A polymer acceptor containing the B←N unitfor all-polymer solar cells with 14% efficiency. Issue 37 (9th September 2021)

• Record Type: Journal Article
• Authors: Wang, Yinghui; Wang, Ning; Yang, Qingqing; Zhang, Jidong; Liu, Jun; Wang, Lixiang
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 37(2021)
• Page Start: 21071
• Page End: 21077
• Publication Date: 2021-09-09
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta06041d
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A new polymer acceptor is designed by copolymerizing a small molecular acceptor with an electron-accepting building block based on the B←N unit. The all polymer solar cell with the polymer acceptor shows a power conversion efficiency of 14.3%. Abstract : The development of all polymer solar cells (all-PSCs) is limited by the lack of polymer acceptors. An effective strategy to design high-efficiency polymer acceptors is to copolymerize small molecular acceptors with electron-rich linking units. In this work, we develop a new polymer acceptor by copolymerizing a small molecular acceptor with an electron-deficient linking unit based on the boron–nitrogen coordination bond (B←N). The incorporation of B←N into the polymer acceptor downshifts the LUMO/HOMO energy levels of the polymer by ca. 0.1 eV, and thus facilitates photo-induced hole transfer from the polymer acceptor to polymer donor. The all-PSC device based on the polymer acceptor containing B←N exhibits a power conversion efficiency (PCE) of 14.3%, which is much higher than that of the control polymer acceptor without B←N (PCE = 7.2%). This is attributed to the improved phase separation morphology and the facilitated photo-induced hole transfer of the active layer based on the polymer acceptor containing B←N. These results suggest that B←N based building blocks with electron-deficient properties are promising to design high-performance polymer acceptors.