Evaluation of Reaction Parameters Dependent Optical Properties and Its Photovoltaics Performances of CdTe QDs

High quality thiol capped cadmium telluride quantum dots were prepared in aqueous phase by the optimization of reaction parameters and their photovoltaics performances were studied through the fabrication of quantum dots sensitized solar cells. Mercaptosuccinic acid capped cadmium telluride quantum dots were prepared under different rection conditions (at acidic and basic solutions, different precursors ratios, under different reaction temperatures and are various refluxing times) and their optical absorptionand emission properties were studied. Based on these observations, the reaction parameters were optimized and high quality mercaptosuccinic acid capped cadmium telluride quantum dots were prepared at the optimized reaction conditions. Crystalline structure of the prepared cadmium telluride quantum dots was studied by X-ray diffraction analysis, which confirms the cubic zinc blende structure. Size dependent optical properties of mercaptosuccinic acid capped cadmium telluride quantum dots were revealed by UV-Vis absorption and fluorescence emission studies. The formation of cadmium telluride quantum dots with the thiol capping layer over the quantum dots was studied by the X-ray photoelectron spectroscopy and Fourier Transform Infra Red spectroscopy analysis. Cadmium telluride quantum dots sensitized solar cells were fabricated by using polysulfide electrolytes with TiO2 as the photoanode. The photovoltaic performance of cadmium telluride quantum dots sensitized photoelectrodes was studied by the J-V characteristic curves under the illumination of light with 1 Sun intensity. Mercaptosuccinic acid capped cadmium telluride quantum dots prepared at optimized reaction conditions showed an enhanced solar cell efficiency of 0.87% at 3 h of absorption time.