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  • 101. Chen, Lin
    et al.
    Wang, Mei
    Gloaguen, Frederic
    Zheng, Dehua
    Zhang, Peili
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tetranuclear Iron Complexes Bearing Benzenetetrathiolate Bridges as Four-Electron Transformation Templates and Their Electrocatalytic Properties for Proton Reduction2013In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 52, no 4, p. 1798-1806Article in journal (Refereed)
    Abstract [en]

    Two tetranuclear iron-sulfur complexes, (mu,mu-pbtt)[Fe-2(CO)(6)](2) (pbtt = benzene-1,2,4,5-tetrathiolato, 3) and (mu,mu-obtt)[Fe-2(CO)(6)](2) (obtt = benzene-1,2,3,4-tetrathiolato, 4), were prepared from reaction of Fe-3(CO)(12) and the corresponding tetramercaptobenzene in THF, respectively. Complexes 5 and 6, (mu,mu-pbtt)[Fe-2(CO)(5)L-1][Fe-2(CO)(5)L-2] (L-1 = CO, L-2 = PPyr(3) (Pyr = N-pyrrolyl), 5; L-1 = L-2 = PPyr(3), 6) were obtained by controlling CO displacement of 3 with PPyr(3). Molecular structures of 3-6 were determined by spectroscopic and single-crystal X-ray analyses. All-CO Fe4S4 complexes 3 and 4 each display four-electron reduction processes in consecutive chemically reversible two-electron reduction events with relatively narrow potential spans in the cyclic voltammograms. Phosphine-substituted Fe4S4 complexes 5 and 6 exhibit two consecutive two-electron reduction events, which are not fully reversible. The electrocatalytic properties of 3 and 4 for proton reduction were studied using a series of carboxylic acids of increasing strength (CH3COOH, CH2ClCOOH, CHCl2COOH, CCl3COOH, and CF3COOH). The mechanisms for electrochemical proton reduction to hydrogen catalyzed by complex 3 as a function of acid strength are discussed.

  • 102. 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.

  • 103. Chen, Ruikui
    et al.
    Yang, Xichuan
    Tian, Haining
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tetrahydroquinoline dyes with different spacers for organic dye-sensitized solar cells2007In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 189, no 03-feb, p. 295-300Article in journal (Refereed)
    Abstract [en]

    Novel organic dyes (C1-1, C1-5 and C2-1) with a tetrahydroquinoline moiety as the electron donor, different thiophene-containing electron spacers and a cyanoacrylic acid moiety as the electron acceptor have been designed and synthesized for the application in dye-sensitized solar cells (DSSCs). An interesting relationship between the dye structures, properties, and the performance of DSSCs based on these tetrahydroquinoline dyes is obtained. Although C2-1 dye, which has a rigid electron spacer, has the narrowest action spectrum among these dyes, it gives the highest solar-to-electricity conversion efficiency (eta) of 4.49% (V-oc = 600 mV, J(sc) = 11.20 mA/cm(2), ff = 0.67) of a DSSC under simulated AM 1.5 irradiation (100 mW/cm(2)). Under the same conditions, the eta value of a DSSC based on N3 dye is 6.16%.

  • 104. Chen, Ruikui
    et al.
    Yang, Xichuan
    Tian, Haining
    Wang, Xiuna
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Effect of tetrahydroquinoline dyes structure on the performance of organic dye-sensitized solar cells2007In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 16, p. 4007-4015Article in journal (Refereed)
    Abstract [en]

    Eleven novel donor acceptor pi-conjugated (D-pi-A) organic dyes have been engineered and synthesized as sensitizers for the application in dye-sensitized solar cells (DSSCs). The electron-donating moieties are substituted tetrahydroquinoline, and the electron-withdrawing parts are cyanoacrylic acid group or cyanovinylphosphonic acid group. Different lengths of thiophene-containing conjugation moieties (thienyl, thienylvinyl, and dithieno[3,2-b;2',3'-d]thienyl) are introduced to the molecules and serve as electron spacers. Detailed investigation on the relationship between the dye structure, photophysical and photoelectrochemical properties, and performance of DSSCs is described here. The bathochromic shift and increase of the molar extinction coefficient of the absorption spectrum are achieved by introduction of larger conjugation moiety. Even small structural changes of dyes result in significant changes in redox energies and adsorption manner of the dyes on TiO2 surface, affecting dramatically the performance of DSSCs based on these dyes. The higher performances are obtained by DSSCs based on the rigid dye molecules, C2 series dyes (Figure 1), although these dyes have lower light absorption abilities relative to other dyes. A maximum solar-to-electrical energy conversion efficiency (eta) of 4.53% is achieved under simulated AM 1.5 irradiation (100 mW/cm(2)) with a DSSC based on C2-2 dye (V-oc = 597 mV, J(sc) = 12.00 mA/cm(2), ff = 0.63). Density functional theory (DFT) calculations have been performed on the dyes, and the results show that electron distribution from the whole molecules to the anchoring moieties occurred during the HOMO-LUMO excitation. The cyanoacrylic acid groups or cyanovinylphosphonic acid group are essentially coplanar with respect to the thiophene units, reflecting the strong conjugation across the thiophene-anchoring groups.

  • 105. Chen, Ruikui
    et al.
    Zhao, Guangjiu
    Yang, Xichuan
    Jiang, Xiao
    Liu, Jifeng
    Tian, Haining
    Gao, Yan
    Liu, Xien
    Han, Keli
    Sun, Mengtao
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Photoinduced intramolecular charge-transfer state in thiophene-pi-conjugated donor-acceptor molecules2008In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 876, no 1-3, p. 102-109Article in journal (Refereed)
    Abstract [en]

    Novel thiophene-pi-conjugated donor-acceptor molecules, 5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thioph ene2-carbaldehyde (QTC) and (1-cyano-2-{5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-v inyl]-thiophen-2-yl}-vinyl)-phosphonic acid diethyl ester (QTCP), were designed and synthesized. Combined experimental and theoretical methods were performed to investigate the photoinduced intramolecular charge-transfer (ICT) processes of these compounds. Steady-state absorption and fluorescence measurements in different solvents indicate the photoinduced ICT characters of QTC and QTCP. Solvent dependency of the large Stokes shifts and high dipole moment of the excited state also support the charge-transfer character of the excited state. Theoretical calculations based on time-dependent density functional theory (TDDFT) method were performed to investigate ICT states of these compounds. The results reveal that the excited states have adopted a distortion of the C=C double bond between the donor moiety and the thiophene-pi-bridge.

