文献类型：期刊文献

英文题名：D-A-π-A featured sensitizers by modification of auxiliary acceptor for preventing "trade-off'' effect

作者：Zhu, Haibo[1,2];Liu, Bo[3];Liu, Jingchuan[1,2];Zhang, Weiwei[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, Collaborat Innovat Ctr Coal Based Energy i CCE, 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]Hebei Normal Univ, Coll Chem & Mat Sci, Shijiazhuang 050023, Peoples R China

年份：2015

卷号：3

期号：26

起止页码：6882

外文期刊名：JOURNAL OF MATERIALS CHEMISTRY C

收录：;EI(收录号：20152700988906);WOS:【SCI-EXPANDED(收录号:WOS:000356965300035)】；

基金：This work was supported by NSFC for Creative Research Groups (21421004) and Distinguished Young Scholars (21325625), NSFC/China, the Oriental Scholarship, Science and Technology Commission of Shanghai Municipality (15XD1501400), and the Fundamental Research Funds for the Central Universities (WJ1416005).

语种：英文

外文关键词：Photocurrents - Dye-sensitized solar cells - Economic and social effects - Grafting (chemical) - Benzene - Styrene

摘要：Four D-A-pi-A motif organic sensitizers (IQ9, IQ10, IQ11 and IQ12) in the absence or presence of thiophene substituents grafted onto the auxiliary acceptor of a quinoxaline unit have been developed for dye sensitized solar cells (DSSCs). Upon changing the p-linker from benzene to thiophene, the photocurrent (J(SC)) of IQ10 increases around 2-fold, and the photovoltage (V-OC) decreases by 52 mV compared to that of IQ9. It is attributed to the fact that compared with the benzene linker, the thiophene conjugated bridge in dye IQ10 induces a small twist in the molecular planarity, thus resulting in the high light-harvesting capability (beneficial to J(SC)) and high charge recombination (unbeneficial to V-OC). To prevent this "trade-off'' effect between photocurrent and photovoltage, the building block of 2,3-dithienylquinoxaline as an auxiliary unit is specifically incorporated, which brings forth several advantages such as distinctly extending the light-harvesting region, increasing molar absorption coefficients, and blocking the dye self-aggregation to reduce charge recombination. Remarkably, dye IQ12 exhibits a beneficial balance between J(SC) (17.97 mA cm(-2)) and V-OC (715 mV), along with a promising photovoltaic efficiency of 8.76%, much better than the corresponding dyes IQ9 (2.91%), IQ10 (7.75%) and IQ11 (6.56%). As demonstrated, the two twisted thiophene groups grafted onto the quinoxaline unit facilitate the resulting compact sensitizer layer to effectively overcome the charge recombination drawbacks in V-OC arising from the thiophene pi-bridge linker, providing a rational molecular engineering to pursue the synergistic enhancement in the photocurrent and photovoltage for highly efficient organic sensitizers.