Tunable interlayer coupling in twisted 2D organic--inorganic heterostructure

Abstract

In two-dimensional (2D) organic–inorganic (O-I) heterostructures, interlayer coupling has emerged as a design parameter for engineering their electronic and optoelectronic properties, essential for designing future excitonic and optoelectronic devices. However, the further exploration of interlayer couplings is limited by their weak strength and ineffective tuning strategies, due to the inconsistent material quality and the bulky size of organic counterparts. Here, we integrate 2D pentacene single crystals with monolayer MoS2 to achieve strong interlayer coupling and effective tuning through a twisting method. We confirm this strong coupling through calculated lower interlayer spacing (∼2.70 Å), high charge transfer efficiency (∼61%), and a high coupling strength of ∼2.72 at a twist angle of ∼32 deg. Both density functional theory calculations and experimental results demonstrate the remarkable electrical control over interlayer couplings by adjusting electrical band alignments. This control over interlayer couplings helps to untangle the diffusion of neutral excitons and trions, which have diffusion lengths of ∼1.95 and 0.93 μm, respectively. Our results underscore the significant tunability of interlayer couplings and relaxations within O-I systems via twist angles, offering avenues for developing high-performance vertical transistors, logic devices, photodetectors, and photovoltaic devices Show more