Synthesis of Ni:ZnS quantum dots and investigation of their properties

Abstract

ZnS and Ni:ZnS quantum dots (QDs) were prepared by wet-chemical method at room temperature using 1-thioglycerol as a capping agent. The incident photon to- current efficiency measurement was carried out for Ni:ZnS QDs for the first time in this study, showed that Ni:ZnS QDs can be utilized as sensitizers to improve the performance of solar cells. In addition to the photovoltaic properties; structural, optical and magnetic properties of Ni:ZnS QDs have been investigated by X-ray diffraction (XRD), optical absorption, photoluminescence (PL) and physical property measurement system measurements, respectively. The XRD study showed that ZnS and Ni:ZnS QDs have cubic (zinc blende) structure and the particle size of ZnS QDs doped by Ni (2.70 nm) becomes larger than ZnS QDs (2.69 nm). Optical studies (optical absorption and PL) revealed that the absorption and emission of Ni:ZnS QDs (Eg = 3.92 eV, λ = 316 nm) are red-shifted compare to that of ZnS QDs (Eg = 4 eV, λ = 310 nm). The magnetization–magnetic field (M–H) measurement indicated that unlike ZnS QDs, Ni:ZnS QDs shows ferromagnetic behavior at room temperature. Consequently, the results indicate that Ni:ZnS QDs can be suitable material for photovoltaic and spintronic applications.