A paper written by Daobin Yang (Kido/Sasabe Lab), exchange student from Sichuan University of China, has been accepted by Organic Electronics (IF: 3.827).

Two different donor subunits substituted unsymmetrical squaraines for solution-processed small molecule organic solar cells
By Daobin Yang, Yan Jiao, Yan Huang, Taojun Zhuang, Lin Yang, Zhiyun Lu, Xuemei Pu, Hisahiro Sasabe, and Junji Kido, Organic Electronics, in press.

Abstract: Two unsymmetrical squaraines (USQs) with different donor (D) subunits as photovoltaic materials, namely USQ-11 and USQ-12, were designed and synthesized to investigate the effect of different D subunits on the optoelectronic properties of USQs for the first time. The two USQs compounds were characterized for optical, electrochemical, quantum chemical and optoelectronic properties. By changing the two different D subunits attached to the squaric acid core from 2,3,3-trimethylindolenine to 2-methylbenzothiazole, the HOMO energy levels could be tuned with a stepping of 0.07 eV, and quite different solid state aggregations (H- or J-aggregation) were observed in the thin film by UV-Vis absorption spectra, which were attributed to their distinct steric effects and dipole moments. Solution-processed bulk-heterojunction small molecule organic solar cells fabricated with the USQ-11/PC71BM (1:5, wt%) exhibited extremely higher PCE (4.27 %) than that of the USQ-12/PC71BM (2.78 %). The much enhanced PCE should be attributed to the simultaneously improved Voc, Jsc and FF.

Related HP: http://oled.yz.yamagata-u.ac.jp/view.cgi?p=230