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  • 251. Liao, Rong-Zhen
    et al.
    Wang, Mei
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Siegbahn, Per E. M.
    The mechanism of hydrogen evolution in Cu(bztpen)-catalysed water reduction: a DFT study2015In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 44, no 21, p. 9736-9739Article in journal (Refereed)
    Abstract [en]

    The mechanism of water reduction catalysed by a mononuclear copper complex Cu(bztpen) (bztpen = N-benzyl-N, N', N'-tris(pyridine-2-ylmethyl) ethylenediamine) has been elucidated by DFT calculations, revealing that hydrogen evolution proceeds via coupling of a Cu(II)-hydride and a pendant pyridinium, and providing important implications for the future design of new catalytic systems for water reduction.

  • 252.
    Lin, Li
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    LiCheng, Sun
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Electrochemical water oxidation by photo-deposited cobalt-based catalyst on a nano-structured TiO2 electrode2012In: Science China Chemistry, ISSN 1674-7291, Vol. 55, no 9, p. 1976-1981Article in journal (Refereed)
    Abstract [en]

    A cobalt-based catalyst was directly photo-deposited on the surface of a widely used n-type nano-structured semiconductor (TiO2). Different thicknesses of the TiO2 films as well as different time of photo-deposition of the Co-based catalyst on TiO2 films have been optimized. It was found that the electrode with 3 layers of TiO2 film (in 8 mu m thickness) and 1 hour photo-deposition of the cobalt-based catalyst by light irradiation from a 500 W Xenon lamp gave the highest current density (similar to 5 mA/cm(2)). Using this cobalt-modified TiO2 film as a working electrode in an electrochemical device, highly efficient water oxidation has been demonstrated in a pH 7.0 aqueous solution with low overpotential.

  • 253. Liu, Hai-Bin
    et al.
    Wang, Mei
    Wang, Ying
    Gu, Qiang
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Synthesis of 3-aryl-5-t-butylsalicylaldehydes and their chiral Schiff base compounds2007In: Synthetic Communications, ISSN 0039-7911, E-ISSN 1532-2432, Vol. 37, no 19-21, p. 3815-3826Article in journal (Refereed)
    Abstract [en]

    Six meta-substituted salicylaldehyde compounds have been prepared in 68-90% yields by the Suzuki-Miyaura coupling reaction using 3-bromo-5-t-butylsalicylaldehyde (la) and arylboronic acids (2a-f) as reactants. Among the obtained products, 3-(4-fluorophenyl)-5-t-butylsalicylaldehyde (3b), 3-(4-methylphenyl)-5-t-butylsalicylaldehyde (3d), 3-(1-naphthyl)-5-t-butylsalicylaldehyde (3e), and 3-(2-naphthyl)-5-t-butylsalicylaldehyde (3f) have not been reported so far. A series of new Schiff base ligands (L1-L10) were obtained in 51-89% yields from these salicylaldehyde derivatives.

  • 254. Liu, Hai-Bin
    et al.
    Wang, Mei
    Wang, Ying
    Wang, Lin
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis of Tri- and Disalicylaldehydes and Their Chiral Schiff Base Compounds2010In: Synthetic Communications, ISSN 0039-7911, E-ISSN 1532-2432, Vol. 40, no 7, p. 1074-1081Article in journal (Refereed)
    Abstract [en]

    A suitable procedure for convenient preparation of 1,3,5-tris(4-hydroxy-5-formylphenyl)benzene (6) was exploited via 5-bromosalicylaldehyde as starting reactant. Among the obtained products, compound 6, 4-methoxy-3-formylphenylboronic acid (9), 1,3,5-tris(4-methoxy-5-formylphenyl)benzene (10), and 4-methoxy-4'-hydroxyl-3,3'-diformyl-1,1'-diphenyl (11) had not been reported previously. Two new chiral Schiff base ligands, L1 and L2, were obtained from the tri- or disalicylaldehydes.

  • 255. Liu, Haibin
    et al.
    Wang, Mei
    Wang, Ying
    Yin, Ran
    Tian, Wei
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Influence of substituents in the salicylaldehyde-derived Schiff bases on vanadium-catalyzed asymmetric oxidation of sulfides2008In: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 22, no 5, p. 253-257Article in journal (Refereed)
    Abstract [en]

    A series of chiral Schiff bases (L-1-L-5) with different substituents in the salicylidenyl unit were prepared from condensation of 3-aryl-5-tert-butylsalicylaldehyde derivatives and optically active amino alcohols. Bromination of 3-phenyl-5-tert-butylsalicylaldehyde gave an unexpected product 3-(4-bromophenyl)-5-bromosalicylaldehyde, from which the corresponding Schiff base ligands L-6 and L-7, derived from (S)-valinol and (S)-tert-leucinol, respectively, were prepared. Ligands L-1-L-7 were applied to the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides. Under the optimal conditions, the oxidation of the thioanisole with H2O2 as oxidant in CH2Cl2 catalyzed by VO(acac)(2)-L-1-L-7 gives good yields (74-83%) with moderate enantioselectivity (58-77% ee). Ligand L-7, containing a 4-bromophenyl group on the 3-position and a Br atom on the 5-position of the salicylidenyl moiety, displays an 80-90% ee for vanadium-catalyzed oxidation of methyl 4-bromophenyl sulfide and methyl 2-naphthyl sulfide.

  • 256. Liu, Haibin
    et al.
    Wang, Mei
    Wang, Yu
    Wang, Ying
    Sun, Hui
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Asymmetric oxidation of sulfides with hydrogen peroxide catalyzed by a vanadium complex of a new chiral NOO-ligand2009In: Catalysis communications, ISSN 1566-7367, E-ISSN 1873-3905, Vol. 11, no 4, p. 294-297Article in journal (Refereed)
    Abstract [en]

    A new chiral NOO-tridentate ligand (8R)-2-(2-hydroxyphenyl)-4-methyl-5,6,7.8-tetrahydro-quinolin-8-ol (1) bearing a rigid tetrahydroquinoline framework was prepared and applied in the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides with H2O2 as oxidant. Less toxic acetone was found to be the proper solvent for the enantioselective oxidation of sulfides. Under the optimal condition, the asymmetric oxidation of aryl methyl sulfides in acetone catalyzed by VO(acac)(2)/1 at 0 degrees C gives good to high yields (80-95%) of sulfoxides with enantioselectivity up to 77% ee.

  • 257. Liu, J.
    et al.
    Yang, X.
    Cong, J.
    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. Dalian Univ Technol, China.
    Solvent-free ionic liquid electrolytes without elemental iodine for dye-sensitized solar cells2012In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 14, no 33, p. 11592-11595Article in journal (Refereed)
    Abstract [en]

    A new type of electrolyte with a sulfide/polysulfide redox couple and I - was prepared as a solvent-free ionic liquid for application in dye-sensitized solar cells, reaching efficiencies of 5.2-6.4% under AM 1.5G, 100 mW cm -2 light illumination, and 6.6% efficiency was obtained under 0.1 sun irradiation.

