Conversion efficiency of strained core/shell quantum dot solar cell: Converting from type-I to type-II structures

Abstract

In this study, we further modify the modified detailed balance model given by Sahin to make it applicable to more materials. We use the further modified model to study the conversion efficiency (CE) of a core/shell quantum-dot (QD) solar cell, which can convert from a type-I to a type-II structure as a function of its material composition. In addition, a size-dependent strain effect caused by the lattice mismatch is also considered because the original detailed balance model depends strongly on the bandgap of the material. The results show that the modified model used herein is valid for materials with a wide range of variable oscillator strengths and that the CE obtained with this model depends not only on the energy gap but also on the QD structure, so the results are very different for type-I and type-II QD structures. In addition, the results show that the size-dependent strain effect strongly influences the band structure of the materials, so the CEs with and without the strain effect are very different, especially for a type-II QD solar cell.