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.