Heteroepitaxial Strain Engineering and Interfacial Energy Transfer Boosting Optoelectronic Properties in C60/WS2 van der Waals Heterostructures

Abstract

Engineered van der Waals (vdW) heterostructures, combining molecular semiconductors and atomically flat nanomaterials, offer vast opportunities to tailor optoelectronic properties at heterointerfaces. Here, the heteroepitaxial assembly of C60 molecules on monolayer tungsten disulfide (ML-WS2), where an anisotropic compression strain within the C60 lattice at the heterointerface induces the formation of 1D polymeric C60 strings and activates otherwise symmetry-forbidden S1 → S0 optical transitions, is reported. This, coupled with interfacial energy transfer from ML-WS2 to C60, results in a remarkable 310% enhancement in the PL intensity compared to disordered C60 aggregates. The resulting C60/ML-WS2 transistors exhibit superior electrical and optoelectronic performance, achieving a charge carrier mobility of 10.4 cm2 V−1 s−1, facilitated by an ultralow 230 meV contact barrier with Au electrodes. These devices demonstrate a superior photoresponsivity of 46.4 A W−1 and a detectivity of 3.6 × 1012 Jones, greatly outperforming pristine ML-WS2 counterpart devices.