Suppressed Nonradiative Recombination in 2D Reduced- Graphene- Oxide (rGO)-Wrapped 3D MoS2 Microflower

We present a comprehensive study on the synthesis and characterization of 2D reduced graphene oxide (rGO) encapsulated 3D Molybdenum disulfide (MoS2) nanocomposites, a promising semiconductor material with applications spanning electronic and optoelectronic domains. Through a facile two-step chemical synthesis, we successfully fabricated both pristine MoS2 (denoted as S1) and MoS2-rGO composites (termed S2), yielding distinctive flower-like microspheres comprised of folded nanosheets. Our temperature-dependent PL investigations unveiled pronounced mid-gap emission peaks within the UV (380-468 nm) and visible (490-550 nm) regions, indicative of excitonic behavior. Notably, the S2 composite exhibited enhanced PL intensity and extended carrier lifetimes across all studied temperatures, attributed to effective suppression of surface states via d-electron hopping. Complementary high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses further corroborated the presence of surface defects and d-electron hopping mechanisms, elucidating their pivotal roles in enhancing PL emission characteristics. This study offers valuable insights into the fundamental properties of MoS2-rGO nanocomposites, paving the way for tailored device design and applications.