Synthesis, characterizations and photovoltaic properties of Cr-doped CdS QDs

Abstract

The synthesis and characterizations of CdS and Cr (3%)-doped CdS QDs have been reported, prepared by the wet-chemical method at room temperature using the using 1-thioglycerol as a capping agent. Their structural, optical and magnetic properties have been studied. The structural properties showed that the CdS and Cr (3%)-doped CdS QDs have cubic (zinc blende) structure and the particle size of Cr (3%)-doped CdS QDs (2.29 nm) becomes smaller than CdS QDs (2.31 nm). Optical absorption spectra revealed that the absorbance of Cr (3%)-doped CdS QDs is blue shifted compare to CdS QDs. The blue shift in the absorption edge is due to the quantum confinement of the excitons present in the sample, causing more discrete energy spectrum of the individual QDs. It was observed that the emission spectrum of Cr (3%)-doped CdS QDs is red-shifted. This situation may be ascribed to the creation of new radiation centers by Cr doping in CdS matrix. The M–H measurements indicated that unlike CdS QDs, Cr (3%)-doped CdS QDs indicates the ferromagnetic behavior at room temperature. The room temperature ferromagnetism observed in Cr (3%)-doped CdS QDs could be due to mixing of Cr in Cd. Moreover, the effect of Cr dopant on the performance of CdS QDSSCs has been investigated. The IPCE and J-V measurements were carried out for Cr (3%)-doped CdS QDs for the first time in this study revealed that Cr (3%)-doped CdS QDs can be utilized as sensitizers to improve the performance of solar cells.