  • 106. Chen, Shao
    et al.
    Yuxin, Pei
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhichao, Pei
    Regioselective Acylation of 2 '- or 3 '-Hydroxyl Group in Salicin: Hemisynthesis of Acylated Salicins2014In: Chemical Research in Chinese Universities, ISSN 1005-9040, E-ISSN 2210-3171, Vol. 30, no 5, p. 774-777Article in journal (Refereed)
    Abstract [en]

    Salicin-based phenolic glycosides(PGs) are important defensive substances against herbivore feeding and have good bioactivities. In this work, a novel approach for the synthesis of salicin-based PGs has been developed, by which PGs of 2'-O-acetylsalicin(5a), 3'-O-acetylsalicin(5b) and 3'-O-benzoylsalicin(5d) were hemisynthesized. The effects of acylation reagent, solvent and temperature on the regioselective acylation of 2'- or 3'-hydroxyl groups of salicin mediated by dibutyltin oxide were investigated. The optimal conditions under which the best regioselectivity reached for 5a-5d were discovered, respectively. Moreover, a tentative tin-oxygen coordination mechanism was put forward to explain the different regioselectivities shown under different conditions.

  • 107. Chen, Song
    et al.
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hua, Yong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Li, Yuanyuan
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Wang, Xingzhu
    Ong, Beng
    Wong, Wai-Kwok
    Zhu, Xunjin
    Study of Arylamine-Substituted Porphyrins as Hole-Transporting Materials in High-Performance Perovskite Solar Cells2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 15, p. 13231-13239Article in journal (Refereed)
    Abstract [en]

    To develop new hole-transporting materials (HTMs) for efficient and stable perovskite solar. cells (PSCs), 5,10,15,20-tetrakis{4-[N,N-di(4-thethoxylphenyl)amino-phenyl]}-porphyrin was prepared in gram scale through the direct condensation of pyrrole and 4-[bis(4-methoxyphenyl)amino]-benzaldehyde. Its Zn(II) and Cu(II) complexes exhibit excellent thermal and electrochemical stability, specifically a high hole Mobility and very favorable energetics for hole extraction that render them a new class of HTMs in organometallic halide PSCs. As expected, ZnP as HTM in PSCs affords a competitive power conversion efficiency (PCE) of 17.78%,which is comparable to that of the most powerful HTM of Spiro-MeOTAD (18.59%) under the same working conditions. Mean-While, the metal centers affect somewhat the photovoltaic performances that CuP as HTM produces a lower PCE of 15.36%. Notably, the PSCs employing ZnP show a much,better stability than Spiro-OMeTAD. Moreover, the two-porphyrin-based HTMs can be prepared from relatively cheap raw materials with a facile synthetic route. The results demonstrate that ZnP and CuP can be a new class of HTMs for efficient and stable PSCs. To the best of our knowledge, this is the best performance that porphyrin-based solar cells could show with PCE > 17%.

  • 108. Chen, Xuan
    et al.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. University of Massachusetts Lowell, United States .
    Glyconanomaterials: Emerging applications in biomedical research2014In: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000, Vol. 7, no 10, p. 1381-1403Article, review/survey (Refereed)
    Abstract [en]

    Carbohydrates constitute the most abundant organic matter in nature, serving as structural components and energy sources, and mediating a wide range of cellular activities. The emergence of nanomaterials with distinct optical, magnetic, and electronic properties has witnessed a rapid adoption of these materials for biomedical research and applications. Nanomaterials of various shapes and sizes having large specific surface areas can be used as multivalent scaffolds to present carbohydrate ligands. The resulting glyconanomaterials effectively amplify the glycan-mediated interactions, making it possible to use these materials for sensing, imaging, diagnosis, and therapy. In this review, we summarize the synthetic strategies for the preparation of various glyconanomaterials. Examples are given where these glyconanomaterials have been used in sensing and differentiation of proteins and cells, as well as in imaging glycan-medicated cellular responses.

  • 109. 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.

  • 110.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Aitola, Kerttu
    Chen, Cheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Zhang, Fuguo
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sveinbjornsson, Kari
    Hua, Yong
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Boschloo, Gerrit
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian Univ Technol.
    Acceptor Donor Acceptor type ionic molecule materials for efficient perovskite solar cells and organic solar cells2016In: NANO ENERGY, ISSN 2211-2855, Vol. 30, p. 387-397Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells (PSCs) have attracted significant interest and hole transporting materials (HTMs) play important roles in achieving high efficiency. Here, we report additive free ionic type HTMs that are based on 2-ethylhexyloxy substituted benzodithiophene (BDT) core unit. With the ionization of end-capping pyridine units, the hole mobility and conductivity of molecular materials are greatly improved. Applied in PSCs, ionic molecular material M7-TFSI exhibits the highest efficiency of 17.4% in the absence of additives [lithium bis(trifluor-omethanesulfonyl)imide and 4-tert-butylpyridine]. The high efficiency is attributed to a deep highest occupied molecular orbital (HOMO) energy level, high hole mobility and high conductivity of M7-TFSI. Moreover, due to the higher hydrophobicity of M7-TFSI, the corresponding PSCs showed better stability than that of Spiro-OMeTAD based ones. In addition, the strong absorption and suitable energy levels of materials (M6, M7-13r and M7-TFSI) also qualify them as donor materials in organic solar cells (OSCs) and the devices containing M7-TFSI as donor material displayed an efficiency of 6.9%.

  • 111.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chen, Cheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Aitola, Kerttu
    Zhang, Fuguo
    Hua, Yong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Boschloo, Gerrit
    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. Dalian University of Technology (DUT), China.
    Highly Efficient Integrated Perovskite Solar Cells Containing a Small Molecule-PC70BM Bulk Heterojunction Layer with an Extended Photovoltaic Response Up to 900 nm2016In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 28, no 23, p. 8631-8639Article in journal (Refereed)
    Abstract [en]

    We demonstrate a high efficiency perovskite solar cell (PSC) integrated with a bulk heterojunction layer, based on acceptor-donor-acceptor (A-D-A) type hole transport material (HTM) and PC70BM composite, yielding improved photoresponse. Two A-D-A-structured hole transporting materials termed M3 and M4 were designed and synthesized. Applied as HTMs in PSCs, power conversion efficiencies (PCEs) of 14.8% and 12.3% were obtained with M3 and M4, respectively. The HTMs M3 and M4 show competitive absorption, but do not contribute to photocurrent, resulting in low current density. This issue was solved by mixing the HTMs with PC70BM to form a bulk heterojunction (BHJ) layer and integrating this layer into the PSC as hole transport layer (HTL). Through careful interface optimization, the (FAPbI(3))(0.85)(MAPbBr(3))(0.15)/HTM:PC70BM integrated devices showed improved efficiencies of 16.2% and 15.0%, respectively. More importantly, the incident-photon-to-current conversion efficiency (IPCE) spectrum shows that the photoresponse is extended to 900 nm by integrating the M4:PC70BM based BHJ and (FAPbI(3))(0.85)(MAPbBr(3))(0.15) layers.

