Defect-engineered MoS2 with extended photoluminescence lifetime for high-performance hydrogen evolution

Abstract

It has been reported that defects in molybdenum disulfide (MoS₂) enable the hydrogen evolution reaction (HER). The most widely employed method of argon-plasma treatment for defect generation suffers from poor material stability and loss of conductivity. Here, we report a new method to synthesize highly polycrystalline molybdenum disulfide MoS₂ bilayers with enhanced HER performance and material stability. This new method is based on metal organic chemical vapor deposition (MOCVD) followed by UV/ozone treatment to generate defects. The defect densities on MoS₂ were identified by the increase in lifetime (∼76%) and intensity (∼15%) in photoluminescence (PL) as compared to those of pristine MoS₂. Our fabrication and characterization methods can be further applied to optimize defect densities for catalytic effects in various transition metal dichalcogenide (TMDC) materials.