Bandgap renormalization in monolayer MoS_2 on CsPbBr_3 quantum dot via charge transfer at room temperature

TL;DR

This study demonstrates significant room-temperature bandgap renormalization in monolayer MoS_2 on CsPbBr_3 quantum dots due to charge transfer, enabling potential applications in optoelectronic devices.

Contribution

It reveals the largest observed bandgap renormalization at room temperature in monolayer MoS_2 via charge transfer with quantum dots, highlighting a new pathway for device engineering.

Findings

Bandgap in heterostructure red-shifted by 84 meV at room temperature

Bandgap renormalization saturates with increased pump fluence

Renormalization magnitude inversely related to Thomas-Fermi screening length

Abstract

Many-body effect and strong Coulomb interaction in monolayer transition metal dichalcogenides lead to shrink the intrinsic bandgap, originating from the renormalization of electrical/optical bandgap, exciton binding energy, and spin-orbit splitting. This renormalization phenomenon has been commonly observed at low temperature and requires high photon excitation density. Here, we present the augmented bandgap renormalization in monolayer MoS_2 anchored on CsPbBr_3 perovskite quantum dots at room temperature via charge transfer. The amount of electrons significantly transferred from perovskite gives rise to the large plasma screening in MoS_2. The bandgap in heterostructure is red-shifted by 84 meV with minimal pump fluence, the highest bandgap renormalization in monolayer MoS_2 at room temperature, which saturates with further increase of pump fluence. We further find that the magnitude of bandgap renormalization inversely relates to Thomas-Fermi screening length. This provides plenty of room to explore the bandgap renormalization within existing vast libraries of large bandgap van der Waals heterostructure towards practical devices such as solar cells, photodetectors and light-emitting-diodes.