A Benzo[1, 2‐b:4, 5‐c′]Dithiophene‐4, 8‐Dione‐Based Polymer Donor Achieving an Efficiency Over 16%. Issue 10 (29th January 2020)

• Record Type: Journal Article
• Authors: Chao, Pengjie; Chen, Hui; Zhu, Yulin; Lai, Hanjian; Mo, Daize; Zheng, Nan; Chang, Xiaoyong; Meng, Hong; He, Feng
• Is Part Of: Advanced materials. Volume 32:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-29
• Subjects: benzo[1, 2‐b:4, 5‐c′]dithiophene‐4, 8‐dione -- donor polymers -- nonfullerene solar cells -- thieno[3, 4‐b]thiophene; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201907059
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: It is of great significance to develop efficient donor polymers during the rapid development of acceptor materials for nonfullerene bulk‐heterojunction (BHJ) polymer solar cells. Herein, a new donor polymer, named PBTT‐F, based on a strongly electron‐deficient core (5, 7‐dibromo‐2, 3‐bis(2‐ethylhexyl)benzo[1, 2‐ b :4, 5‐ c ′]dithiophene‐4, 8‐dione, TTDO), is developed through the design of cyclohexane‐1, 4‐dione embedded into a thieno[3, 4‐ b ]thiophene (TT) unit. When blended with the acceptor Y6, the PBTT‐F‐based photovoltaic device exhibits an outstanding power conversion efficiency (PCE) of 16.1% with a very high fill factor (FF) of 77.1%. This polymer also shows high efficiency for a thick‐film device, with a PCE of ≈14.2% being realized for an active layer thickness of 190 nm. In addition, the PBTT‐F‐based polymer solar cells also show good stability after storage for ≈700 h in a glove box, with a high PCE of ≈14.8%, which obviously shows that this kind of polymer is very promising for future commercial applications. This work provides a unique strategy for the molecular synthesis of donor polymers, and these results demonstrate that PBTT‐F is a very promising donor polymer for use in polymer solar cells, providing an alternative choice for a variety of fullerene‐free acceptor materials for the research community. Abstract : Through a strategy of embedding cyclohexane‐1, 4‐dione into the thieno[3, 4‐ b ]thiophene unit, a highly electron‐deficient core (TTDO) is synthesized, and the corresponding donor polymer (PBTT‐F) is also developed. The nonfullerene photovoltaic device based on this new donor polymer exhibits an outstanding PCE of 16.1% with a very high fill factor of 77.1%, which demonstrates it a very promising donor for high‐performance solar cells.