  • 112.
    Cheng, Ming
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chen, Cheng
    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.
    Hua, Yong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Zhang, Fuguo
    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. Dalian University of Technology (DUT), China.
    A novel phenoxazine-based hole transport material for efficient perovskite solar cell2015In: Journal of Energy Challenges and Mechanics, ISSN 2095-4956, E-ISSN 2056-9386, Vol. 24, no 6, p. 698-706Article in journal (Refereed)
    Abstract [en]

    Based on the previous research work in our laboratory, we have designed and synthesized a small-molecule, hole transport material (HTM) POZ6-2 using phenoxazine (POZ) as central unit and dicyanovinyl units as electron-withdrawing terminal groups. Through the introduction of a 2-ethyl-hexyl bulky chain into the POZ core unit, POZ6-2 exhibits good solubility in organic solvents. In addition, POZ6-2 possesses appropriate energy levels in combination with a high hole mobility and conductivity in its pristine form. Therefore, it can readily be used as a dopant-free HTM in perovskite solar cells (PSCs) and a conversion efficiency of 10.3% was obtained. The conductivity of the POZ6-2 layer can be markedly enhanced via doping in combination with typical additives, such as 4-tert-butylpyridine (TBP) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). Correspondingly, the efficiency of the PSCs was further improved to 12.3% using doping strategies. Under the same conditions, reference devices based on the well-known HTM Spiro-OMeTAD show an efficiency of 12.8%.

  • 113.
    Cheng, Ming
    et al.
    Dalian Univ Technol, Inst Artificial Photosynth, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, China.
    Chen, Cheng
    Yang, Xichuan
    Huang, Jing
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhang, Fuguo
    Xu, Bo
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Novel Small Molecular Materials Based on Phenoxazine Core Unit for Efficient Bulk Heterojunction Organic Solar Cells and Perovskite Solar Cells2015In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 5, p. 1808-1814Article in journal (Refereed)
    Abstract [en]

    Two novel Acceptor-Donor-Acceptor (A-D-A) structured small molecular (SM-) materials POZ2 and POZ3 using an electron-rich phenoxazine (POZ) unit as a core building block were designed and synthesized. Their unique characteristics, such as suitable energy levels, strong optical absorption in the visible region, high hole mobility, and high conductivity, prompted us to use them both as p-type donor materials (DMs) in SM-bulk heterojunction organic solar cells (BHJ OSCs) and as hole transport materials (HTMs) in CH3NH3PbI3-based perovskite solar cells (PSCs). The POZ(2)-based devices yielded promising power conversion efficiencies (PCEs) of 7.44% and 12.8% in BHJ OSCs and PSCs, respectively, which were higher than the PCEs of 6.73% (BHJ-OSCs) and 11.5% (PSCs) obtained with the POZ3-based devices. Moreover, our results demonstrated that the POZ2 employing the electron-deficient benzothiazole (BTZ) as linker exhibited higher hole mobility and conductivity than that of the POZ3 using thiophene as linker, leading to better device performance both in BHJ-OSCs and PSCs. These results also provide guidance for the molecular design of high charge carrier mobility SM-materials for highly efficient BHJ OSCs and PSCs in the future.

  • 114.
    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.
    Liu, Peng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Zhang, Fuguo
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hajian, Alireza
    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.
    Wang, Haoxin
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Li, Jiajia
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Wang, Linqin
    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.
    Yang, Xichuan
    State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT–KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    A Perylenediimide Tetramer-Based 3D Electron Transport Material for Efficient Planar Perovskite Solar Cell2017In: Solar RRL, ISSN 2367-198X, Vol. 1, no 5, article id 1700046Article in journal (Refereed)
    Abstract [en]

    A perylenediimide (PDI) tetramer-based three dimensional (3D) molecular material, termed SFX-PDI4, has been designed, synthesized, and characterized. The low-lying HOMO and LUMO energy levels, high electron mobility and good film-formation property make it a promising electron transport material (ETM) in inverted planar perovskite solar cells (PSCs). The device exhibits a high power conversion efficiency (PCE) of 15.3% with negligible hysteresis, which can rival that of device based on PC61BM. These results demonstrate that three dimensional PDI-based molecular materials could serve as high performance ETMs in PSCs.

  • 115.
    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.

  • 116.
    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.

  • 117. 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.

  • 118. 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).

  • 119. Cheng, Ming
    et al.
    Yang, Xichuan
    Chen, Cheng
    Zhao, Jianghua
    Zhang, Fuguo
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dye-sensitized solar cells based on hydroquinone/benzoquinone as bio-inspired redox couple with different counter electrodes2013In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 36, p. 15146-15152Article in journal (Refereed)
    Abstract [en]

    In the present study, tetramethylammonium hydroquinone (HQ)/benzoquinone (BQ) were developed for use as a redox couple, with poly(3,4-ethylenedioxythiophene) (PEDOT) and multiwalled carbon nanotubes (MWNT) being proposed for use as counter electrode (CE) catalysts in dye-sensitized solar cells (DSSCs). Both metal-complex N719 and metal-free organic dye CM309 were employed to fabricate devices. For the devices sensitized by N719, when using PEDOT and MWNT CEs, power conversion efficiencies (PCE) of 5.2 and 4.9% were obtained, respectively, which were much higher than that of the device using the traditional Pt CE (4.7%) when HQ/BQ electrolyte was employed. However, with the HQ/BQ redox shuttle, the efficiency of the devices sensitized by N719 is much lower than that of the devices when the traditional I-/I-3(-) based electrolyte and Pt CE were employed (7.9%). While for the CM309 sensitized solar cells, when the HQ/BQ redox shuttle was employed, PEDOT and MWNT performed much better than Pt, the DSSC using the PEDOT CE showed an efficiency of 6.2%, which was close to that of the DSSC using the traditional I-/I-3(-) electrolyte and Pt CE (6.3%).

