Study on interface engineering and chemical bonding of the ReS₂@ZnO heterointerface for efficient charge transfer and...

Rhenium sulfide (ReS₂) has emerged as a promising two-dimensional material, demonstrating broad-spectrum visible absorption properties that make it highly relevant for diverse optoelectronic applications. Manipulating and optimizing the pathway of photogenerated carriers play a pivotal role in enhancing the efficiency of charge separation and transfer in novel semiconductor composites. This study focuses on the strategic construction of a semiconductor heterostructure by synthesizing ZnO on vacancy-containing ReS₂ (V_Re-ReS₂) through chemical bonding processes. The ingeniously engineered built-in electric field within the heterostructure effectively suppresses the recombination of photogenerated electron-hole pairs. A direct and well-established interfacial connection between V_Re-ReS₂ and ZnO is achieved through a robust Zn-S bond. This distinctive bond configuration leads to enhanced nonlinear optical conversion efficiency, attributed to shortened carrier migration distances and accelerated charge transfer rates. Furthermore, theoretical calculations unveil the superior chemical interactions between Re vacancies and sulfide moieties, facilitating the formation of Zn-S bonds. The photoluminescence (PL) intensity is increased by the formation of V_Re-ReS₂ and ZnO heterostructure and the PL quantum yield of V_Re-ReS₂ is improved. The intricate impact of the Zn-S bond on the nonlinear absorption behavior of the V_Re-ReS₂@ZnO heterostructure is systematically investigated using femtosecond Z-scan techniques. The charge transfer from ZnO to ReS₂ defect levels induces a transition from saturable absorption to reverse saturable absorption in the V_Re-ReS₂@ZnO heterostructure. Transient absorption measurements further confirm the presence of the Zn-S bond between the interfaces, as evidenced by the prolonged relaxation time (τ₃) in the V_Re-ReS₂@ZnO heterostructure. This study offers valuable insights into the rational construction of heterojunctions through tailored interfacial bonding and surface/interface charge transfer pathways. These endeavors facilitate the modulation of electron transfer dynamics, ultimately yielding superior nonlinear optical conversion efficiency and effective charge regulation in optoelectronic functional materials.