  • 258. Liu, Jing
    et al.
    Yang, Xichuan
    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.
    Axial anchoring designed silicon-porphyrin sensitizers for efficient dye-sensitized solar cells2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 100, p. 11785-11787Article in journal (Refereed)
    Abstract [en]

    Using silicon as a central atom of porphyrin allows the introduction of axial ligands, which are not only employed to prevent the aggregation of the macrocycles but also anchor the dyes onto the TiO2 surface. A dye-sensitized solar cell with this porphyrin sensitizer achieved a broad IPCE of around 40-60% between 380 and 670 nm.

  • 259. Liu, Jing
    et al.
    Yang, Xichuan
    Zhao, Jinxia
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tuning band structures of dyes for dye-sensitized solar cells: effect of different pi-bridges on the performance of cells2013In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, no 36, p. 15734-15743Article in journal (Refereed)
    Abstract [en]

    Three organic dyes (LJ101, LJ102, and LJ103) with different pi-bridges such as thiophene, 3-hexylthiophene and 3, 4-ethyldioxythiophene, were prepared and applied for the dye-sensitized solar cells (DSSCs). The effect of the different pi-bridges on the photovoltaic performance of DSSCs were studied with the aid of quantum chemical calculation and electrochemical-impedance spectroscopy (EIS). The introduction of pi-bridges to construct dyes makes the absorption spectra red shift and enhances the molar extinction coefficient compared to the parent structure of TH305 without pi-conjugated bridge. However, the increasing conjugation length of the molecules decreases the performance of DSSCs, due to the two reduced gaps: one is between the LUMO levels of dyes and the conduction band edge of TiO2, the other one is the energy gap between the HOMO levels of dyes and the redox potential of iodide/triiodide. The conversion efficiencies of DSSCs based on LJ series dyes ranged from 6.1 to 6.4%, which are lower than that of TH305 (7.5%).

  • 260. Liu, Jinxuan
    et al.
    Zhou, Wencai
    Liu, Jianxi
    Fujimori, Yamato
    Higashino, Tomohiro
    Imahori, Hiroshi
    Jiang, Xue
    Zhao, Jijun
    Sakurai, Tsuneaki
    Hattori, Yusuke
    Matsuda, Wakana
    Seki, Shu
    Garlapati, Suresh Kumar
    Dasgupta, Subho
    Redel, Engelbert
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Woll, Christof
    A new class of epitaxial porphyrin metal-organic framework thin films with extremely high photocarrier generation efficiency: promising materials for all-solid-state solar cells2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 33, p. 12739-12747Article in journal (Refereed)
    Abstract [en]

    We demonstrate the fabrication of a new class of epitaxial porphyrin metal-organic framework thin films whose photophysical properties can be tuned by the introduction of electron-donating diphenylamine (DPA) groups into the porphyrin skeleton. The attachment of DPA groups results in strongly improved absorption characteristics, yielding the highest photocarrier generation efficiency reported so far. DFT calculations identify a shift of the charge localization pattern in the VBM (lowest unoccupied molecular orbital), confirming that the introduction of the DPA groups is the main reason for the shift of the optical absorption spectrum and the improved photocurrent generation.

  • 261.
    Liu, Peng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. kTH.
    Sharmoukh, Walid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Xu, Bo
    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.
    Boschloo, Gerrit
    Uppsala University.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. Dalian University of Technology (DUT), Dalian, China.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Novel and Stable D-A-π-A Dyes for Efficient Solid-state Dye-sensitized Solar Cells2017In: ACS Omega, Vol. 2, no 5, p. 1812-1819Article in journal (Refereed)
    Abstract [en]

    Two novel organic donor–acceptor−π–acceptor sensitizers, W7 and W8, have been applied in efficient solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9′-spirobifluorene (Spiro-OMeTAD) as hole-transport material (HTM), an excellent power conversion efficiency of 6.9% was recorded for W7, together with an excellent photocurrent of 10.51 mA cm–2 and a high open-circuit voltage of 880 mV under standard AM 1.5 G illumination (100 mW cm–2). The solid-state solar cells based on W8 showed an efficiency of 5.2%, with a good photocurrent of 9.55 mA cm–2 and an open-circuit voltage of 870 mV. Compared to that of the well-known WS2 sensitizer, the results show that the performance of the ssDSSC devices can be significantly improved by introducing triphenylamine moiety into their structure. In addition, results of photoinduced absorption spectroscopy show efficient dye regeneration for W7- and W8-based devices. A higher hole conductivity of the W7/HTM and W8/HTM layers compared to that of the WS2/HTM layer was observed, indicating an efficient charge transfer at the interfaces. The results obtained offer insights into the design of reliable and highly efficient ssDSSCs for large-scale applications.

  • 262.
    Liu, Peng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wang, Linqin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Karlsson, Karl Martin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Hao, Yan
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 523, SE-75120 Uppsala, Sweden..
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Xu, Bo
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 523, SE-75120 Uppsala, Sweden..
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Molecular Engineering of D-pi-A Type of Blue-Colored Dyes for Highly Efficient Solid-State Dye-Sensitized Solar Cells through Co-Sensitization2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 42, p. 35946-35952Article in journal (Refereed)
    Abstract [en]

    A novel blue-colored organic donor-pi-acceptor sensitizer, the so-called MKA16 dye, has been employed to construct solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2',7-,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9'-spirobifuorene (Spiro-OMeTAD) as hole-transport material, a good conversion efficiency of 5.8% was recorded for cells based on the MKA16 dye and a high photovoltage of 840 mV in comparison with 5.6% efficiency using the known (Dyenamo Blue) dye. By co-sensitization using the orange-colored D35 dye and MKA16 together, the solid-state solar cells showed an excellent efficiency of 7.5%, with a high photocurrent of 12.41 mA cm(-2) and open-circuit voltage of 850 mV. The results show that the photocurrent of ssDSSCs can be significantly improved by co-sensitization mainly attributed to the wider light absorption range contributing to the photocurrent. In addition, results from photo-induced absorption spectroscopy show that the dye regeneration is efficient in co-sensitized solar cells. The current results possible routes of improving the design of aesthetic and highly efficient ssDSSCs.

