Solution‐Processed Bulk‐Heterojunction Photovoltaic Cells Based on Dendritic and Star‐Shaped D‐π‐A Organic Dyes |
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| Authors: | Jin‐Liang Wang Dr. Zhicai He Hongbin Wu Prof. Haibo Cui Yan Li Prof. Qihuang Gong Prof. Yong Cao Prof. Jian Pei Prof. |
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| Affiliation: | 1. Beijing National Laboratory for Molecular Sciences the Key Laboratories of Bioorganic Chemistry and Molecular, Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China), Fax: (+86)?10‐62758145;2. Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology the Key Laboratories of Specially Functional Materials of Ministry of Education, Guangzhou 510640 (China);3. State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, 100871 (China) |
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| Abstract: | A series of D ‐π‐A organic dendritic and star‐shaped molecules based on three various chromophores (i.e., the truxene nodes, triphenylamine moieties as the donor, and benzothiadiazole chromophore as the acceptor) and their corresponding model compounds are facilely developed. Their photophysical and electrochemical properties are investigated in detail by UV/Vis absorption and photoluminescent spectroscopy, and cyclic voltammetry. By changing the various conjugated spacers (i.e., single bond, double bond, and triple bond) among the three chromophores of dendritic series, their photophysical properties (that is, the one‐photon absorption range and two‐photon absorption cross‐section values) are effectively modulated. All D ‐π‐A conjugated oligomers show a broad and strong absorption band from 250 to 700 nm in thin films. Solution‐processed bulk‐heterojunction photovoltaic devices using our oligomer as donor and PCBM as acceptor are fabricated and measured. The power conversion efficiency of the devices based on our oligomers continuously increases from DBTTr to TRTD2A as a result of an increasing relative absorption intensity in longer wavelength region by changing the donor‐acceptor ratio and conjugated spacers between the donor and acceptor. The power conversion efficiency of the devices based on TRTD2A was 0.54 % under the illumination of AM 1.5 and 100 mW cm?2, which is the highest value recorded based on D ‐π‐A conjugated oligomers containing triphenylamine moieties and benzothiadiazole chromophores with truxene to date. |
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| Keywords: | conducting materials dendrimers molecular devices molecular electronics photophysics |
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