Organic photovoltaic cells with copper (Ⅱ) tetra-methyl substituted phthalocyanine
Xu Zong-Xiang (许宗祥)a, Roy V. A. L.b
a Department of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China; b Center of Super Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
Abstract Efficient heterojunction organic photovoltaic (OPV) cells are fabricated based on copper tetra-methyl phthalocyanine (CuMePc) as donor and fullerene (C60) as acceptor. The power conversion efficiency of CuMePc/C60 OPV cell (2.52%) is increased by 88% compared with that of the non-peripheral substituted copper phthalocyanine (CuPc)/C60 OPV cell (1.34%). The introduction of methyl substituent leads to stronger π–π interaction of CuMePc (~ 3.5 Å) than that of CuPc (~ 3.8 Å). The efficiency improvement is attributed to the enhanced carrier mobility of CuMePc thin film (1.1×10-3 cm2/V·s) and better film morphology by introducing methyl groups into the periphery of CuPc molecule.
Fund: Project supported by the Special Funds for the Development of Strategic Emerging Industries in Shenzhen City, China (Grant No. JCYJ20120830154526537), Start-up Funding of the South University of Science and Technology of China, and the Strategic Research Grant of the City University of Hong Kong (Grant No. 7002724).
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