Hot carrier dynamics in the BA2PbBr4/MoS2 heterostructure

Abstract

Herein, we investigated the carrier–phonon relaxation process in a two-dimensional (2D) BA₂PbBr₄ perovskite and its heterostructure with MoS₂. Energy transfer was observed in the van der Waals heterostructure of 2D perovskite and monolayer MoS₂, leading to enhancement in the photoluminescence intensity of MoS₂. Femtosecond pump–probe spectroscopy was used to study the carrier and lattice dynamics of pristine 2D materials and their heterostructure. A generalized two-temperature model was introduced to include competing effects of electron cooling in the rate equation of electron and lattice relaxation dynamics. The hot phonon bottleneck effect is more enhanced in the BA₂PbBr₄/MoS₂ heterostructure than in pristine BA₂PbBr₄, resulting in a longer electron relaxation time. By developing a heterostructure platform with 2D BA₂PbBr₄ and MoS₂ hybrid materials, this work provides a unique opportunity to understand and tailor carrier dynamics, interfacial coupling, and long-lived hot electrons, ultimately enhancing the efficiency of optoelectronic devices.