One pot and room temperature photochemical synthesis of high quantum yield NIR emissive Ag2S@Ag(In, Zn)S2 core-shells at the presence of air in water

Abstract

Here a new pathway for obtaining high Quantum Yield emission AgInS2 nanoparticles in water using defect engineering at air atmosphere is proposed. Ag2S@AgInS2 nanoparticles with zinc as both doping and alloying agent were synthesized systematically using a room temperature photochemical approach in air. 3-mercaptipropionic acid (MPA) was introduced as efficient capping agent in water. The high nucleation rate of Ag-S compare to In-S was the innovative key in the formation of core-shells using a one pot method. Zn insertion was found to have synergistic effect on controlling the growth rate and emissive defect states creation in the final product. TEM and XRD results revealed the formation of Ag2S@AgInS2 core-shell structure. PL spectroscopies revealed a broad NIR emission of Ag2S@AgInS2 core-shells with FWHM of 0.4 eV, large stokes shift of 1.1 eV and QY of 27% in water media.