Disorder-Induced Localization With on-Device Tunability in Asymmetric Molecular Semiconductors.

Abstract

High-mobility organic semiconductors (OSCs) can potentially exhibit metallic carrier behaviors, and electron correlation-driven metal-insulator transition (MIT) has also been realized by tuning the carrier density. However, continuous Anderson transition has rarely been reported in OSCs, due to the difficulty of controllable disorder introduction and localization length tunability. Here we report a strategy of on-device disorder introduction in asymmetric molecular semiconductors that allows the realization of tunable carrier localization and Anderson MIT without a structural phase transition. The disorder can be introduced finely by co-regulating temperature and electric fields to obtain various disorder levels. The effectiveness of this strategy is further confirmed by the calculation of localization length and mean free path, both decreasing with the increased disorder level. This work provides an ideal testbed to investigate the nontrivial interplay of carrier transport property and disorder in disordered organic systems.