  • 120. Cheng, Ming
    et al.
    Yang, Xichuan
    Li, Jiajia
    Chen, Cheng
    Zhao, Jianghua
    Wang, Yu
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dye-Sensitized Solar Cells Based on a Donor-Acceptor System with a Pyridine Cation as an Electron-Withdrawing Anchoring Group2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 50, p. 16196-16202Article in journal (Refereed)
    Abstract [en]

    New hemicyanine dyes (CM101, CM102, CM103, and CM104) in which tetrahydroquinoline derivatives are used as electron donors and N-(carboxymethyl)-pyridinium is used as an electron acceptor and anchoring group were designed and synthesized for dye-sensitized solar cells (DSSCs). Compared with corresponding dyes that have cyanoacetic acid as the acceptor, N-(carboxymethyl)-pyridinium has a stronger electron-withdrawing ability, which causes the absorption maximum of dyes to be redshifted. The photovoltaic performance of the DSSCs based on dyes CM101CM104 markedly depends on the molecular structures of the dyes in terms of the n-hexyl chains and methoxyl. The device sensitized by dye CM104 achieved the best conversion efficiency of 7.0?% (Jsc=13.4 mA?cm-2, Voc=704 mV, FF=74.8?%) under AM 1.5 irradiation (100 mW?cm-2). In contrast, the device sensitized by reference dye CMR104 with the same donor but the cyanoacetic acid as the acceptor gave an efficiency of 3.4?% (Jsc=6.2 mA?cm-2, Voc=730 mV, FF=74.8?%). Under the same conditions, the cell fabricated with N719 sensitized porous TiO2 exhibited an efficiency of 7.9?% (Jsc=15.4 mA?cm-2, Voc=723 mV, FF=72.3?%). The dyes CM101CM104 show a broader spectral response compared with the reference dyes CMR101CMR104 and have high IPCE exceeding 90?% from 450 to 580 nm. Considering the reflection of sunlight, the photoelectric conversion efficiency could be almost 100?% during this region.

  • 121. Cheng, Ming
    et al.
    Yang, Xichuan
    Li, Shifeng
    Wang, Xiuna
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Efficient dye-sensitized solar cells based on an iodine-free electrolyte using L-cysteine/L-cystine as a redox couple2012In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 5, no 4, p. 6290-6293Article in journal (Refereed)
    Abstract [en]

    A new iodine-free electrolyte based on amino acids L-cysteine/L-cystine as a redox couple has been designed and synthesized. DSSCs fabricated with the conventional I-/I-3(-) redox couple gave efficiencies of 8.1% and 6.3% under optimized experimental conditions based on ruthenium dye, N719, and metal-free organic dye, TH202, respectively. Based on the same dyes, the DSSCs employing the new L-cysteine/L-cystine redox couple showed comparable efficiencies of 7.7% and 5.6%, respectively. However, higher incident-photon-to-electron (IPCE) conversion efficiencies and larger J(sc) values were found for devices with the L-cysteine/L-cystine redox couple than with I-/I-3(-). From an electrochemical impedance spectroscopic study, we found that the charge recombination between the conduction band electrons in the TiO2 film and the electrolyte containing the L-cysteine/L-cystine redox couple is restrained.

  • 122. Cheng, Ming
    et al.
    Yang, Xichuan
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Efficient Dye-Sensitized Solar Cells Based on Hydroquinone/Benzoquinone as a Bioinspired Redox Couple2012In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, no 39, p. 9896-9899Article in journal (Refereed)
    Abstract [en]

    A hybrid electrolyte involving tetramethylammonium (TMA) hydroquinone/benzoquinone redox couple is formulated. This electrolyte is more transparent than the traditional I -/I 3 - electrolyte and has negligible absorption in the visible region. Dye-sensitized solar cells using the hybrid electrolyte show higher light-to-electricity conversion efficiency. FTO=fluorine-doped tin oxide.

  • 123. Cheng, Ming
    et al.
    Yang, Xichuan
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tuning the HOMO and LUMO Energy Levels of Organic Dyes with N-Carboxomethylpyridinium as Acceptor To Optimize the Efficiency of Dye-Sensitized Solar Cells2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 18, p. 9076-9083Article in journal (Refereed)
    Abstract [en]

    Different from traditional D-pi-A sensitizers (the traditional design concept of the organic dyes is the donor-pi-linker-acceptor structure), a series of organic dyes with pyridinium as acceptor have been synthesized in order to approach the optimal energy level composition in the TiO2-dye-iodide/triiodide system in the dye-sensitized solar cells. HOMO and LUMO energy level tuning is achieved by varying the conjugation units and the donating ability of the donor part. Detailed investigation on the relationship between the dye structure and photophysical, photoelectrochemical properties and performance of DSSCs is described. For TPA-based dyes, by substituting the 3-hexylthiophene group with a carbon-carbon double bond as pi-spacer, the bathochromic shift of absorption spectra and higher current density (J(sc)) are achieved. When the methoxyl and n-hexoxyl are introduced into CM301 to construct dyes CM302 and CM303, the absorption peak is red-shifted compared with that of CM301 due to the increase of the electron-donating ability. The devices fabricated with sensitizers CM302 and CM303 show higher J(sc) and open-circuit voltage (V-oc) than those of the device sensitized by CM301, which can be mainly attributed to the wider incident photon-to-current conversion efficiency (IPCE) response and the suppression of electron recombination between TiO2 film and electrolyte, respectively. The effects of different electron donors in DSSCs application are compared, and the results show that sensitizers with a phenothiazine (PTZ) electron-donating unit give a promising efficiency, which is even better than the TPA-based dyes. This is because the PTZ unit displayed a stronger electron-donating ability than the TPA unit (oxidation potential of 0.82 and 1.08 V vs the normal hydrogen electrode (NHE), respectively). For sensitizers CM306 and CM307, the introduction of 1,3- bis(hexyloxy)phenyl increases the donating ability of the donor part. Furthermore, the presence of long alkyl chains decreases the dye adsorption amount on the TiO2 surface, which diminishes dye aggregation and the electron recombination effectively, though, with less adsorption amount of dyes on TiO2, the device sensitized by dye CM307 obtained the best conversion efficiency of 7.1% (J(sc) = 13.6 mA.cm(-2), V-oc = 710 mV, FF = 73.6%) under AM 1.5G irradiation (100 mW.cm(-2)).

  • 124. 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%.

