Molecular design direction of organic spacer cations for low-dimensional organic–inorganic hybrid perovskite thin film transistors

Abstract

Organic spacer cations in low-dimensional organic–inorganic hybrid perovskites (LDPVKs) significantly affect the performance of perovskite materials and devices. Herein, we systematically examine the effects of four distinct organic spacer cations on the properties of materials and perovskite thin film transistors (TFTs). Our study explores the consequences of varying chain lengths, including butylamine (BA) and octylamine (OA), and also considers the impact of incorporating benzene rings, such as phenethylamine (PEA), as well as the influence of fluorine-substituted benzene ring side chains, as represented by fluorine-substituted phenethylamine (FPEA), within these organic spacer cations. The results show that long-chain organic cations such as alkyl-chain cations improve the stability of TFTs but does not improve its field effect mobility. Because it provides π-π stacking, the benzene ring cation improves the carrier mobility performance of LDPVKs. This significantly improves the electrical performance and stability of LDPVK TFTs, affording a field-effect mobility of 7.47 cm2/(V·s) and the threshold voltage difference between the positive and negative sweep (ΔVTH) of 0.25 V. Therefore, when designing provide a molecular design direction for selecting organic spacer cations in low-dimensional for organic–inorganic hybrid perovskites, various factors should be considered to optimized. This work study guides the designing LDPVKs and improving the performances of field-effect devices in the future.