  • 263.
    Liu, Peng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. kTH.
    Wang, Linqin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Karlsson, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hao, Yan
    Uppsala University.
    Gao, Jiajia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Xu, Bo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Boschloo, Gerrit
    Uppsala University.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. Dalian University of Technology (DUT), Dalian, China.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Molecular Engineering of D-π-A Type of Blue Dyes for Highly Efficient Solid State Dye Sensitized Solar Cells by Co-Sensitization2017In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501Article in journal (Refereed)
  • 264.
    Liu, Peng
    et al.
    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.
    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.
    Hua, Yong
    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.
    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.
    Aitola, K.
    Sveinbjörnsson, K.
    Zhang, J.
    Boschloo, G.
    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 A.
    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.
    Design, synthesis and application of a π-conjugated, non-spiro molecular alternative as hole-transport material for highly efficient dye-sensitized solar cells and perovskite solar cells2017In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 344, p. 11-14Article in journal (Refereed)
    Abstract [en]

    Two low-cost, easily synthesized π-conjugated molecules have been applied as hole-transport materials (HTMs) for solid state dye-sensitized solar cells (ssDSSCs) and perovskite solar cells (PSCs). For X1-based devices, high power conversion efficiencies (PCEs) of 5.8% and 14.4% in ssDSSCs and PSCs has been demonstrated. For X14-based devices, PCEs were improved to 6.1% and 16.4% in ssDSCs and PSCs, respectively.

  • 265.
    Liu, Peng
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    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.
    Karlsson, Karl Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Zhang, Jinbao
    Vlachopoulos, Nick
    Boschloo, Gerrit
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    The combination of a new organic D-pi-A dye with different organic hole-transport materials for efficient solid-state dye-sensitized solar cells2015In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 8, p. 4420-4427Article in journal (Refereed)
    Abstract [en]

    A new organic donor-pi-acceptor sensitizer MKA253 has been applied for highly efficient solid-state dye-sensitized solar cells (ssDSSCs). Using 2,2',7,7'-tetrakis(N,N-di-pi-methoxyphenyl-amine) 9,9'-spirobifluorene (Spiro-OMeTAD) as the hole transport material (HTM), an excellent power conversion efficiency of 6.1% was recorded together with a high short-circuit current of 12.4 mA cm(-2) under standard AM 1.5G illumination (100 mW cm(-2)). Different combinations of dyes and HTMs have also been investigated in the ssDSSC device. The results showed that small molecule HTM based devices suffer from comparably high electron recombination losses, thus causing low open-circuit voltage. In addition, photo-induced absorption (PIA) spectroscopy showed that the small-molecule HTMs lead to more efficient dye regeneration in comparison with Spiro-OMeTAD, despite a lower thermodynamic driving force. The results of this study also show that optimized energy levels for the dye-HTMs could be a vital factor for highly efficient ssDSSCs.

  • 266.
    Liu, Tianqi
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Zhang, Biaobiao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Iron-Based Molecular Water Oxidation Catalysts: Abundant, Cheap, and Promising2019In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 14, no 1, p. 31-43Article, review/survey (Refereed)
    Abstract [en]

    An efficient and robust water oxidation catalyst based on abundant and cheap materials is the key to converting solar energy into fuels through artificial photosynthesis for the future of humans. The development of molecular water oxidation catalysts (MWOCs) is a smart way to achieve promising catalytic activity, thanks to the clear structures and catalytic mechanisms of molecular catalysts. Efficient MWOCs based on noble-metal complexes, for example, ruthenium and iridium, have been well developed over the last 30 years; however, the development of earth-abundant metal-based MWOCs is very limited and still challenging. Herein, the promising prospect of iron-based MWOCs is highlighted, with a comprehensive summary of previously reported studies and future research focus in this area.

  • 267. Liu, Xien
    et al.
    Liu, Jianhui
    Pan, Jingxi
    Andersson, Samir
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis, electrochemical, and photophysical studies of multicomponent systems based on porphyrin and ruthenium(II) polypyridine complexes2007In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 63, no 37, p. 9195-9205Article in journal (Refereed)
    Abstract [en]

    Two ruthenium tris-bipyridine functionalized porphyrins 4, 8 and their Zn derivatives 4-Zn, 8-Zn were designed, synthesized, and characterized. The redox potentials of these complexes as well as their corresponding monomeric reference porphyrin and ruthenium bipyridine complexes were also measured for comparison. Primary dynamic studies on the electron injection and backing recombination between these complexes and TiO2 nanoparticles were carried out by means of transient absorption spectroscopy. The results indicate that a long-lived charge separation state was obtained in these assemblies.

  • 268. Lu, Z.
    et al.
    Gao, Y.
    Chen, H.
    Liu, Z.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry. Dalian University of Technology (DUT), Dalian, China.
    Water oxidation catalyzed by a charge-neutral mononuclear ruthenium(III) complex2017In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 4, p. 1304-1310Article in journal (Refereed)
    Abstract [en]

    A new charge-neutral Ru(iii) complex RuL(pic)3 (1) (H3L = 3,6-di-tert-butyl-9H-carbazole-1,8-dicarboxylic acid, pic = 4-picoline) was synthesized and fully characterized. This complex promoted chemical and photochemical water oxidation efficiently with turnover frequencies of 0.28 s-1 and 5 min-1, respectively. In particular, for photochemical water oxidation, complex 1 showed excellent stability and good activity. The X-ray crystal structure, electrochemical results, and the detection of the RuIV-OH intermediate by high-resolution mass spectrometry revealed that complex 1 exchanged its 4-picoline ligand with water at the RuIII state to form the authentic water oxidation catalyst. The kinetics studies suggested a reaction mechanism involving nucleophilic attack by a water molecule.

  • 269. Lu, Zhongkai
    et al.
    Gao, Yan
    Chen, Hong
    Liu, Zhao
    Chen, Lifang
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Efficient molecular ruthenium catalysts containing anionic ligands for water oxidation2016In: DALTON TRANSACTIONS, ISSN 1477-9226, Vol. 45, no 46, p. 18459-18464Article in journal (Refereed)
    Abstract [en]

    Two new mononuclear Ru complexes RuII(bipa)(pic) 3 (1; H(2)bipa = 6-(1H-benzo[d] imidazol-2-yl) picolinic acid, pic = 4-picoline) and RuII(pbic)(pic) 3 (2; H(2)pbic = 2-(pyridin-2-yl)-1H-benzo[d]imidazole-7-carboxylic acid, pic = 4-picoline) based on anionic ligands were successfully synthesized, and characterized using NMR spectroscopy, mass spectrometry, and X-ray crystallography. These catalysts showed high activities and stabilities in water oxidation in homogeneous systems with a high turnover number of 2100 and a turnover frequency of 0.21 s(-1) for complex 1. The O-O band formation mechanism involved water nucleophilic attack. An active catalytic intermediate, i.e., RuIV-OH, was detected using high-resolution mass spectrometry.

