Crystal shape and size of CdTe colloidal quantum dots controlled by silver doping for enhanced quantum dots sensitized solar cells performance

Pristine and silver (Ag) doped (0-5 at. %) CdTe QDs were synthesized by the colloidal process in an aqueous medium. The red shift in absorption and emission peak positions was observed with respect to Ag doping con-centrations due to a change in composition (Cd1-xAgxTe). During the synthesis, the concentrations of silver doping played a significant role in controlling the shape and size of CdTe QDs. XRD studies indicate the crystal undergoes a series of shapes from octahedron to truncated octahedron followed by truncated cube to cube in CdTe QDs with respect to silver doping concentrations. The morphologies and elemental compositions of CdTe and Cd1-xAgxTe QDs were studied by HRTEM and EDX analysis. The photovoltaic efficiency of fabricated devices using CdTe QDs was increased from 0.85% to 1.66% with increasing Ag concentrations. The JSC of the J-V measurement and the integrated JSC of IPCE follow the same trend. Thus, silver doping manipulates the crystal shape and size of CdTe QDs and is quite efficient for visible light utilization, separation of charges, and enhances the solar cell efficiency.