Photovoltaic Devices Prepared through a Trihydroxy Substitution Strategy on an Unsymmetrical Squaraine Dye. Issue 13 (1st February 2018)

• Record Type: Journal Article
• Authors: Wu, Jianglin; Si, Changfeng; Chen, Yao; Yang, Lin; Hu, Bin; Chen, Guo; Lu, Zhiyun; Huang, Yan
• Is Part Of: Chemistry. Volume 24:Issue 13(2018)
• Page Start: 3234
• Page End: 3240
• Publication Date: 2018-02-01
• Subjects: hole mobility -- hydroxy groups -- organic solar cells -- squaraines -- substituent effects; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201705140
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A series of unsymmetrical arene‐1, 3‐squaraine (USQ) derivatives with two, three, or four hydroxy (−OH) substituents, namely, USQ‐2‐OH, USQ‐3‐OH, orUSQ‐4‐OH, respectively, were designed and synthesized, and the effect of the number of hydroxy groups on the optoelectronic properties of USQs were investigated. Despite the three compounds having similar UV/Vis absorption and HOMO energy levels, solution‐processed bulk‐heterojunction (BHJ) small‐molecule organic solar cells withUSQ‐3‐OH as electron‐donor materials exhibit the highest power conversion efficiency of 6.07 %, which could be mainly attributed to the higher hole mobility and smaller phase separation. It is also noteworthy that the short‐circuit current ( J sc ) of theUSQ‐3‐OH ‐based device is as high as 14.95 mA cm −2, which is the highest J sc values reported for squaraine‐based BHJ solar cells to date. The results also indicate that more −OH substituents on squaraine dyes do not necessarily lead to better photovoltaic performance. Abstract : Squaring away symmetry : A series of unsymmetrical squaraine derivatives containing two, three, or four hydroxy substituents have been designed and synthesized to investigate the effect of the number of hydroxy groups on the optoelectronic properties of squaraine derivatives. Results reveal that the trihydroxy‐substituted unsymmetrical squaraine shows the best photovoltaic performance (see figure).