  • 270.
    Ma, Gui-Bin
    et al.
    KTH, Superseded Departments, Chemistry.
    Maliarik, Mikhail
    KTH, Superseded Departments, Chemistry.
    Sun, Licheng
    KTH, Superseded Departments, Chemistry.
    Glaser, Julius
    KTH, Superseded Departments, Chemistry.
    Novel porphyrin-thallium-platinum complex with naked metal-metal bond: multinuclear NMR characterization of (tpp)Tl-Pt(CN)(5) (2-) and (thpp)Tl-Pt(CN)(5) (2-) in solution2004In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 357, no 14, p. 4073-4077Article in journal (Refereed)
    Abstract [en]

    The novel porphyrin-thallium-platinum complexes with naked metal-metal bond, with the composition [(tpp)Tl-Pt(CN)(5)](2-) (1) and [(thpp)Tl-Pt(CN)(5)](2-) (2) (tpp = tetraphenylporphrin and thpp = tetrakis(4-hydroxyphenyl)-porphine), were synthesized and characterised by multinuclear NMR (Tl-205, Pt-195, C-13 and H-1) and Raman spectroscopies in solution. The presence of a direct Pt-Tl metal-metal bond in the complexes is convincingly confirmed by a very strong one-bond Pt-195-Tl-205 spin-spin coupling (47.8 and 48.3 kHz for 1 and 2, respectively) detected in both Pt and Tl NMR spectra. The corresponding force constant in molecule 1, 1.92 Ncm(-1), was calculated using Raman stretching frequency of the Pt-T1 vibration and is characteristic for a single metal-metal bond.

  • 271.
    Marinado, Tannia
    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.
    Boschloo, Gerrit
    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.
    Influence of π-Conjugation Units in Organic Dyes for Dye-Sensitized Solar Cells2007In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 4, p. 1853-1860Article in journal (Refereed)
    Abstract [en]

    Two organic dyes with the general structure donor-conjugated chain-acceptor (D-pi-A) have been investigated as sensitizers for nanocrystalline TiO2 solar cells. The electron donor and acceptor groups were pyrrolidine and cyano acrylic acid, respectively. The conjugated chain of 2-cyano-3-{5-[2-(4-pyrrolidin-1-ylphenyl)vinyl]thiophen-2-yl}acrylic acid contains one phenyl ring and a thiophene unit and is therefore denoted PT, while for 2-cyano-3-{5 -[2-(5-pyrrolidin-1-ylthiophen-2-yl)vinyl]thiophen-2-yl}acrylic acid the phenyl ring is replaced by a second thiophene unit (TT). Solar-to-electrical energy conversion efficiencies under simulated AM 1.5 irradiation (1000 W m(-2)) of 2.3% were obtained for solar cells based on PT but of less than 0.05% for those based on TT. The reasons for the dramatic difference of the efficiencies were analyzed. Photoinduced absorption measurements revealed that the TT dye was not properly regenerated by redox electrolyte after electron injection. This sluggish regeneration is probably due to the 0.3 V less positive HOMO level for TT dye compared to the PT dye, resulting in a lower driving force for regeneration of the oxidized dye by iodide in the electrolyte. In addition, regeneration of the oxidized TT dye and electron injection from the excited TT dye may be poor due to formation of dye aggregates/complexes, as FT-IR measurements show an excess of not properly and/or unidentate bound TT dye molecules instead of bidentate bound PT dye molecules. The results highlight that small structural change of dyes results in significant changes in redox energies and binding features, affecting dramatically the performance of these dyes in dye-sensitized solar cells.

  • 272.
    Marinado, Tannia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hagberg, Daniel P.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Edvinsson, Tomas
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Tian, Haining
    Yang, Xixhuan
    Sun, Licheng
    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.
    Energy level tuning of organic dyes for fundamental studies of the oxide/dye/electrolyte interface in solar cellsManuscript (Other academic)
  • 273.
    Marinado, Tannia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Hahlin, Maria
    Jiang, Xiao
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Quintana, Maria
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Johansson, Erik M J
    Gabrielsson, Erik
    Plogmaker, Stefan
    Hagberg, Daniel P
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Zakeeruddin, M
    Gratzel, Michael
    Siegbahn, Hans
    Sun, Licheng
    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.
    Rensmo, Håkan
    Surface Molecular Quantification and Photoelectrochemical Characterization of Mixed Organic Dye and Coadsorbent Layers on TiO2 for Dye-Sensitized Solar Cells2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 27, p. 11903-11910Article in journal (Refereed)
    Abstract [en]

    Different molecular layers on TiO2 were prepared by using the p-dimethylaniline triphenylamine based organic dye, D29, together with the coadsorbents decylphosphonic acid (DPA), dineohexyl bis(3,3-dimethylbutyl)phosphinic acid (DINHOP), and chenodeoxycholic acid (CDCA). The surface molecular structure of dye and coadsorbent layers on TiO2 was investigated by photoelectron spectroscopy (PES). A focus was to determine the surface molecular concentrations using characteristic photoelectron core levels. Dye-sensitized solar cells (DSCs) were prepared from the same substrate and were further characterized by photoelectrochemical methods. Together the investigation gives information on the arrangement of the mixed molecular layer and a first insight to the extent to which the coadsorbents exchange with dye molecules on the TiO2 surface for the examined conditions.

  • 274.
    Marinado, Tannia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Nonomura, Kazuteru
    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.
    Karlsson, Martin K
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    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), Chemistry, Organic Chemistry.
    Mori, Shogo
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    How the Nature of Triphenylamine-Polyene Dyes in Dye-Sensitized Solar Cells Affects the Open-Circuit Voltage and Electron Lifetimes2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 4, p. 2592-2598Article in journal (Refereed)
    Abstract [en]

    Three donor-linker-acceptor triphenylamine-based cyanoacrylic acid organic dyes used For dye-sensitized solar cells (DSCs) have been examined with respect to their effect on the open-circuit voltage (V-oc). Our previous study showed a decrease in V-oc for DSCs based oil dyes with increased molecular size (increased linker conjugation). In the present study, we investigate the origin of V-oc with respect to (i) conduction band (E-CB) positions of TiO2 and (ii) degree of recombination between electrons in TiO2 and electrolyte acceptor species at the interface. These parameters were Studied its it function of dye structure, dye load, and I-2 concentration. Two types of behavior were identified: the smaller polyene dyes show a surface-protecting effect preventing recombination upon increased dye loading, whereas the larger dyes enhance the recombination. How the different dye structures affect the recombination is discussed in terms of dye surface blocking and intermolecular interactions between dyes and electrolyte acceptor species.