  • 125. Cheng, Minglun
    et al.
    Wang, Mei
    Zhang, Shuai
    Liu, Fengyuan
    Yang, Yong
    Wan, Boshun
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Photocatalytic H-2 production using a hybrid assembly of an [FeFe]-hydrogenase model and CdSe quantum dot linked through a thiolato-functionalized cyclodextrin2017In: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 198, p. 197-209Article in journal (Refereed)
    Abstract [en]

    It is a great challenge to develop iron-based highly-efficient and durable catalytic systems for the hydrogen evolution reaction (HER) by understanding and learning from [FeFe]-hydrogenases. Here we report photocatalytic H-2 production by a hybrid assembly of a sulfonate-functionalized [FeFe]-hydrogenase mimic (1) and CdSe quantum dot (QD), which is denoted as 1/beta-CD-6-S-CdSe (beta-CD-6-SH = 6-mercapto-beta-cyclodextrin). In this assembly, thiolato-functionalized beta-CD acts not only as a stabilizing reagent of CdSe QDs but also as a host compound for the diiron catalyst, so as to confine CdSe QDs to the space near the site of diiron catalyst. In addition, another two reference systems comprising MAA-CdSe QDs (HMAA = mercaptoacetic acid) and 1 in the presence and absence of beta-CD, denoted as 1/beta-CD/MAA-CdSe and 1/MAA-CdSe, were studied for photocatalytic H-2 evolution. The influences of beta-CD and the stabilizing reagent beta-CD-6-S- on the stability of diiron catalyst, the fluorescence lifetime of CdSe QDs, the apparent electron transfer rate, and the photocatalytic H-2-evolving efficiency were explored by comparative studies of the three hybrid systems. The 1/beta-CD-6-SCdSe system displayed a faster apparent rate for electron transfer from CdSe QDs to the diiron catalyst compared to that observed for MAA-CdSe-based systems. The total TON for visible-light driven H-2 evolution by the 1/beta-CD-6-S-CdSe QDs in water at pH 4.5 is about 2370, corresponding to a TOF of 150 h(-1) in the initial 10 h of illumination, which is 2.7- and 6.6-fold more than the amount of H-2 produced from the reference systems 1/beta-CD/MAA-CdSe and 1/MAA-CdSe. Additionally, 1/beta-CD-6-S-CdSe gave 2.4-5.1 fold enhancement in the apparent quantum yield and significantly improved the stability of the system for photocatalytic H-2 evolution.

  • 126. 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.

  • 127. Coldham, Iain
    et al.
    Meijer, Anthony J. H. M.
    Sadhukhan, Arghya
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Hobbs, Melanie
    Highly Enantioselective Metalation-Substitution alpha to a Chiral Nitrile2017In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 28, no 8, p. A80-A82Article in journal (Refereed)
  • 128.
    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%.

  • 129.
    Cong, Jiayan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Kinschel, Dominik
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Dyenamo AB, Sweden.
    Daniel, Quentin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Safdari, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Gabrielsson, E.
    Chen, Hong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Svensson, Per H.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. SP Process Development Forskargatan, Sweden.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Bis(1,1-bis(2-pyridyl)ethane)copper(i/II) as an efficient redox couple for liquid dye-sensitized solar cells2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 38, p. 14550-14554Article in journal (Refereed)
    Abstract [en]

    A new redox couple, [Cu(bpye)2]+/2+, has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy)3]2+/3+. These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs.

  • 130. Cong, Jiayan
    et al.
    Yang, Xichuan
    Hao, Yan
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry (closed 20110630).
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    A highly efficient colourless sulfur/iodide-based hybrid electrolyte for dye-sensitized solar cells2012In: RSC Advances, ISSN 2046-2069, Vol. 2, no 9, p. 3625-3629Article in journal (Refereed)
    Abstract [en]

    A new kind of hybrid electrolyte with S2-/S-x(2-) and I- was invented, and the new hybrid system was demonstrated to outperform the well-known I-/I-3(-) redox system in DSCs. An efficiency of 9.1% was achieved in our lab under AM 1.5 illumination using the dye N719, considerably higher than the efficiency of 8.0% of the I-/I-3(-)-based electrolyte.

  • 131. 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.

  • 132.
    Cong, Jiayan
    et al.
    Dalian Univ Technol, Dalian, Peoples R China.
    Yang, Xichuan
    Dalian Univ Technol, Dalian, Peoples R China.
    Liu, Jing
    Dalian Univ Technol, Dalian, Peoples R China.
    Zhao, Jinxia
    Dalian Univ Technol, Dalian, Peoples R China.
    Hao, Yan
    Dalian Univ Technol, Dalian, Peoples R China.
    Wang, Yu
    Dalian Univ Technol, Dalian, Peoples R China.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Nitro group as a new anchoring group for organic dyes in dye-sensitized solar cells2012In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 48, no 53, p. 6663-6665Article in journal (Refereed)
    Abstract [en]

    An organic dye JY1 bearing a nitro group was designed, synthesized and applied in DSCs. An unusual colour change was observed when the voltage applied to the device was reversed which was accompanied by a five-fold increase in the cell efficiency. We propose that applying a bias enabled the attachment of nitro groups to the TiO2 surface.

  • 133. Cui, Hong-Guang
    et al.
    Wang, Mei
    Dong, Wei-Bing
    Duan, Le-Le
    Li, Ping
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis, structures and electrochemical properties of hydroxyl- and pyridyl-functionalized diiron azadithiolate complexes2007In: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719, Vol. 26, no 4, p. 904-910Article in journal (Refereed)
    Abstract [en]

    The hydroxyl- and pyridyl-functionalized diiron azadithiolate complexes [[(mu-SCH2)(2)N(CH2CH2OH)}Fe-2(CO)(6)] (1) and [{(mu-SCH2)(2)N(CH2CH2OOCPy)} Fe-2(CO)(6)] (Py = pyridyl) (2) were prepared as biomimetic models of the active site of Fe-only hydrogenases. Both complexes were characterized by MS, IR, H-1 NMR spectra and elemental analysis. The molecular structures of 1 and 2 were determined by single crystal X-ray analysis. A network is constructed by intermolecular H-bonds in the crystals of 1. An S center dot center dot center dot O intermolecular contact was found in the crystals of 2, which is scarcely found for organometallic complexes. Cyclic voltammograms of 1 and 2 were studied to evaluate their redox properties.

