Development of s-tetrazine-based polymers for efficient polymer solar cells by controlling appropriate molecular aggregation. (December 2019)

• Record Type: Journal Article
• Authors: Peng, Lini; Yu, Yufu; Lu, Jie; He, Pingxiang; Wang, Guo; Huang, Meihua; Zhao, Bin; Pei, Yong; Tan, Songting
• Is Part Of: Dyes and pigments. Volume 171(2019)
• Publication Date: 2019-12
• Subjects: Polymer solar cells -- s-Tetrazine -- Side-chain engineering -- Molecular aggregation; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2019.107717
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract : Two conjugated polymersPTTTz andPHTTz have been designed and synthesized by introducing s -tetrazine as electron-withdrawing moieties. Compared withPTTTz with 2-octyldodecyl-substituted tetrathiophene derivative as electron-donating moieties, PHTTz with hexyl- and 2-octyldodecyl-substituted hexathiophene derivative possesses relatively lower molecular coplanarity, larger stacking distance but more orderly molecular stacking, more red-shifted absorption, more suitable microphase separation, more efficient exciton dissociation, higher hole mobility, which lead to higher short-circuit current density (11.54 mA cm −2 ), fill factor (69.0%) and power conversion efficiency (PCE = 6.69%) values in PSCs. ThePTTTz -based PSC shows an open circuit voltage of 1.02 V for its lower-ling HOMO energy level though the PCE of the PSC is only 5.16%. Moreover, the ternary PSC basedPHTTz /PC71 BM/ITIC exhibits a higher PCE value of 7.88% than the binary PSCs for more efficient exciton dissociation and complementary absorption spectrum in ternary blend film, which is one of the highest PCE values in s -tetrazine-based polymers. Graphical abstract: Image 1 Highlights: s -tetrazine-based polymer achieves a V OC of 1.02 V. PHTTz shows the best photovoltaic performance in s -tetrazine-based polymers. The effects of the chemical structure on molecular aggregation and photovoltaic properties are studied.