  • 275. Meng, Peng
    et al.
    Wang, Mei
    Yang, Yong
    Zhang, Shuai
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, China.
    CdSe quantum dots/molecular cobalt catalyst co-grafted open porous NiO film as a photocathode for visible light driven H-2 evolution from neutral water2015In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 37, p. 18852-18859Article in journal (Refereed)
    Abstract [en]

    An active noble-metal-free photocathode was fabricated by co-grafting water-soluble thioglycolic acid-stabilized CdSe quantum dots and a molecular cobaloxime catalyst (CoP) through chemical linkage on a p-type open porous NiO film. This photocathode was used as a working electrode in a three-electrode cell, which displayed a photocurrent density up to 110 mu A cm(-2) at an applied potential of 0 V vs. NHE in 0.1 M Na2SO4 solution at pH 6.8 upon visible light illumination. The comparative studies showed that the open porous NiO/CdSe electrode did display a higher photocurrent density than that exhibited by an analogous planar NiO/CdSe electrode made by doctor-blading a NiO paste. Long-time photoelectrolysis experiments revealed that about 83% of the photocurrent density remained after 3.5 h illumination at 0.2 V vs. NHE. The open porous NiO/CdSe/CoP photocathode showed a considerably better current density and photocatalytic stability compared to the so-far reported dye-or QD-sensitized NiO cathodes with a cobaloxime catalyst chemically attached or physically adsorbed on the electrode surface under similar conditions.

  • 276.
    Monhaphol, Thitinun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Andersson, Samir
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Isolated Supramolecular [Ru(bpy)(3)]-Viologen-[Ru(bpy)(3)] Complexes with Trapped CB[7,8] and Photoinduced Electron-Transfer Study in Nonaqueous Solution2011In: Chemistry - A European Journal, ISSN 0947-6539, Vol. 17, no 41, p. 11604-11612Article in journal (Refereed)
    Abstract [en]

    The synthesis of two supramolecular diruthenium complexes, 1 subset of CB[7] and 1 subset of CB[8] (CB[n]=cucurbit[n]uril), which contain the respective host CB[7] and CB[8], were synthesized and isolated. In the case of host CB[8], the desired supramolecular complex was obtained by utilizing dihydroxynapthalene as a template during the synthesis. The (1)H NMR spectra, electrochemistry, and photochemistry of these supramolecular complexes were performed in nonaqueous solution. The results show that both CB[7,8] hosts mainly bind to the linker part in solution in acetonitrile. This binding also lowers the oxidation potential of the ruthenium metal center and hinders the quenching effect by the viologen moiety. It has also been shown that external methylviologen can be included into 1 subset of CB[8]. Analysis with NMR spectroscopy, electrochemistry, and photochemistry clearly shows a viologen radical dimer formation between the bound viologen and free methylviologen, thereby showing that the unique abilities of the CB[8] host can be utilized even in nonaqueous solution.

  • 277. Na, Yong
    et al.
    Pan, Jingxi
    Wang, Mei
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Intermolecular electron transfer from photogenerated Ru(bpy)(3)(+) to 2Fe2S model complexes of the iron-only hydrogenase active site2007In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 46, no 10, p. 3813-3815Article in journal (Refereed)
    Abstract [en]

    Visible light-driven intermolecular electron transfer was observed from a reduced species Ru(bpy)(3)(+), photogenerated via a reductive quenching of the ruthenium photosensitizer by a diethyldithiocarbamate anion, to bioinspired [2Fe2S] model complexes of the iron-only hydrogenase active site. The results indicate that Ru(bpy)(3)(2+) can act as a photoactive functional model of the [4Fe4S] cluster, playing the role of an electron-transfer relay. The photogenerated (FeFe0)-Fe-I species, which is proposed to be a crucial intermediate for proton reduction catalyzed electrochemically by the [2Fe2S] complexes, gives promise in the light-driven dihydrogen evolution using diiron complexes as surrogates of noble platinum catalysts.

  • 278. Na, Yong
    et al.
    Wang, Mei
    Jin, Kun
    Zhang, Rong
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    An approach to water-soluble hydrogenase active site models: Synthesis and electrochemistry of diiron dithiolate complexes with 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo 3.3.1 nonane ligand(s)2006In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 691, no 23, p. 5045-5051Article in journal (Refereed)
    Abstract [en]

    In order to improve the hydro- and protophilicity of the active site models of the Fe-only hydrogenases, three diiron dithiolate complexes with DAPTA ligand(s) (DAPTA=3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonanc), (mu-pdt)[Fe(CO)(2)][Fe(CO)(2)(DAPTA)] (1, pdt = 1,3-propanedithiolato), (mu-pdt)[Fe(CO)(2)(DAPTA)](2) (2) and (mu-pdt)[Fe(CO)(2)(PTA)][Fe(CO)(2)(DAPTA)] (3), were prepared and spectroscopically characterized. The water solubility of DAPTA-coordinate complexes 1-3 is better than that of the PTA-coordinate analogues. With complexes 1-3 as electrocatalysts, the overvoltage is reduced by 460-770 mV for proton reduction from acetic acid at low concentration in CH3CN. Significant decrease, up to 420 mV, in reduction potential for the Fe(I)Fe(I) to Fe(I)Fe(0) process and the curve-crossing phenomenon are observed in cyclic voltammograms of 2 and 3 in CH3CN/H2O mixtures. The introduction of the DAPTA ligand to the diiron dithiolate model complexes indeed makes the water solubility of 2 and 3 sufficient for electrochemical studies in pure water, which show that the proton reduction from acetic acid in pure water is electrochemically catalyzed by 2 and 3 at ca. -1.3 V vs. NHE.

  • 279. Na, Yong
    et al.
    Wang, Mei
    Pan, Jingxi
    Zhang, Pan
    Akermark, Bjoern
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Visible light-driven electron transfer and hydrogen generation catalyzed by bioinspired 2Fe2S complexes2008In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 47, no 7, p. 2805-2810Article in journal (Refereed)
    Abstract [en]

    Complexes [{(mu-SCH2)(2)NCH2C6H5){Fe(CO)(2)L-1){Fe(CO)(2)L-2}] (L-1 = CO, L-2 = P(Pyr)(3), 2; L-1 = L-2 = P(Pyr)(3), 3) were prepared, which have the lowest reduction potentials for the mono- and double-CO-displaced diiron complexes reported so far. Hydrogen evolution, driven by visible light, was successfully observed for a three-component system, consisting of a ruthenium polypyridine complex, the biomimetic model complex 2 or 3, and ascorbic acid as both electron and proton donor in CH3CN/H2O. The electron transfer from photogenerated Ru(bPY)(3)(+) to 2 or 3 was detected by laser flash photolysis. Under optimal conditions, the total turnover number for hydrogen evolution was 4.3 based on 2 and 86 based on Ru(bPY)(3)(2+) in a three-hour photolysis.

  • 280. Ni, Wenjun
    et al.
    Gurzadyan, Gagik G.
    Zhao, Jianzhang
    Che, Yuanyuan
    Li, Xiaoxin
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Singlet Fission from Upper Excited Electronic States of Cofacial Perylene Dimer2019In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, no 10, p. 2428-2433Article in journal (Refereed)
    Abstract [en]

    Singlet fission directly from the upper excited vibrational and electronic states of cofacial perylene dimers, bypassing the relaxed state S-1, was detected within 50 fs. This process competes well with vibrational cooling in S-1 (4.7-7.0 ps) and S-2 -> S-1 internal conversion (380 fs). The singlet fission has the energy threshold E = 3.06 eV. Other competitive relaxation processes are excimer and dimer cation formation on an ultrafast time scale. Excitation to higher energy levels (4.96 eV) leads to a higher efficiency of singlet fission.