  • 134. Cui, Hongguang
    et al.
    Wang, Mei
    Duan, Lele
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Preparation, characterization and electrochemistry of an iron-only hydrogenase active site model covalently linked to a ruthenium tris(bipyridine) photosensitizer2008In: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389, Vol. 61, no 12, p. 1856-1861Article in journal (Refereed)
    Abstract [en]

    An NH2-functionlized [Fe2S2] model complex of the iron-only hydrogenase active site was covalently linked to the tris( bipyridine) ruthenium photosensitizer. The [RuFeFe] trinuclear complex 1 was characterized by MS, IR, UV-vis, H-1 & C-13 NMR spectra. A quasi-reversible reduction peak at - 1.41V versus Ag/Ag+ for the (FeFeI)-Fe-I/(FeFe0)-Fe-I process is observed in the cyclic voltammogram of 1.

  • 135.
    Daniel, Quentin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Water oxidation: From Molecular Systems to Functional Devices2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The production of hydrogen gas, through the process of water splitting,is one of the most promising concepts for the production of clean andrenewable fuel.The introduction of this thesis provides a brief overview of fossil fuelsand the need for an energy transition towards clean and renewable energy.Hydrogen gas is presented as a possible candidate fuel with its productionthrough artificial photosynthesis, being described. However, the highlykinetically demanding key reaction of the process – the water oxidationreaction – requires the use of a catalyst. Hence, a short presentation of differentmolecular water oxidation catalysts previously synthesized is also provided.The second part of the thesis focuses on ruthenium-based molecularcatalysis for water oxidation. Firstly, the design and the catalytic performancefor a new series of catalysts are presented. Secondly, a further study onelectron paramagnetic resonance of a catalyst shows the coordination of awater molecule to a ruthenium centre to generate a 7-coordinated complex atRuIII state. Finally, in an electrochemical study, coupled with nuclear magneticresonance analysis, mass spectrometry and X-ray diffraction spectroscopy, wedemonstrate the ability of a complex to perform an in situ dimerization of twounits in order to generate an active catalyst.The final part of this thesis focuses on immobilisation of first rowtransition metal catalysts on the surface of electrodes for electrochemical wateroxidation. Initially, a copper complex was designed and anchored on a goldsurface electrode. Water oxidation performance was studied byelectrochemistry, while deactivation of the electrode was investigated throughX-ray photoelectron spectroscopy, revealing the loss of the copper complexfrom the electrode during the reaction. Finally, we re-investigated cobaltporphyrin complexes on the surface of the electrode. Against the backgroundof previous report, we show that the decomposition of cobalt porphyrin intocobalt oxide adsorbed on the surface is responsible for the catalytic activity.This result is discussed with regard to the detection limit of various spectroscopic methods.

  • 136.
    Daniel, Quentin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ambre, Ram
    Wang, Lei
    Zhang, Peili
    Chen, Hong
    Zhang, Biaobiao
    Li, Fusheng
    Fan, Ke
    Sun, Licheng
    Electrochemical water oxidation by Copper peptidecomplexes: molecular catalysts on gold electrode surfaceArticle in journal (Refereed)
  • 137.
    Daniel, Quentin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Anabre, Ram B.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Zhang, Biaobiao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Philippe, Bertrand
    Chen, Hong
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Li, Fusheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fan, Ke
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ahmadi, Sareh
    Rensmo, Hakan
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian University of Technology (DUT), China.
    Re-Investigation of Cobalt Porphyrin for Electrochemical Water Oxidation on FTO Surface: Formation of CoOx as Active Species2017In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, no 2, p. 1143-1149Article in journal (Refereed)
    Abstract [en]

    The use of cobalt porphyrin complexes as efficient and cost-effective molecular catalysts for water oxidation has been investigated previously. However, by combining a set of analytical techniques (electrochemistry, ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and synchrotron-based photoelectron spectroscopy (SOXPES and HAXPES)), we have demonstrated that three different cobalt porphyrins, deposited on FTO glasses, decompose promptly into a thin film of CoOx on the surface of the electrode during water oxidation under certain conditions (borate buffer pH 9.2). It is presumed that the film is composed of CoO, only detectable by SOXPES, as conventional techniques are ineffective. This newly formed film has a high turnover frequency (TOF), while the high transparency of the CoOx-based electrode is very promising for future application in photoelectrochemical cells.

  • 138.
    Daniel, Quentin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Duan, Lele
    Chen, Hong
    Ambre, Ram
    Zhang, Biaobiao
    Li, Fusheng
    Sun, Licheng
    Water oxidation initiated by in-situ dimerization of theRu(pdc) catalystArticle in journal (Refereed)
  • 139.
    Daniel, Quentin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Huang, Ping
    Fan, Ting
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Wang, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Duan, Lele
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Wang, Lei
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Li, Fusheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rinkevicius, Zilvinas
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ahlquist, Mårten S. G.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Mamedov, Fikret
    Styring, Stenbjörn
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rearranging from 6-to 7-coordination initiates the catalytic activity: An EPR study on a Ru-bda water oxidation catalyst2017In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 346, p. 206-215Article in journal (Refereed)
    Abstract [en]

    The coordination of a substrate water molecule on a metal centered catalyst for water oxidation is a crucial step involving the reorganization of the ligand sphere. This process can occur by substituting a coordinated ligand with a water molecule or via a direct coordination of water onto an open site. In 2009, we reported an efficient ruthenium-based molecular catalyst, Ru-bda, for water oxidation. Despite the impressive improvement in catalytic activity of this type of catalyst over the past years, a lack of understanding of the water coordination still remains. Herein, we report our EPR and DFT studies on Ru-bda (triethylammonium 3-pyridine sulfonate)(2) (1) at its Ru-III oxidation state, which is the initial state in the catalytic cycle for the O-O bond formation. Our investigation suggests that at this III-state, there is already a rearrangement in the ligand sphere where the coordination of a water molecule at the 7th position (open site) takes place under acidic conditions (pH = 1.0) to form a rare 7-coordinated Ru-III species.

