Numerical Study of Thin-Film Quantum-Dot Solar Cells Combining Selective Doping and Light-Trapping Approaches

摘要

We investigate GaAs-based quantum dot (QD) solar cells that exploit selective QD doping to mitigate open circuit voltage loss and light trapping enhancement of QD harvesting to increase the QD contribution to short-circuit current. Devices are simulated using an ad hoc developed physics-based model that accurately describes QD carrier dynamics within a semi-classical semiconductor transport model. The study of a realistic device structure under different hypotheses of crystal quality allows the impact of doping on device performance to be assessed both in radiative limited and non-radiative limited cases. We show that large open circuit voltage recovery is attainable in both cases due to the simultaneous suppression of radiative recombination through QD confined states and of non-radiative recombination in the barrier material, thus confirming the use of selective doping as a good strategy for optimizing QDSC design. Then, we study thin-film QDSCs that combine selective doping with light trapping approaches. The efficiency enhancement allows the QD cell to overcome the bulk reference one even under unconcentrated light.