Alloyed CdTe 0.6 S 0.4 Quantum Dots Sensitized TiO 2 Electrodes for Photovoltaic Applications

The photovoltaic performance of alloyed CdTe0.6S0.4 quantum dot sensitized solar cells (QDSSCs) is investigated. Fluorine doped Tin Oxide (FTO) substrates were coated with 20 nm-diameter TiO2 nanoparticles (NPs). Presynthesized colloidal solution of alloyed CdTe0.6S0.4 quantum dots (QDs) of 4.2 nm was deposited onto TiO2 NPs substrates using direct adsorption (DA) technique, by dipping for different times at ambient conditions. The FTO counter electrodes were coated with platinum, while the electrolyte containing I − /I −3 redox species was sandwiched between the two electrodes. Compared to pure CdTe QDs and CdS QDs, CdTe0.6S0.4 QDs showed better photovoltaic performance. The J-V characteristic curves of the assembled QDSSCs were measured at AM 1.5 simulated sunlight. The short current density (Jsc) and efficiency (η) increase with dipping time. At 24 h dipping time, the open-circuit photovoltage Voc, Jsc, fill factor (FF), and η were 0.46 volts, 1.54 mA/cm 2 , 0.43% and 0.31%, respectively.