The photovoltaic performance of alloyed CdTexS1−x quantum dots sensitized solar cells

The photovoltaic performance of alloyed CdTexS1−x quantum dots (QDs) sensitized solar cells (QDSSCs) as a function of tuning the band gap of alloyed CdTexS1−x QDs is studied. The tuning of band gap was carried out through controlling the molar ratio (x) of QDs. Presynthesized alloyed CdTexS1−x QDs of different x values (0, 0.2, 0.4, 0.6, 0.8, and 1) were deposited by direct adsorption (DA) technique onto a layer of TiO2 nanoparticles (NPs) to serve as sensitizers for the solar cells. The characteristic parameters of the assembled QDSSCs were measured under AM 1.5 sun illumination, and show that CdTexS1−x QDs has better photovoltaic performance than pure CdTe QDs or CdS QDs. The maximum values of Jsc (1.54 mA/cm2) and η (0.31%) were obtained for x=0.6. However, The open circuit voltages (Voc) approximately constant (0.46±0.02 V) for all alloyed CdTexS1−x QDSSCs. It is only dictated by the conduction band (CB) level of TiO2 nanoparticles (NPs) and the valance band (VB) of the electrolyte.