  • 281.
    Ning, Zhijun
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Qin, Haiyan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Zhang, Qiong
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Wave-Function Engineering of CdSe/CdS Core/Shell Quantum Dots for Enhanced Electron Transfer to a TiO2 Substrate2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 35, p. 15184-15189Article in journal (Refereed)
    Abstract [en]

    In this paper, we have synthesized a series of core/shell quantum dots (QDs) for the purpose of enhancing the electron transfer from the dots to a TiO2 substrate. We make use of the fact that CdSe is a small-bandgap material compared with CdS; therefore, in a common CdSe/CdS core/shell QD, the photo-excited electron is confined deeply in the CdSe core. By special construction of the CdS/CdSe core/shell QDs, referred as reversed type-I, the electron wave function will distribute largely in the shell region. This facilitates the transfer of the electron from the QD to the TiO2 substrate, resulting in significantly improved electron-injection efficiency. Such an enhanced electron-injection efficiency was confirmed by fluorescence lifetime decay measurements, showing the largest lifetime reduction after that the QDs were adsorbed on the TiO2 surface. The reversed type-I CdS/CdSe QDs show a much higher photon-to-current conversion efficiency than type-I CdSe/CdS and CdSe QDs without shell. Furthermore, by chemical-bath depositing of CdS on the QD-sensitized electrode to form a quantum-well structure, the electron recombination between the QDs and the redox couple was reduced, hence further enhancing the electron-injection efficiency. The absorbed-photon-to-current efficiency of the quantum well CdS/CdSe/CdS sensitized solar cells reaches a value as high as 60%.

  • 282.
    Ning, Zhijun
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yuan, Chunze
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Fu, Ying
    KTH, School of Biotechnology (BIO).
    Qin, Haiyan
    KTH, School of Biotechnology (BIO).
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Solar cells sensitized with type-II ZnSe-CdS core/shell colloidal quantum dots2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 5, p. 1536-1538Article in journal (Refereed)
    Abstract [en]

    Type-II quantum dots (QDs) were applied for QDs-sensitized solar cells for the first time and showed prominent absorbed photon to current conversion efficiency.

  • 283.
    Ning, Zhijun
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yuan, Chunze
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Pure Organic Redox Couple for Quantum-Dot-Sensitized Solar Cells2011In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 23, p. 6330-6333Article in journal (Refereed)
  • 284.
    Ning, Zhijun
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Yuan, Chunze
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Lin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Type-II colloidal quantum dot sensitized solar cells with a thiourea based organic redox couple2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 13, p. 6032-6037Article in journal (Refereed)
    Abstract [en]

    In this paper, one kind of organic electrolyte based on tetramethylthiourea is employed for quantum dot sensitized solar cells (QDSCs). By reducing the impedance between the electrolyte and the counter electrode, the fill factor of such organic electrolyte based QDSCs is significantly improved. It is possible to substantially increase the photovoltage and to reach an efficiency three times higher than that of a commonly used inorganic electrolyte. The light harvesting ability of the organic electrolyte based QDSCs is successfully extended by using type-II QDs, where the adsorption of ZnS gives an additional advantage in further enhancing the stability of the cells. It is observed that core/shell ZnSe/CdS type-II QDs give higher electron injection than CdS/ZnSe QDs, proving that the electron distribution in the QDs is important for the electron extraction. A full working mechanism of the organic redox couple for the QDSCs is proposed.

  • 285.
    Ning, Zhijun
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Yuan, Chunze
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Quantum rod-sensitized solar cells2011In: ChemSusChem, ISSN 1864-5631, Vol. 4, no 12, p. 1741-1744Article in journal (Refereed)
    Abstract [en]

    An electron injection highway: CdSe nanorods with CdS seed material were applied to a quantum rod-sensitized TiO 2 solar cell that showed a higher electron injection efficiency than analogous quantum dot-sensitized solar cells: reducing the nanocrystals carrier confinement dimensions can improve electron injection efficiency of nanocrystal-sensitized solar cells.

  • 286.
    Nonomura, Kazuteru
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Xu, Yunhua
    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.
    Hagberg, Daniel P.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Zhang, Rong
    Boschloo, Gerrit
    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.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    The Effect of UV-Irradiation (under Short-Circuit Condition) on Dye-Sensitized Solar Cells Sensitized with a Ru-Complex Dye Functionalized with a (diphenylamino)Styryl-Thiophen Group2009In: International Journal of Photoenergy (Online), ISSN 1110-662X, E-ISSN 1687-529XArticle in journal (Refereed)
    Abstract [en]

    A new ruthenium complex, cis-di(thiocyanato)(2,2'-bipyridine-4,4'-dicarboxylic acid)(4,4'-bis(2-(5-(2-(4-diphenylaminophenyl)ethenyl)-thiophen-2-yl)eth enyl)-2,2'-bipyridine)ruthenium(II) (named E322) has been synthesized for use in dyesensitized solar cells (DSCs). Higher extinction coefficient and a broader absorption compared to the standard Ru-dye, N719, were aimed. DSCs were fabricated with E322, and the efficiency was 0.12% initially. (4.06% for N719, as reference). The efficiency was enhanced to 1.83% by exposing the cell under simulated sunlight containing UV-irradiation at short-circuit condition. The reasons of this enhancement are (1) enhanceing electron injection from sensitizer to TiO2 following a shift toward positive potentials of the conduction band of TiO2 by the adsorption of protons or cations from the sensitizer, or from the redox electrolyte and (2) improving the regeneration reaction of the oxidized dye by the redox electrolyte by the dissolution of aggregated dye from the surface of TiO2 following the treatment.

  • 287. Nyhlén, Jonas
    et al.
    Duan, Lele
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Åkermark, Björn
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Privalov, Timofei
    Evolution of O-2 in a Seven-Coordinate Ru-IV Dimer Complex with a [HOHOH] (-) Bridge: A Computational Study2010In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 49, no 10, p. 1773-1777Article in journal (Refereed)
  • 288. Ou, J.
    et al.
    Xiang, J.
    Liu, J.
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, Dalian University of Technology, Dalian, 116024, China.
    Surface-Supported Metal-Organic Framework Thin-Film-Derived Transparent CoS 1.097 @N-Doped Carbon Film as an Efficient Counter Electrode for Bifacial Dye-Sensitized Solar Cells2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 16, p. 14862-14870Article in journal (Refereed)
    Abstract [en]

    An effective design for counter electrode (CE) catalytic materials with superior catalytic activity, excellent stability, low cost, and a facile fabrication process is urgently needed for industrialization of dye-sensitized solar cells (DSSCs). Herein, we report a facile in situ method to fabricate transparent CoS 1.097 anchored on an N-doped carbon film electrode through sulfurization of a cobalt-metalloporphyrin metal-organic framework thin film on fluorine-doped tin oxide glass. The transparent film as counter electrode in bifacial DSSCs exhibited higher power conversion efficiency (9.11% and 6.64%), respectively, from front and rear irradiation than that of Pt (8.04% and 5.87%). The uniformly dispersed CoS 1.097 nanoparticles on an N-doped carbon film provide a large catalytic active area and facilitate the electron transfer, which leads to the excellent catalytic ability of the CoS 1.097 @N-doped carbon film. In addition, the in situ preparation of the uniform film with a nanosheet structure offers high electrical conductivity and unobstructed access for the diffusion of triiodide to available electroactive sites, resulting in excellent device performance with superior long-term stability over 1000 h under natural conditions.

