Tunable Excitation-Dependent Photoluminescences Using Energy Gap Regulating Photogenerated Electrons Injection Rate from Excited TiO2 Nanoparticles to MoS2 Nanosheets

Abstract

Control of the photogenerated electrons transfer rate from TiO₂ nanoparticles to MoS₂ nanosheets is an effective method for modulating the optical property of 2‒3 layers MoS₂ nanosheets. In this paper, core-shell structure MoS₂/polyvinyl benzyl mercaptan sub-microspheres (PS) with vertical 2‒3 layers MoS₂ nanosheets on the PS surface were prepared via solvothermal process. Core-shell structure MoS₂/PS microspheres show excitation-dependent photoluminescence. It is worth noting excitation- dependent photoluminescences can be tuned via a TiO₂ nanoparticles doping technique. With decreasing sizes of doping TiO₂ nanoparticles from 10.1 to 2.8 nm the intensities of the excitation- dependent photoluminescence (PL) were drastically enhanced approximately 1.2‒3.2 times and the average PL lifetimes are prolonged from 131 to 344 ps. The experimental results provide strong evidence with respect to control of the band energies, that is one of effective methods to accelerate photogenerated electrons transfer from excited TiO₂ nanoparticles to MoS₂ nanosheets for controlling the optical properties of 2‒3 layers MoS₂ nanosheets.