A novel 9H-indeno[1, 2-b]pyrazine-2, 3-dicarbonitrile end group for an efficient non-fullerene small molecule acceptor. Issue 32 (6th August 2019)

• Record Type: Journal Article
• Authors: Gao, Wei; Zhang, Miao; Chen, Zhanxiang; Liu, Xiaohui; Zheng, Kailu; Zhong, Cheng; Zhang, Fujun; Yang, Chuluo
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 32(2019)
• Page Start: 10111
• Page End: 10118
• Publication Date: 2019-08-06
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9tc01214a
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : A novel 9 H -indeno[1, 2- b ]pyrazine-2, 3-dicarbonitrile end group provides PBDB-T:BTOIPC-based OSCs with a PCE of 9.31% with an FF close to 70% and a low energy loss of 0.57 eV. Abstract : For acceptor–donor–acceptor (A–D–A) type non-fullerene small molecule acceptors (NF-SMAs), the electron-deficient active methylene end groups are pivotal for adjusting their properties and photovoltaic performances. However, a limited variety of end groups is not conducive to the full development of organic solar cells (OSCs) based on NF-SMAs. Herein, we developed a novel 9 H -indeno[1, 2- b ]pyrazine-2, 3-dicarbonitrile (IPC) end group and applied it into the design and synthesis of NF-SMAs called BTOIPC. BTOIPC with potential intramolecular CN⋯S interactions showed a planar conformation and small torsion angle. The strong electron-withdrawing ability of IPC endowed BTOIPC with a low optical bandgap ( E optg of 1.45 eV) and suitable HOMO and LUMO energy levels, similar to those of BT-IC. OSCs based on PBDB-T:BTOIPC achieved a power conversion efficiency (PCE) of 9.31% with a fill factor (FF) close to 70% and an energy loss ( E loss ) of 0.57 eV, which are comparable with those of the reported BT-IC. The advantageous features of the PBDB-T:BTOIPC bulk-heterojunction layer, such as high and balanced carrier mobility, good exciton dissociation, minor charge recombination and uniform morphology, contributed together to the good performance of IPC-based SMA. These results implied that IPC is a potential end group for NF-SMAs, and the modifiable structure of IPC gives IPC-based SMAs an ability to realize higher PCE in OSCs.