Synthesis of Alloyed CdxZn1-xS Quantum Dots for Photovoltaic Applications

This article describes the synthesis of CdxZn1-xS quantum dots prepared using the successive ionic layer adsorption and reaction method and incorporated into a photovoltaic device. The CdxZn1-xS quantum dots exhibit good optical and electrical properties. The photovoltaic device has the configuration TiO2/Cd0.75Zn0.25S1/ZnS. A photoconversion efficiency of 3.6% was obtained with this device. This efficiency corresponds to a 16% relative increment compared with a reference sample with the configuration TiO2/Cd1Zn0S1/ZnS. The improvement is associated with an increment in the open-circuit voltage (V-oc) from 0.517 to 0.725 V. The corresponding short-circuit current density (J(sc)) was reduced from 12.15 to 11.66 mA cm(-2). Electrochemical impedance spectroscopy analyses confirm that the behavior of the device was due to a recombination rate reduction obtained as a result of surface passivation between the TiO2 layer and the CdxZnx-1S QDs interface.