 8, p. 3534-3546Article in journal (Refereed)
    Abstract [en]

    The frontier electronic structures of a series of organic dye molecules containing a triphenylamine moiety, a thiophene moiety and a cyanoacrylic acid moiety have been investigated by photoelectron spectroscopy (PES), X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and resonant photoelectron spectroscopy (RPES). The experimental results were compared to electronic structure calculations on the molecules, which are used to confirm and enrich the assignment of the spectra. The approach allows us to experimentally measure and interpret the basic valence energy level structure in the dye, including the highest occupied energy level and how it depends on the interaction between the different units. Based on N 1s X-ray absorption and emission spectra we also obtain insight into the structure of the excited states, the molecular orbital composition and dynamics. Together the results provide an experimentally determined energy level map useful in the design of these types of materials. Included are also results indicating femtosecond charge redistribution at the dye/TiO2 interface.

  • 40. Halme, Janne
    et al.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Lund, Peter
    Spectral characteristics of light harvesting, electron injection, and steady-state charge collection in pressed TiO2 dye solar cells2008In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 112, no 14, p. 5623-5637Article in journal (Refereed)
    Abstract [en]

    The factors that limit photocurrent in dye solar cells (DSC) were studied by incident-photon-to-collected-electron efficiency (eta(IPCE)), optical, and photovoltaic measurements. Nanostructured TiO2 photoelectrodes were prepared by compression technique on glass substrates, and half of them were given an additional heat treatment at 450 degrees C. The spectral absorbed-photon-to-collected-electron efficiency (eta(APCE)) of the cells was determined as a function of the photoelectrode film thickness (d) and direction of illumination and analyzed in terms of electron injection (eta(INJ)) and collection (eta(COL)) efficiency. The cells with pressed-only photoelectrodes gave significantly lower photocurrents yet their eta(APCE), and thus eta(COL), increased significantly with increasing d. To analyze this result quantitatively, methods were formulated based on the standard diffusion model of electron transport in nanostructured photoelectrodes for the factorization of experimental eta(APCF) data into eta(INJ) and eta(COL) parts and subsequent estimation of the effective steady-state electron diffusion length (L). Consistent decoupling of eta(INJ) and eta(COL) was reached in a spectral region where electron generation rate was independent of d. eta(INJ) was low and strongly wavelength-dependent, which was attributed to a poor energetic matching between dye excited states and TiO2 acceptor states due to unfavorable electrolyte composition. L increased systematically with d in both types of cells. Consistent with the increase of eta(IPCE) with light intensity, the result was attributed qualitatively to the electron concentration dependence of L and for a small part to decrease of film porosity with d. The diffusion model and its predictions were reviewed, and its validity in the present case was discussed critically.

  • 41. Han, Kai
    et al.
    Wang, Mei
    Zhang, Shuai
    Wu, Suli
    Yang, Yong
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Photochemical hydrogen production from water catalyzed by CdTe quantum dots/molecular cobalt catalyst hybrid systems2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 32, p. 7008-7011Article in journal (Refereed)
    Abstract [en]

    A hybrid system with a coordinative interaction between a cobalt complex of a N2S2-tetradentate ligand and CdTe quantum dots displayed a high activity (initial TOF 850 h(-1)) and improved stability (TON 1.44 x 10(4) based on catalyst over 30 h) for the photochemical H-2 generation from water, with a quantum efficiency of 5.32% at 400 nm.

  • 42. Hao, Yan
    et al.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Cong, Jiayan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Yang, Wenxing
    Bora, Ilkay
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. University of Stuttgart, Germany.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Hagfeldt, Anders
    Triphenylamine Groups Improve Blocking Behavior of Phenoxazine Dyes in Cobalt-Electrolyte-Based Dye-Sensitized Solar Cells2014In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 15, no 16, p. 3476-3483Article in journal (Refereed)
    Abstract [en]

    Novel phenoxazine dyes are successfully introduced as sensitizers into dye-sensitized solar cells (DSCs) with cobalt-based electrolyte. In sensitizers with triphenylamine (TPA) groups recombination from electrons in the TiO2 conduction band to the cobalt(III) species is suppressed. The effect of the steric properties of the phenoxazine sensitizers on the overall device performance and on recombination and regeneration processes is compared. Optimized DSCs sensitized with IB2 having two TPA groups in combination with tris(2,2'-bipyridyl) cobalt( II/III) yield efficiencies of 6.3 %, similar to that of IB3, which is equipped with mutiple alkoxy groups. TH310 with only one TPA group gives lower efficiency and open circuit voltage, while IB1 without TPA groups performs even worse. These results demonstrate that both TPA groups on the IB2 are needed for an efficient blocking effect. These results reveal a possible new role for TPA units in DSC sensitizer design.

