Theoretical Investigation on the Charge Transport Properties of 2,5-Di(cyanovinyl)-thiophene/furan with the Kinetic Monte Carlo Method

摘要

Exploring, designing, and synthesizing novel organic field-effect transistor(OFET) materials have kept an important and hot issue in organic electronics. In the current work, the charge transport properties for 2,5-di(cyanovinyl)thiophene/furan crystal associating two pentafluorophenyl units linked via the azomethine bond, CTE and CFE have been theoretically investigated by means of density functional theory(DFT) calculations coupled with the incoherent charge-hopping mechanism and the kinetic Monte Carlo simulation. Results show that these two compounds possess remarkably low-lying HOMO(–7.0 eV) and LUMO(–4.0 e V) levels, as well as large electron affinities(> 3.0 e V), which indicate their high stability exposed to air as promising OFET materials. However, the μh value at room temperature(T = 300 K) is predicted to be 2.058×10^(-7) cm^2·V^(-1)·s^(-1), and the μe is as low as 9.834×10^(-8) cm^2·V^(-1)·s^(-1) for CFT crystal. Meanwhile, these two values are 7.561 × 10^(-8) and 8.437 × 10^(-8) cm^2·V^(-1)·s^(-1) for the CFE crystal, respectively. Furthermore, the simulation of angle-dependent mobility in the a-b, a-c, and b-c crystal planes shows that the charge transport in CTE and CFE crystals is remarkably anisotropic, which maybe is helpful for the fabrication of high-performance OFET devices.