Difluorobenzimidazole-decorated helical perylene diimide dimers for high-performance n-type organic field-effect transistors

Abstract

The vinylene-bridged helical perylene diimide dimer (PDI2) and its derivatives have manifested great promise for applications in organic photovoltaics (OPVs). However, their performance in organic field-effect transistors (OFETs) has been somewhat overlooked and is underdeveloped. Here two PDI2 derivatives, namely MBI-PDI2 and FMBI-PDI2, were constructed by installation of a benzimidazole or difluorobenzimidazole group at one of the four imide groups. Compared with the parent PDI2, both MBI-PDI2 and FMBI-PDI2 exhibit bathochromic shifts of the absorption maxima and deeper lowest unoccupied molecular orbital (LUMO) energy levels. Solution processed OFETs using these two compounds as well as PDI2 were demonstrated and a remarkable electron mobility of up to 0.13 cm² V⁻¹ s⁻¹ was achieved for FMBI-PDI2.