Abstract
Abstract
Transition metal dichalcogenides (TMDCs) have received much attention for optoelectronic applications because of their band gap transition from indirect to direct as they decrease from multilayer to monolayer. Recent studies have experimented with the use of photochromic molecules to optically control the charge transport of two-dimensional (2D) TMDCs. In this work, a numerical study using density functional theory has been performed to test the possibility to control the optical property of 2D TMDC monolayers with various photochromic molecules. When the photochromic molecule’s highest occupied molecular orbital (HOMO) or lowest unoccupied molecular orbital (LUMO) energy levels are within the band gap of 2D TMDC monolayers, holes or electrons will transport to the photochromic molecules, resulting in the reduction of excitons in the 2D TMDC monolayers. The reduced optical response can be recovered by going through reverse isomerization of the photochromic molecules. Molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) monolayers were tested with various photochromic molecules including azobenzene, spiropyran, and diarylethenes (DAE 2 ethyl, DAE 5 ethyl, DAE 5 methyl). The systematic study presented in this work displays that MoS2-Spiropyran and every diarylethene derivative used in this study except MoS2-DAE 5 methyl exhibited photo-switchable behavior.