Giant photoluminescence enhancement in monolayer WS_2 by energy transfer from CsPbBr_3 quantum dots

Abstract

Monolayer (ML) transition metal dichalcogenides (TMDCs) are thought to be highly promising materials for the optoelectronic and nanophotonic applications. However, the low absorption cross section and photoluminescence (PL) quantum yield in such atomically thin layers restrict their applications. Considering that the energy transfer in a heterostructure can modulate TMDCs’ optical properties, a type I heterostructure geometry comprising ML TMDCs and lead halide perovskite quantum dots (QDs) has the potential to overcome these shortcomings. In this work, spin-coating the CsPbBr3 QDs on ML WS2 results in ~12.7 times enhancement in the PL intensity of ML WS2 at 295K. This giant enhancement is attributed to the energy transfer process from CsPbBr3 QDs to WS2 with a ~40% energy transfer efficiency and ~2 × 108 s−1 energy transfer rate. Besides, we observed that the internal quantum efficiency of ML WS2 is increased from 6.35% to 29.01%. The result demonstrates the feasibility of using perovskite QDs and ML TMDCs to form a type I heterostructure and improve the performance of the TMDC-based optoelectronic devices.