Charge recombination suppressed CdSeS/CdSe/ZnS QDSSC design

Abstract

The interest in quantum dot sensitized solar cells (QDSSC), which has theoretically proved to have up to 44% energy conversion efficiency in recent years, is growing rapidly. Although it has theoretically high efficiency value, PCE obtained in studies with QDSSCs is far from these values. This situation shows that there are many difficulties to be solved in QDSSC technology. One of the main challenges in QDSSC technology is irradiated load recombination occurring in QDSSC. For this reason, in this study, it is about using CdSeS QDs as an alternative to the most used CdS QDs in the literature in order to suppress the load recombination between TiO2 surface and electrolyte and QD surfaces. In the study, while CdS and CdSeS QDs were coated on the TiO2 surface with SILAR method, the previously synthesized CdSe QD was coated with chemical deep deposition method. Surfaces were last treated with ZnS QDs. An optimization study was carried out to determine the ideal number of CdSeS coatings for QDSSCs. As a result, the Jsc and Voc values for TiO2/CdSeS4/CdSe/ZnS QDSSCs were 8.799 mA/cm2 and 0.795 V, respectively, while the PCE value increased to 4.452%.