  • 289.
    Ou, Jinhua
    et al.
    Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China.;Hunan Inst Technol, Dept Mat & Chem Engn, Hengyang 421002, Peoples R China..
    Liang, Jing
    Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Xiang, Juan
    Cent S Univ, Dept Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China..
    Sun, Licheng
    Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China.
    Liu, Jinxuan
    Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Highly transparent nickel and iron sulfide on nitrogen-doped carbon films as counter electrodes for bifacial quantum dot sensitized solar cells2019In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 193, p. 766-773Article in journal (Refereed)
    Abstract [en]

    Semiconductors are widely used as counter electrodes in quantum dot-sensitized solar cells. However, many counter electrode materials have poor conductivity and require tedious post-treatment procedures. Here, our groups develop a highly transparent MS2@N-doped C film materials (M = Ni, Fe) derived from layer-by-layer self-assembly of a M-TCPP film as a counter electrode in bifacial CdS/CdSe quantum dot-sensitized solar cells. Devices based on the MS2@N-doped C films exhibited higher respective front- and reverse-side power conversion efficiencies (i.e., 4.57% and 3.98% for the NiS2@N-doped C film and 3.18% and 2.63% for the FeS2@N-doped C film) than those of Pt-based devices (2.39% and 1.74%). We attribute the outstanding catalytic activity and excellent stability of the MS2@N-doped C film materials to the homogeneous sulfides within the transparent nitrogen-doped C film, as confirmed by electrochemical analyses, including cycle voltammetry, impedance spectroscopy and Tafel-polarization measurements.

  • 290. Pan, Y. -Z
    et al.
    Wang, Y. -G
    Liu, J. -H
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    10-Ethyl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-10H-phenothiazine2012In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 68, no 3, p. o649-Article in journal (Refereed)
    Abstract [en]

    In the title compound, C 17H 15N 3OS, the phenothia-zine ring system is slightly bent, with a dihedral angle of 13.68 (7)° between the benzene rings. The dihedral angle between the oxadiazole ring and the adjacent benzene ring is 7.72 (7)°. In the crystal, a π-π interaction with a centroid-centroid distance of 3.752 (2) Å is observed between the benzene rings of neighbouring molecules.

  • 291. Pan, Y. -Z
    et al.
    Wang, Y. -G
    Liu, Jianhui
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    2-(5-Bromothiophen-2-yl)-5-[5-(10-ethyl-phenothia-zin-3-yl)thiophen-2-yl] -1,3,4-oxadiazole2012In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 68, no 5, p. o1383-o1384Article in journal (Refereed)
    Abstract [en]

    The molecule of the title compound, C 24H 16BrN 3OS 3, contains three approximately planar fragments, viz. an oxadiazole ring plus two adjacent thiophene groups, and two phenothia-zine benzene rings, with largest deviations from the least-squares planes of 0.051 (3), 0.019 (4) and 0.014 (3) Å, respectively. The phenothia-zine unit adopts a butterfly conformation, with a dihedral angle of 38.06 (15)°between the terminal benzene rings. The dihedral angle between the 2,5-bis-(thiophen-2- yl)oxadiazole unit and the attached benzene ring is 15.35 (11)°. In the crystal, molecules form stacks along the b-axis direction; neighboring molecules within the stack are related by inversion centers, with shortest inter-centroid separations of 3.741 (2) and 3.767 (2) Å.

  • 292. Pettersson, Henrik
    et al.
    Gruszecki, Tadeusz
    Schnetz, Christine
    Streit, Micha
    Xu, Yunhua
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Gorlov, Mikhail
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry (closed 20110630).
    Boschloo, Gerrit
    Häggman, Leif
    Hagfeldt, Anders
    Parallel-connected monolithic dye-sensitised solar modules2010In: Progress in Photovoltaics, ISSN 1062-7995, E-ISSN 1099-159X, Vol. 18, no 5, p. 340-345Article in journal (Refereed)
    Abstract [en]

    Light-soaking and high-temperature storage testing of monolithic dye-sensitised solar modules with total area module efficiencies above 5% have been performed. Our experiences from the development of a four-layer monolithic dye-sensitised solar test cell for comparative testing of material components for dye-sensitised solar cells have directed our module development to a novel device design consisting of parallel-connection of individual monolithic cells. The results from the accelerated testing of the modules (total area of 17.0 cm(2)) with four parallel-connected cells (active area of 3.38 cm(2)/cell) are equivalent to those obtained for the monolithic single test cells when using identical device components. The successful transfer from cell to module stability is an important milestone in our ambition to develop a low-cost Photovoltaic (PV) technology. Moreover, our results indicate that intensified research and development to define the procedures for relevant accelerated testing of dye-sensitised solar modules is urgently required.

  • 293. Privalov, Timofei
    et al.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Akermark, Bjorn
    Catalytic water oxidation: DFT study of a competitive involvement of Lewis acid-Lewis base cooperation and radical coupling2011In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 242, p. 490-INOR-Article in journal (Refereed)
  • 294.
    Privalov, Timofei
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Akermark, Bjorn
    Liu, Jianhui
    Gao, Yan
    Wang, Mei
    A computational study of O-O bond formation catalyzed by monoand Bis-Mn-IV-Corrole complexes2007In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 46, no 17, p. 7075-7086Article in journal (Refereed)
    Abstract [en]

    A detailed computational study of O-O bond formation, catalyzed by monomeric and dimeric Mn-corrole complexes, is reported. The model explicitly takes into account the solvent, with respect to the first and second coordination spheres, while the bulk solvent is described by the polarizable continuum model. Two reaction mechanisms are proposed and computationally characterized: the concerted and the two-step mechanisms. The concerted mechanism is based on a OH--(MnO)-O-IV interaction via the outer-sphere pathway involving the bridging solvent molecules in the first coordinating sphere. The two-step mechanism is proposed to operate via the coordination of a hydroxide to the Mn-Iv ion, forming a MnO(OH)(-)-corrole complex with a strongly nonplanar corrole ligand. Comparison of the proposed mechanisms with available experimental data. is performed.

