文献类型：期刊文献

英文题名：Cosensitization of D-A-π-A Quinoxaline Organic Dye: Efficiently Filling the Absorption Valley with High Photovoltaic Efficiency

作者：Pei, Kai[1,2];Wu, Yongzhen[1,2];Li, Hui[1,2];Geng, Zhiyuan[3];Tian, He[1,2];Zhu, Wei-Hong[1,2]

机构：[1]E China Univ Sci & Technol, Shanghai Key Lab Funct Mat Chem, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Inst Fine Chem, Collaborat Innovat Ctr Coal Based Energy I CCE, Shanghai 200237, Peoples R China;[3]Northwest Normal Univ, Gansu Key Lab Polymer Mat, Coll Chem & Chem Engn, Key Lab Ecoenvironm Related Polymer Mat,Minist Ed, Lanzhou 730070, Gansu, Peoples R China

年份：2015

卷号：7

期号：9

起止页码：5296

外文期刊名：ACS APPLIED MATERIALS & INTERFACES

收录：;EI(收录号：20151100639902);WOS:【SCI-EXPANDED(收录号:WOS:000350614600033)】；

基金：This work was supported by NSFC for Creative Research Groups (21421004) and Distinguished Young Scholars (21325625), NSFC/China, the Oriental Scholarship, National Major Scientific Technological Special Project (2012YQ15008709), and the Fundamental Research Funds for the Central Universities (WJ1416005).

语种：英文

外文关键词：dye-sensitized solar cells; cosensitization; quinoxaline pi-bridges; photovoltaic efficiency

摘要：In the efficient cosensitization, the pure organic sensitizers with high molecular extinction coefficients and long wavelength response are highly preferable since the dye loading amount for each dye in cosensitization is decreased with respect to single dye sensitization. A D-A-pi-A featured quinoxaline organic sensitizer IQ21 is specifically designed. The high conjugation building block of 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) is introduced as the pi bridge, instead of the traditional thiophene unit, especially in realizing high molecular extinction coefficients (up to 66 600 M-1 cm(-1)) and extending the light response wavelength. With respect to the reference dye IQ4, the slightly lower efficiency of IQ21 (9.03%) arises from the decrease of VOC, which offsets the gain in JSC. While cosensitized with a smaller D-p-A dye S2, the efficiency in IQ21 is further improved to 10.41% (J(SC) = 19.8 mA cm(-2), V-OC = 731 mV, FF = 0.72). The large improvement in efficiency is attributed to the well-matched molecular structures and loading amounts of both dyes in the cosensitization system. We also demonstrated that coabsorbent dye S2 can distinctly compensate the inherent drawbacks of IQ21, not only enhancing the response intensity of IPCE, making up the absorption defects around low wavelength region of IPCE, but also repressing the charge recombination rate to some extent.