Ternary blends based on two donor and one acceptor components provide a potentially effective route in surpassing the theoretical efficiencies of binary-blend solar cells. A new ternary system was developed to produce ternary blend solar cells[1]. This system contains a donor–acceptor-type polymer with high Voc[2]，novel small molecules with suitable energy levels and phenyl-C-butyric acid methyl ester (acceptor)[3]. Two donors can be employed in ternary solar cells at any composition, which enhanced power conversion efficiency (PCE) from 6.85 % to 8.40 % compared with that of binary systems based on polymer donor. The results revealed that the appropriate blending ratio of small molecules in polymer binary system could offer multiple benefits and generate synergistic effects, such as film morphology modification, charge carrier mobility improvement, and induction of exciton dissociation at the donor–acceptor interface, thereby increasing the Voc, Jsc, and FF values of the devices.
References: [1]Y. Zhang, D. Deng, K. Lu*, J. Zhang, B. Xia, Y. Zhao, J. Fang, Z. X. Wei*, Adv. Mater.2014, DOI:10.1002/adma.201404902. [2]K. Lu, J. Fang, H. Yan, X. W. Zhu, Y. P. Yi*, Z. X. Wei*, Org. Electron. 2013, 14, 2652. [3]D. Deng, Y. Zhang, L. Yuan, C. He*, K. Lu*, Z. X. Wei*, Adv. Energy Mater.
2014. 4, 1400538.