  • 295. Privalov, Timofei
    et al.
    Åkermark, Björn
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    The O-O Bonding in Water Oxidation: the Electronic Structure Portrayal of a Concerted Oxygen Atom-Proton Transfer Pathway2011In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 30, p. 8313-8317Article in journal (Refereed)
    Abstract [en]

    The two-phased reaction: Calculations on the monomeric ruthenium catalyst with 1,10-phenanthroline-2,9-dicarboxylic acid reveals an interaction of the RuV=O complex with water that proceeds through two main phases and involves partial charge separation in an early encounter complex. Further along the reaction path, that effect leads to an electronic reorganization in the Ru complex; this directs the donor-acceptor interaction between the attacking water and the COO-group in concert with the O-atom transfer to form an O-O bond via a relatively low-energy barrier (see graphic).

  • 296.
    Qin, Peng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Linder, Mats
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    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.
    High Incident Photon-to-Current Conversion Efficiency of p-Type Dye-Sensitized Solar Cells Based on NiO and Organic Chromophores2009In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 21, no 29, p. 2993-2996Article in journal (Refereed)
    Abstract [en]

    The synthesis and characterization of an organic dye, P4, together with its performance in p-type dye-sensitized solar cells (DSSCs) is presented. A solar-cell device based on P4 and an electrolyte that contains the I-/I-3(-) couple in acetonitrile yielded an IPCE value of 44% on a transparent NiO film only 1-1.4 mu m thick, the highest value obtained so far.

  • 297.
    Qin, Peng
    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.
    Wiberg, Joanna
    Gibson, Elizabeth A.
    Linder, Mats
    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.
    Li, Lin
    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.
    Brinck, Tore
    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.
    Albinsson, Bo
    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.
    Synthesis and Mechanistic Studies of Organic Chromophores with Different Energy Levels for p-Type Dye-Sensitized Solar Cells2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 10, p. 4738-4748Article in journal (Refereed)
    Abstract [en]

    A series of donor-pi-acceptor dyes with different electron-withdrawing groups were designed and synthesized for p-type dye-sensitized Solar cells. The modification of dye structures shows significant influence on the photophysical, electrochemical, and photovoltaic performance of the dyes. DSSCs based on these dyes show maximum 63% and minimum 6% of incident monochromatic photon-to-current conversion efficiencies. The two dyes with the highest (P1) and lowest (P3) efficiencies were Studied by femtosecond transient absorption spectroscopy, which shows a fast injection rate of more than (250 fs)(-1) for both dyes. Such fast injection corresponds to more than 90% injection efficiency. The photoinduced absorption Spectroscopy Study of sensitized NiO films in the presence of electrolyte showed poor regeneration of 113 due to all insufficient driving force. This, together with aggregation of the dye on the NiO film, explained the poor solar cell performance.

  • 298.
    Qin, Peng
    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.
    Zhu, Hongjun
    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
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry (closed 20110630).
    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
    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.
    Design of an organic chromophore for p-type dye-sensitized solar cells2008In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, no 27, p. 8570-8571Article in journal (Refereed)
    Abstract [en]

    A successful model for the design of efficient dyes for p-type dye-sensitized solar cells (DSSCs) is presented. As an example, a novel and efficient organic dye containing a triphenylamine chromophore has been synthesized and successfully applied in a p-type DSSC. The highest incident photon-to-current conversion efficiency (IPCE) of 18% in the visible region has been obtained, which is the highest value so far in p-type DSSCs. This is remarkably high, considering that only 600 nm thin NiO mesoporous films were used as p-type DSSC electrodes.

  • 299. Qu, Jishuang
    et al.
    Jiang, Xiaoqing
    Yu, Ze
    Lai, Jianbo
    Zhao, Yawei
    Hu, Maowei
    Yang, Xichuan
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Improved performance and air stability of perovskite solar cells based on low-cost organic hole-transporting material X60 by incorporating its dicationic salt2018In: Science in China Series B: Chemistry, ISSN 1674-7291, E-ISSN 1869-1870, Vol. 61, no 2, p. 172-179Article in journal (Refereed)
    Abstract [en]

    The development of an efficient, stable, and low-cost hole-transporting material (HTM) is of great significance for perovskite solar cells (PSCs) from future commercialization point of view. Herein, we specifically synthesize a dicationic salt of X60 termed X60(TFSI)(2), and adopt it as an effective and stable "doping" agent to replace the previously used lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) for the low-cost organic HTM X60 in PSCs. The incorporation of this dicationic salt significantly increases the hole conductivity of X60 by two orders of magnitude from 10(-6) to 10(-4) S cm(-1). The dramatic enhancement of the conductivity leads to an impressive power conversion efficiency (PCE) of 19.0% measured at 1 sun illumination (100 mW cm(-2), AM 1.5 G), which is comparable to that of the device doped with LiTFSI (19.3%) under an identical condition. More strikingly, by replacing LiTFSI, the PSC devices incorporating X60(TFSI)(2) also show an excellent long-term durability under ambient atmosphere for 30 days, mainly due to the hydrophobic nature of the X60(TFSI)(2) doped HTM layer, which can effectively prevent the moisture destroying the perovskite layer. The present work paves the way for the development of highly efficient, stable, and low-cost HTM for potential commercialization of PSCs.

  • 300. Shen, J.
    et al.
    Wang, M.
    Gao, J.
    Han, H.
    Liu, H.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Improvement of Electrochemical Water Oxidation by Fine-Tuning the Structure of Tetradentate N4 Ligands of Molecular Copper Catalysts2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4581-4588Article in journal (Refereed)
    Abstract [en]

    Two copper complexes, [(L1)Cu(OH2)](BF4)2 [1; L1=N,N′-dimethyl-N,N′-bis(pyridin-2-ylmethyl)-1,2-diaminoethane] and [(L2)Cu(OH2)](BF4)2 [2, L2=2,7-bis(2-pyridyl)-3,6-diaza-2,6-octadiene], were prepared as molecular water oxidation catalysts. Complex 1 displayed an overpotential (η) of 1.07 V at 1 mA cm−2 and an observed rate constant (kobs) of 13.5 s−1 at η 1.0 V in pH 9.0 phosphate buffer solution, whereas 2 exhibited a significantly smaller η (0.70 V) to reach 1 mA cm−2 and a higher kobs (50.4 s−1) than 1 under identical test conditions. Additionally, 2 displayed better stability than 1 in controlled potential electrolysis experiments with a faradaic efficiency of 94 % for O2 evolution at 1.58 V, when a casing tube was used for the Pt cathode. A possible mechanism for 1- and 2-catalyzed O2 evolution reactions is discussed based on the experimental evidence. These comparative results indicate that fine-tuning the structures of tetradentate N4 ligands can bring about significant change in the performance of copper complexes for electrochemical water oxidation.

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