Synthesis and Characterization of Conjugated Low Band-Gap Terpolymers Incorporating Carbazole for Photovoltaic Application
作者:Ki-Won Kim、Hyungjun Na、Won-Wook So、Sung Cheol Yoon、Won Suk Shin
DOI:10.1166/jnn.2012.5895
日期:2012.5.1
A series of photoactive conjugated low band-gap copolymer (CPSB) and terpolyemrs (TPSBCz-n, n = 1 to 4) based on N-alkyl carbazole, 4,4′-dialkyl dithienosilole, and bezothiadiazole were synthesized. The copolymer and terpolymers were built with the fraction of the carbazole unit varied for 0, 2.5, 5, 10 and 25 mol%. Among the mixtures, the composition of 25 wt% of terpolymer bearing 10 mol.% of the carbazole unit, TPSBCz-3, and 75 wt% of C71-PCBM found a power conversion efficiency of 0.86% with a open-circuit voltage of 0.59 V, the short-circuit current of 4.85 mA and fill factor of 0.30 under AM 1.5 spectral illumination. Our findings suggest that terpolymer bearing low concentration of carbazole lead to a high power conversion efficiency with improved the short-circuit current due to hole mobility enhancement effect of carbazole unit.
一系列基于N-烷基咔唑、4,4'-二烷基二噻吩硅和苯并噻二唑的光活性共轭低带隙共聚物(CPSB)和三聚物(TPSBCz-n,n=1到4)被合成。通过改变共聚物和三聚物中的咔唑单元的比例,设计了咔唑单元在0、2.5、5、10和25摩尔百分比的不同组合。在这些混合物中,含10摩尔百分比咔唑单元的三聚物TPSBCz-3占25重量百分比,以及C71-PCBM占75重量百分比的混合物在AM 1.5光谱照射下的能量转换效率达到了0.86%,开路电压为0.59 V,短路电流为4.85 mA,填充因子为0.30。我们的研究结果表明,含低浓度咔唑的三聚物由于咔唑单元的空穴迁移增强效应,能显著提高短路电流,从而提升能量转换效率。