Efficient and Layer-Dependent Exciton Pumping across Atomically Thin Organic-Inorganic Type-I Heterostructures.

Abstract

The fundamental light-matter interactions in monolayer transition metal dichalcogenides might be significantly engineered by hybridization with their organic counterparts, enabling intriguing optoelectronic applications. Here, atomically thin organic-inorganic (O-I) heterostructures, comprising monolayer MoSe₂ and mono-/few-layer single-crystal pentacene samples, are fabricated. These heterostructures show type-I band alignments, allowing efficient and layer-dependent exciton pumping across the O-I interfaces. The interfacial exciton pumping has much higher efficiency (>86 times) than the photoexcitation process in MoSe₂ , although the pentacene layer has much lower optical absorption than MoSe₂ . This highly enhanced pumping efficiency is attributed to the high quantum yield in pentacene and the ultrafast energy transfer between the O-I interface. Furthermore, those organic counterparts significantly modulate the bindings of charged excitons in monolayer MoSe₂ via their precise dielectric environment engineering. The results open new avenues for exploring fundamental phenomena and novel optoelectronic applications using atomically thin O-I heterostructures.