title: Broad Bandgap D-A Copolymer Based on Bithiazole Acceptor Unit for Application in High-Performance Polymer Solar Cells with Lower Fullerene Content.
abstract: A new broad bandgap and 2D-conjugated D-A copolymer, PBDTBTz-T, based on bithienyl-benzodithiophene donor unit and bithiazole (BTz) acceptor unit, is designed and synthesized for the application as donor material in polymer solar cells (PSCs). The polymer possesses highly coplanar and crystalline structure with a higher hole mobility and lower HOMO energy level which is beneficial to achieve higher open circuit voltage (Voc ) of the PSCs with the polymer as donor. The PSCs based on PBDTBTz-T:PC71 BM blend film with a lower PC71 BM content of 40% demonstrate a power conversion efficiency (PCE) of 6.09% with a relatively higher Voc of 0.92 V. These results indicate that the lower HOMO energy level of the BTz-based D-A copolymer is beneficial to a high Voc of the PSCs. The polymer, with highly coplanar and crystalline structure, can effectively reduce the content of fullerene acceptor in the active layer and can enhance the absorption and PCE of the PSCs.
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Guo
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Guo
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Wanbin
authors.initials: W
authors.lastname: Li
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.
authors.forename: Maojie
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China.|Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Yongfang
authors.initials: Y
authors.lastname: Li
mesh_terms: D001735:Bithionol / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D012993:Solar Energy; D013876:Thiophenes / Q000737:chemistry
chemical_list: D037741:Fullerenes; D011108:Polymers; D013876:Thiophenes; D001735:Bithionol
keywords: 2D-conjugated D-A copolymers; bithiazole (BTz) acceptor units; bithienyl-benzodithiophenes; low fullerene content; polymer solar cells