  • 43. Hao, Yan
    et al.
    Yang, Xichuan
    Cong, Jiayan
    Hagfeldt, Anders
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. Dalian Univ Technol, China.
    Engineering of highly efficient tetrahydroquinoline sensitizers for dye-sensitized solar cells2012In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 68, no 2, p. 552-558Article in journal (Refereed)
    Abstract [en]

    Four novel tetrahydroquinoline dyes by inserting isophorone and/or thiophene moieties as pi bridge between the electron donating unit of substituted tetrahydroquinoline and the electron withdrawing unit of cyano carboxylic acid have been synthesized and successfully applied to dye-sensitized solar cells. Among them, DSCs sensitized by HYTIC, which shows the simplest molecular structure, exhibit improved efficiency of 7.0%. This by now is the highest efficiency for the reported tetrahydroquinoline sensitizers and comparable to the performance of N719-sensitized solar cells under the conditions employed here. (C) 2011 Elsevier Ltd. All rights reserved.

  • 44. Hao, Yan
    et al.
    Yang, Xichuan
    Cong, Jiayan
    Tian, Haining
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Efficient near infrared D-pi-A sensitizers with lateral anchoring group for dye-sensitized solar cells2009In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 27, p. 4031-4033Article in journal (Refereed)
    Abstract [en]

    A new strategy in which the anchoring group is separated from the acceptor groups of the dyes was developed; among these dyes, the HY103 dye gives a maximum IPCE value of 86% at 660 nm and an eta value of 3.7% in the NIR region reported in DSCs.

  • 45. Hao, Yan
    et al.
    Yang, Xichuan
    Zhou, Meizhen
    Cong, Jiayan
    Wang, Xiuna
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Sun, Licheng
    Molecular Design to Improve the Performance of Donor-p Acceptor Near-IR Organic Dye-Sensitized Solar Cells2011In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, no 11, p. 1601-1605Article in journal (Refereed)
    Abstract [en]

    Near-dye experience: Long, flexible carbon chains in the lateral anchoring groups of the donor part of a donor-π acceptor organic dye increase the power conversion efficiency dramatically. This performance enhancement can be ascribed to the prevention of the formation of molecular aggregates on the semiconductor nanoparticles, resulting in a lower recombination rate between transported electrons and I3- ions. A cell based on the new dye, HY113, gives a maximum IPCE value of 93% at 660nm.

  • 46. Hogberg, Daniel
    et al.
    Soberats, Bartolome
    Yoshio, Masafumi
    Mizumura, Yurika
    Uchida, Satoshi
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Segawa, Hiroshi
    Kato, Takashi
    Self-Assembled Liquid-Crystalline Ion Conductors in Dye-Sensitized Solar Cells: Effects of Molecular Sensitizers on Their Performance2017In: CHEMPLUSCHEM, ISSN 2192-6506, Vol. 82, no 6, p. 834-840Article in journal (Refereed)
    Abstract [en]

    Dye-sensitized solar cells employing nonvolatile liquid-crystalline (LC) electrolytes that form nanostructures capable of efficient ion transport are reported. The LC electrolyte consists of a cyclic carbonate-functionalized mesogen and an iodide-based ionic liquid that nanosegregates into lamellar structures exhibiting over four times higher ion conductivities parallel to the layers than perpendicular to the layers. The self-assembled ion pathways allow efficient ion transport in the semi-solid LC state. When used together with organic dyes, DSSCs employing these LC electrolytes show higher power conversion efficiency (PCE) than metal-organic dyes. This behavior is not observed for devices containing standard liquid electrolytes. The higher PCEs of the LC-based devices can be attributed to longer electron lifetimes (t) and higher electron densities in the photoelectrodes. The high concentration of iodide ions in the nanostructured pathways of the LC electrolyte is thought to induce reductive quenching of the ruthenium-based sensitizer, which competes with the electron injection process and lowers the t and electron densities of the TiO2.

  • 47. Hou, Jungang
    et al.
    Sun, Yiqing
    Cao, Shuyan
    Wu, Yunzhen
    Chen, Hong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Graphene Dots Embedded Phosphide Nanosheet-Assembled Tubular Arrays for Efficient and Stable Overall Water Splitting2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 29, p. 24600-24607Article in journal (Refereed)
    Abstract [en]

    Bifunctional electrocatalysts are highly desired for overall water splitting. Herein, the design and fabrication of three-dimensional (3D) hierarchical earth-abundant transition bimetallic phosphide arrays constructed by one-dimensional tubular array that was derived from assembling two-dimensional nanosheet framework has been reported by tailoring the Co/Ni ratio and tunable morphologies, and zero-dimensional (0D) graphene dots were embedded on Co-Ni phosphide matrix to construct 0D/2D tubular array as a highly efficient electrode in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). On the basis of advanced merits, such as the high surface-active sites, well-dispersed graphene dots, and enhanced electron transfer capacity as well as the confinement effect of the graphene dots on the nanosheets, the integrated GDs/Co0.8Ni0.2P tubular arrays as anode and cathode exhibit excellent OER and HER performance. By use of GDs/Co0.8Ni0.2 arrays in the two-electrode setup of the device, a remarkable electrocatalytic performance for full water splitting has been achieved with a high current density of 10 mA cm-2 at 1.54 V and outstanding long-term operation stability in an alkaline environment, indicating a promising system based on nonprecious-metal electrocatalysts toward potential practical devices of overall water splitting.

