Two wide-bandgap fluorine-substituted benzotriazole based terpolymers for efficient polymer solar cells. (August 2018)

• Record Type: Journal Article
• Authors: Qi, Feng; Song, Jiali; Xiong, Wentao; Huo, Lijun; Sun, Xiaobo; Sun, Yanming
• Is Part Of: Dyes and pigments. Volume 155(2018)
• Page Start: 126
• Page End: 134
• Publication Date: 2018-08
• Subjects: Terpolymer -- Synergetic effect -- Fluorine-substituted benzotriazole -- Polymer solar cells; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2018.03.013
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: In this work, the fluorine substituted benzotriazole (FBTz) unit is introduced into terpolymers for the first time. FBTz as an acceptor unit was added to the terpolymers of PTT-FBTz and PTTz-FBTz, in which the bithiophene (biTh) unit is used as the donor unit and thieno[3, 2- b ]thiophene (TT) or thiazolo[5, 4- d ]thiazole (TTz) is adopted as a third component, respectively. Compared to PTT-FBTz with TT as the third component, PTTz-FBTz with TTz showed pronounced aggregated shoulder peaks both in solution and film absorption spectra. Electrochemical cyclic voltammetry (CV) shows PTTz-FBTz possesses both lower HOMO/LUMO level than PTT-FBTz due to the higher electronegativity of nitrogen atoms in TTz unit. Subsequently, the bulk-heterojunction polymer solar cells (PSCs) based on PTTz-FBTz show a higher power conversion efficiency of 7.03%, which is much higher than those of PTT-FBTz based devices (PCE = 2.63%). The enhancement of photovoltaic performance based on PTTz-FBTz is mainly attributed to the deeper highest occupied molecular orbital (HOMO) level, higher carrier transport and better molecular packing. Graphical abstract: Highlights: Fluorine substituted benzotriazole (FBTz) unit is firstly introduced to the terpolymers. D1-A1-D1-A2 structure is more efficient strategy in constructing FBTz based photovoltaic terpolymer. PSCs based on PTTz-FBTz shows a high PCE of 7.03% with a high V oc of 0.88 V.