Facile synthesis of nano-sized zinc-rich ZnCdS ternary alloy and UV-irradiation curing of photoluminescence emission characteristics

Zn-rich ZnCdS nanoparticles (NPs) are successfully synthesized by a facile chemical co-precipitation technique at room temperature. The crystal structure homogeneity of the as-synthesized ternary alloy is examined by the x-ray diffraction pattern and the micro-Raman spectroscopy. The average crystalline domain size is about 4 nm indicating the spatial particle confinement of ternary ZnCdS NPs. The optical bandgap (E-g) of the as-synthesized ZnCdS NPs is 3.95 eV that is higher than the corresponding ternary bulk alloy due to the improvement in the quantum size effect. The effect of UV irradiation on the optical band gap of ZnCdS NPs is investigated at different exposure times. A strong decrease in E-g is observed with increasing exposure time up to 60 min followed by E-g saturation at higher UV exposure times. The as-synthesized ZnCdS nanopowder exhibits a wide emission spectrum extending from UV to visible spectral region, which originating from various intrinsic structural defects. The aging of the as-synthesized ZnCdS nanopowder results in emission intensity quenching without changing peak positions. The emission intensity is recovered by the direct exposure to UV irradiation. This indicates the ability of UV irradiation to cure the emission characteristics of small NPs. This would provide more durability about the emission characteristics of the ZnCdS NPs-based fluorescence sensor.

Automated summary

Zn-rich ZnCdS nanoparticles are successfully synthesized using a chemical co-precipitation technique, exhibiting homogeneous crystal structure and an average crystalline domain size of about 4 nm. The optical bandgap of the nanoparticles is found to be 3.95 eV, higher than the corresponding bulk alloy due to the quantum size effect. UV irradiation can impact the optical band gap, with a decrease in E-g observed up to 60 min of exposure time followed by saturation at higher UV exposure times. The emission spectrum of the ZnCdS nanopowder extends from UV to visible spectral region and can be recovered by direct exposure to UV irradiation, indicating the potential for durability in fluorescence sensor applications.