Influences of structural modification of naphthalenediimides with benzothiazole on organic field-effect transistor and non-fullerene perovskite solar cell characteristics

• Main Authors: Shaikh, Dada ., Ahmed Ali Said, Wang, Zongrui, Srinivasa Rao, Pedada, Bhosale, Rajesh S., Mak, Adrian M., Zhao, Kexiang, Zhou, Yu, Liu, Wenbo, Gao, Weibo, Xie, Jian, Bhosale, Sidhanath V., Bhosale, Sheshanath V., Zhang, Qichun
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2021
• Subjects: Engineering::Materials; Electron Transport; Naphthalenediimides; Organic Field-Effect Transistors; Perovskite; Solar Cells
• Online Access: https://hdl.handle.net/10356/154428
• Institution: Nanyang Technological University

Developing air-stable high-performance small organic molecule-based n-type and ambipolar organic field-effect transistors (OFETs) is very important and highly desirable. In this investigation, we designed and synthesized two naphthalenediimide (NDI) derivatives (NDI-BTH1 and NDI-BTH2) and found that introduction of 2-(benzo[d]thiazol-2-yl) acetonitrile groups at the NDI core position gave the lowest unoccupied molecular orbital (LUMO; -4.326 eV) and displayed strong electron affinities, suggesting that NDI-BTH1 might be a promising electron-transporting material (i.e., n-type semiconductor), whereas NDI-BTH2 bearing bis(benzo[d]thiazol-2-yl)methane at the NDI core with a LUMO of -4.243 eV was demonstrated to be an ambipolar material. OFETs based on NDI-BTH1 and NDI-BTH2 have been fabricated, and the electron mobilities of NDI-BTH1 and NDI-BTH2 are 14.00 × 10-5 and 8.64 × 10-4 cm2/V·s, respectively, and the hole mobility of NDI-BTH2 is 1.68 × 10-4 cm2/V·s. Moreover, a difference in NDI-core substituent moieties significantly alters the UV-vis absorption and cyclic voltammetry properties. Thus, we further successfully employed NDI-BTH1 and NDI-BTH2 as electron transport layer (ETL) materials in inverted perovskite solar cells (PSCs). The PSC performance exhibits that NDI-BTH2 as the ETL material gave higher power conversion efficiency as compared to NDI-BTH1, that is, NDI-BTH2 produces 15.4%, while NDI-BTH1 gives 13.7%. The PSC performance is comparable with the results obtained from OFETs. We presume that improvement in solar cell efficiency of NDI-BTH2-based PSCs is due to the well-matched LUMO of NDI-BTH2 toward the conduction band of the perovskite layer, which in turn increase electron extraction and transportation.