  • 140.
    Daniel, Quentin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Wang, Lei
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Duan, Lele
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Li, Fusheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Dalian Univ Technol, Peoples R China.
    Tailored design of ruthenium molecular catalysts with 2,2 '-bypyridine-6,6 '-dicarboxylate and pyrazole based ligands for water oxidation2016In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, no 37, p. 14689-14696Article in journal (Refereed)
    Abstract [en]

    With the incorporation of pyrazole and DMSO as axial ligands, a series of tailor-designed Ru water oxidation catalysts [Ru(bda)(DMSO)(L)] (H(2)bda = 2,2'-bypyridine-6,6'-dicarboxylic acid; DMSO = dimethyl sulfoxide; L = pyrazole, A-1; 4-Br-3-methyl pyrazole, B-1) and [Ru(bda)(L)(2)] (L = pyrazole, A-2; 4-Br-3-methyl pyrazole, B-2) have been generated in situ from their corresponding precursors [Ru(kappa(O,N,N)(3)-bda) (DMSO)(x)(L)(3-x)] which are in a zwitterionic form with an extra pyrazole based ligand in the equatorial position. Formation of the active catalyst has been investigated under pH 1.0 conditions. Electrochemistry and water oxidation activity of these catalysts were investigated. By fine tuning of the catalyst structure, the turnover frequency was increased up to 500 s(-1) and the stability over 6000 turnovers.

  • 141.
    Danielsson, Jakob
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stereoselective Nucleophilic Additions to Aldehydes and Synthesis of α-Amino-β- Hydroxy-Esters2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the development of new reaction methodology as well as stereochemical investigations.

    The first part concerns the investigation of 1,2- and merged 1,2- and 1,3- asymmetric induction in Mukaiyama aldol additions to α-heteroatom and α,β- heteroatom substituted aldehydes respectively. In particular, the unexpected 1,2-syn selectivity obtained in the addition of sterically hindered nucleophiles to α-chloroaldehydes is examined, and an explanation for the observed stereochemical trends is proposed.

    The second part describes the development of a novel entry to α-amino-β- hydroxy esters by a 1,3-dipolar cycloaddition reaction of aldehydes and azomethine ylides, generated by thermolysis of aziridines.

    The third part deals with our efforts to develop a novel entry to vicinal all- carbon quaternary centers, based on an intramolecular domino Heck- carbonylation reaction using tetrasubstituted olefins.

  • 142.
    Danielsson, Jakob
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Toom, Lauri
    Institute of Technology, University of Tartu, Tartu, Estonia.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    1,3-Dipolar Cycloaddition of Azomethine Ylides to Aldehydes: Synthesis of anti alpha-Amino-beta-Hydroxy Esters2011In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 3, p. 607-613Article in journal (Refereed)
    Abstract [en]

    A 1,3-dipolar cycloaddition reaction of azomethine ylides to aldehydes is described. The azomethine ylides, generated by thermal electrocyclic ring opening of aziridines, adds to aldehydes in good yields with moderate to good selectivities to furnish oxazolidines. The oxazolidines were subsequently hydrolyzed to the corresponding amino alcohols, giving the anti diastereomer as the major product.

  • 143.
    Danielsson, Marie
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chemical defence in Norway spruce2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Norway spruce (Picea abies) responds to stress by biosynthesis of chemical substances, which can deter invading insects or pathogens. Some of these substances are volatile and can be emitted to the surroundings while others are accumulated within the tree. Information about the susceptibility of individual plants to infestation, their volatile emissions and chemical defence is of interest, for example, in selecting plants for tree breeding programs.

    The first part of this research focused on volatiles emitted by Norway spruce plants. Collection of headspace volatiles by SPME and subsequent separation and identification with GC-MS was used to investigate Norway spruce plants of different ages and stress conditions as well as trapping semiochemicals like nepetalactone emitted by the spruce shoot aphids. It was even possible to analyse the emission of single needles in vivo and obtain spatial localisation of the stress reaction to methyl jasmonate or spruce spinning mites. Seedlings of different ages showed differences in chemical composition of emitted volatiles, with the pine weevil repellent, (4S)-(-)-limonene, one of the main compounds. Wounded phloem of conventional plants emitted high amounts of monoterpenes while the phloem of mini plants emitted (3Z)-hexenal and (3Z)-hexen-1-ol. In addition, a method to separate and identify the four diastereomers of nepetalactone by GC-MS and characteristic m/z-fragments was accomplished.

    The second part of the research deals with the chemical response of Norway spruce roots to inoculation with Heterobasidion annosum. Terpene concentrations increased after inoculation or wounding but the composition was mainly associated with clone identity and not to susceptibility or treatment. In contrast, inoculation with H. annosum induced a treatment-specific alteration of phenol composition. The constitutive phenol composition differed between more and less susceptible clones. The phenols astringin and astringin dimers (piceasides) as well as the terpene α-longipinene may be suitable markers of low susceptibility for P. abies to Heterobasidion.

  • 144.
    Danielsson, Marie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Tracing induced stress sites in conifers by single needle analysesManuscript (preprint) (Other academic)
  • 145.
    Danielsson, Marie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kännaste, Astrid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindström, Anders
    School of Industrial Technology and Management, Dalarna University.
    Hellqvist, Claes
    Department of Ecology, Swedish University of Agricultural Sciences.
    Stattin, Eva
    School of Industrial Technology and Management, Dalarna University.
    Långström, Bo
    Department of Ecology, Swedish University of Agricultural Sciences.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Mini-seedlings of Picea abies are less attacked by Hylobius abietis than conventional ones: Is plant chemistry the explanation?2008In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 23, no 4, p. 299-306Article in journal (Refereed)
    Abstract [en]

    The pine weevil, Hylobius abietis (L.), is a major pest in conifer reforestation areas in the Palaearctic region. Size and chemistry of the seedlings may explain the damage rates in plantations. The performance of 10-week containerized seedlings (mini-seedlings) was compared with 1-year-old conventional seedlings of Norway spruce, Picea abies (L.), in a field experiment in central Sweden. After 2 years the weevil damage was lower for the mini-seedlings than for the conventional seedlings (3.5 vs 55%). After 3 years, the overall survival was 82 and 75%, respectively. Weevil damage was the main cause of mortality for conventional seedlings, whereas mini-seedlings mainly died from drought. Volatiles of the two seedling types were compared by solid-phase microextraction-gas chromatography -mass spectrometry (SPME-GC-MS). Unwounded mini-seedlings and conventional seedlings differed in their compositions of monoterpenes and sesquiterpenes. Miniseedlings mainly emitted limonene, known to be repellent to the pine weevil. When wounded, green leaf volatiles were released by mini-seedlings while the pine weevil attractant alpha-pinene was released by conventional seedlings. Volatiles may partly explain the mini-seedlings' resistance against weevil attack. Further studies are needed to clarify how long this miniseedling effect remains.

