Photoinduced Absorption Spectroscopy as a Tool in the Study of Electron Injection and Recombination in CdS quantum Dots Sensitized ZnO Solar Cell

Thin films of ZnO nanoparticulate films have been prepared and modified with CdS quantum dots via chemical bath deposition technique. Photoinduced absorption spectroscopy (PIA), where the excitation is provided by a square-wave modulated (on/off) monochromatic diode light source, is a multipurpose tool in the study of dye-sensitized solar cells. Here, we use PIA as a tool for the study of a quantum-dot modified metal oxide nanostructrued electrode. Oxidized quantum dots can easily be obtained from the spectra of transient species, and their kinetics can be explored using time-resolved techniques. ZnO based CdS photoelectrode has demonstrated best performances in both photoelectrical response and broadening response into visible with a maximum IPCE of 87% at 400 nm. Time constant for electron injection or hole transfer was relatively fast (44 s) and proves at least a well pore filling of ZnO film by ultra fine CdS particles.