Heteroepitaxial Strain Engineering and Interfacial Energy Transfer Boosting Optoelectronic Properties in C₆₀/WS₂ van...

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.