  • 48. Hou, Jungang
    et al.
    Sun, Yiqing
    Wu, Yunzhen
    Cao, Shuyan
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Promoting Active Sites in Core-Shell Nanowire Array as Mott-Schottky Electrocatalysts for Efficient and Stable Overall Water Splitting2018In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 4, article id 1704447Article in journal (Refereed)
    Abstract [en]

    Developing earth-abundant, active, and robust electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a vital challenge for efficient conversion of sustainable energy sources. Herein, metal-semiconductor hybrids are reported with metallic nanoalloys on various defective oxide nanowire arrays (Cu/CuOx, Co/CoOx, and CuCo/CuCoOx) as typical Mott-Schottky electrocatalysts. To build the highway of continuous electron transport between metals and semiconductors, nitrogen-doped carbon (NC) has been implanted on metal-semiconductor nanowire array as core-shell conductive architecture. As expected, NC/CuCo/CuCoOx nanowires arrays, as integrated Mott-Schottky electrocatalysts, present an overpotential of 112 mV at 10 mA cm(-2) and a low Tafel slope of 55 mV dec(-1) for HER, simultaneously delivering an overpotential of 190 mV at 10 mA cm(-2) for OER. Most importantly, NC/CuCo/CuCoOx architectures, as both the anode and the cathode for overall water splitting, exhibit a current density of 10 mA cm(-2) at a cell voltage of 1.53 V with excellent stability due to high conductivity, large active surface area, abundant active sites, and the continuous electron transport from prominent synergetic effect among metal, semiconductor, and nitrogen-doped carbon. This work represents an avenue to design and develop efficient and stable Mott-Schottky bifunctional electrocatalysts for promising energy conversion.

  • 49. Hu, M.
    et al.
    Yu, Z.
    Li, J.
    Jiang, X.
    Lai, J.
    Yang, X.
    Wang, M.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Low-cost solution-processed digenite Cu9S5 counter electrode for dye-sensitized solar cells2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 61, p. 38452-38457Article in journal (Refereed)
    Abstract [en]

    The development of low-cost alternatives to the commonly used but expensive platinum (Pt) catalyst in dye-sensitized solar cells (DSSCs) is important from a commercial point of view. In this work, Cu9S5 nanocrystalline film is fabricated directly onto a F-doped SnO2 (FTO) substrate by a solution-processed spin-coating method with low temperature post-treatment at 250 °C and it is further explored as a counter electrode (CE) material in DSSCs. The results from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) disclose that Cu9S5 film exhibits a higher catalytic ability for the state-of-the-art cobalt(ii/iii) tris(bipyridyl) ([Co(bpy)3]2+/3+) redox system as compared to the widely used iodine-based electrolyte. Consequently, the DSSC devices based on the cobalt complex redox shuttles show a power conversion efficiency (PCE) of 5.7% measured at 100 mW cm-2 illumination (AM 1.5G), which is substantially higher than that of the iodine-based counterpart (3.9%). This has been the first presentation for the application of digenite copper sulfides as an electrocatalyst for the [Co(bpy)3]2+/3+ redox system in DSSCs. The present finding represents a promising solution for the development of alternative cost-effective CE materials for DSSCs in the future.

  • 50.
    Hua, Yong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Xu, Bo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Chen, Hong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Cheng, Ming
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    High conductivity Ag-based metal organic complexes as dopant-free hole-transport materials for perovskite solar cells with high fill factors2016In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 7, no 4, p. 2633-2638Article in journal (Refereed)
    Abstract [en]

    Hole-transport materials (HTMs) play an important role as hole scavenger materials in the most efficient perovskite solar cells (PSCs). Here, for the first time, two Ag-based metal organic complexes (HA1 and HA2) are employed as a new class of dopant-free hole-transport material for application in PSCs. These HTMs show excellent conductivity and hole-transport mobility. Consequently, the devices based on these two HTMs exhibit unusually high fill factors of 0.76 for HA1 and 0.78 for HA2, which are significantly higher than that obtained using spiro-OMeTAD (0.69). The cell based on HA1-HTM in its pristine form achieved a high power conversion efficiency of 11.98% under air conditions, which is comparable to the PCE of the cell employing the well-known doped spiro-MeOTAD (12.27%) under the same conditions. More importantly, their facile synthesis and purification without using column chromatography makes these new silver-based HTMs highly promising for future commercial applications of PSCs. These results provide a new way to develop more low-cost and high conductivity metal-complex based HTMs for efficient PSCs.

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