Comparative Analysis of Excitonic and Biexcitonic Effects on the Power Conversion Efficiency of a CdSe/CdTe/ZnTe Quantum Dot Solar Cell

Abstract

In this study, the power conversion efficiency (PCE) of a CdSe/CdTe/ZnTe quantum dot solar cell (QDSC) is investigated considering the influence of internal parameters such as CdSe core radius and CdTe and ZnTe shell thickness along with external parameters such as temperature and hydrostatic pressure. A comparative analysis is performed using both the original detailed balance model (ODBM) and the modified detailed balance model (MDBM). The main focus of the research is to investigate the effects of excitonic and biexcitonic effective gap energies, as well as the biexciton bound state, on the PCE in the presence of multiple exciton generation (MEG). Calculations using both ODBM and MDBM indicate that the distinct excitonic and biexcitonic effective bandgap energies, resulting from strong confinement effects in quantum dot (QD) structures, significantly affect the PCE in the presence of MEG. In addition, MDBM calculations considering the biexciton bound state show that this bound state critically affects the PCE. The discrepancy between the theoretically predicted maximum PCE and the considerably lower PCE observed in practical applications of QDSCs is also examined, along with the potential reasons for this phenomenon.