  • 146.
    Danielsson, Marie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lunden, Karl
    Elfstrand, Malin
    Hu, Jiang
    Zhao, Tao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Arnerup, Jenny
    Ihrmark, Katarina
    Swedjemark, Gunilla
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stenlid, Jan
    Chemical and transcriptional responses of Norway spruce genotypes with different susceptibility to Heterobasidion spp. infection2011In: BMC Plant Biology, ISSN 1471-2229, E-ISSN 1471-2229, Vol. 11, p. 154-Article in journal (Refereed)
    Abstract [en]

    Background: Norway spruce [Picea abies (L.) Karst.] is one of the most important conifer species in Europe. The wood is economically important and infections by wood-rotting fungi cause substantial losses to the industry. The first line of defence in a Norway spruce tree is the bark. It is a very efficient barrier against infection based on its mechanical and chemical properties. Once an injury or an infection is recognized by the tree, induced defences are activated. In this study we examined transcriptional response, using 454-sequencing, and chemical profiles in bark of Norway spruce trees with different susceptibility to Heterobasidion annosum s.l. infection. The aim was to find associations between the transcriptome and chemical profiles to the level of susceptibility to Heterobasidion spp. in Norway spruce genotypes. Results: Both terpene and phenol compositions were analysed and at 28 days post inoculation (dpi) high levels of 3-carene was produced in response to H. annosum. However, significant patterns relating to inoculation or to genotypes with higher or lower susceptibility could only be found in the phenol fraction. The levels of the flavonoid catechin, which is polymerized into proanthocyanidins (PA), showed a temporal variation; it accumulated between 5 and 15 dpi in response to H. annosum infection in the less susceptible genotypes. The transcriptome data suggested that the accumulation of free catechin was preceded by an induction of genes in the flavonoid and PA biosynthesis pathway such as leucoanthocyanidin reductase. Quantitative PCR analyses verified the induction of genes in the phenylpropanoid and flavonoid pathway. The qPCR data also highlighted genotype-dependent differences in the transcriptional regulation of these pathways. Conclusions: The varying dynamics in transcriptional and chemical patterns displayed by the less susceptible genotypes suggest that there is a genotypic variation in successful spruce defence strategies against Heterobasidion. However, both high levels of piceasides and flavonoids in the less susceptible genotypes suggested the importance of the phenolic compounds in the defence. Clearly an extended comparison of the transcriptional responses in the interaction with Heterobasidion between several independent genotypes exhibiting reduced susceptibility is needed to catalogue mechanisms of successful host defence strategies.

  • 147.
    Danielsson, Marie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lundén, Karl
    Arnerup, Jenny
    Hu, Jiang
    Zhao, Tao
    Swedjemark, Gunilla
    Elfstrand, Malin
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Stenlid, Jan
    Chemical and transcriptional responses of Norway spruce clones with different susceptibility to Heterobasidion spp. infectionManuscript (preprint) (Other academic)
  • 148. de Boer, Hugo
    et al.
    Vongsombath, Chanda
    Palsson, Katinka
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Bjork, Lars
    Jaenson, Thomas G. T.
    Botanical Repellents and Pesticides Traditionally Used Against Hematophagous Invertebrates in Lao People's Democratic Republic: A Comparative Study of Plants Used in 66 Villages2010In: Journal of medical entomology, ISSN 0022-2585, E-ISSN 1938-2928, Vol. 47, no 3, p. 400-414Article in journal (Refereed)
    Abstract [en]

    Hematophagous parasites such as leeches, ticks, mites, lice, bedbugs, mosquitoes, and myiasis-producing fly larvae are common health problems in Lao People's Democratic Republic. Several arthropod-borne infections, e.g., malaria, dengue fever, and Japanese encephalitis, are endemic there. Effective vector control methods including the use of pesticides, insecticide-treated bed nets, and synthetic and plant-based repellents are important means of control against such invertebrates and the pathogens they may transmit or directly cause. In this study, we documented traditional knowledge on plants that are used to repel or kill hematophagous arthropods, including mosquitoes, bedbugs, human lice, mites and ticks, fly larvae, and blood-sucking leeches. Structured interviews were carried out in 66 villages comprising 17 ethnic groups, covering a range of cultures, throughout Lao People's Democratic Republic. A total of 92 plant species was recorded as traditional repellents (including plants for pesticidal usages) in 123 different plant-ectoparasite combinations. The number and species of plants, and animal taxa repelled (or killed) per plant species differed per region, village, and ethnic group. Traditional use was confirmed in the scientific literature for 74 of these plant species, and for an additional 13 species using literature on closely related species. The use of botanical repellents and pesticides from many plant species is common and widespread in the Lao countryside. In the future, the identification of the active components in certain plants to develop more optimal, inexpensive repellents, insecticides, acaricides, or antileech compounds as alternatives to synthetic repellents/pesticides against blood-feeding insects, ticks, mites, and leeches is warranted.

  • 149. De Prins, Jurate
    et al.
    Mozuraitis, Raimondas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    A new species of Phyllonorycter (Lepidoptera: Gracillariidae) from Kenya discovered by using the sex attractant Z8-tetradecen-1-yl acetate2006In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, no 1124, p. 55-68Article in journal (Refereed)
    Abstract [en]

    Phyllonorycter obandai, new species, was discovered in Kenya using traps baited with the synthetic sex attractant Z8-tetradecen-1-yl acetate. This is the first species of Phyllonorycter recorded from Kenya. External morphological features of adult males, along with their genitalia are described and illustrated from specimens attracted to the traps. A distribution map for P. obandai is also presented.

  • 150. De Prins, Jurate
    et al.
    Mozuraitis, Raimondas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lopez-Vaamonde, Carlos
    Rougerie, Rodolphe
    Sex attractant, distribution and DNA barcodes for the Afrotropical leaf-mining moth Phyllonorycter melanosparta (Lepidoptera: Gracillariidae))2009In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, no 2281, p. 53-67Article in journal (Refereed)
    Abstract [en]

    The sex attractant for Phyllonorycter melanosparta (Meyrick, 1912) has been determined as (10E)-dodec-10-en-1-yl acetate and (10E)-dodec-10-en-1-ol combined in a ratio 10:1. The distribution of this species in Eastern Africa is updated and its presence in Kenya is recorded for the first time. We discuss the taxonomic status of P. melanosparta with reference to three character sets: semiochemicals, morphological and molecular characters (DNA barcodes). This combination of characters is also proposed as a new approach to study the diversity and phylogeny of Phyllonorycter in the Afrotropical region.

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