Enhanced Efficiency of Intermediate-Band Semiconductor Solar Cells Embedded with Quantum Dot Superlattices

TL;DR

This paper develops a multiscale modeling approach combining theoretical calculations, experimental data, and simulations to optimize intermediate-band solar cells with quantum dot superlattices, achieving a maximum efficiency of 13.3%.

Contribution

It introduces a comprehensive framework integrating quantum mechanical band structure, absorption spectra, and device modeling for quantum dot superlattice solar cells, which was not previously available.

Findings

Optimal superlattice constant of 14 nm for maximum efficiency.

Efficiency decreases beyond optimal superlattice size due to reduced generation rate.

Integrated modeling approach reliably predicts device performance.

Abstract

We present a multiscale approach for modeling an intermediate-band solar cell based on a GaAs-GaAlAs quantum dot superlattice of cubic symmetry. Our framework combines high-accuracy theoretical calculations of the superlattice band structure and miniband-related absorption coefficient with experimentally determined interband absorption data. The quantum-mechanically derived absorption spectrum is incorporated into a drift-diffusion transport model in COMSOL Multiphysics, where key processes, including thermal and radiative recombination, are taken into account. This integrated methodology enables realistic modeling of device performance. Our results identify an optimal superlattice constant of 14 nm, yielding a maximum solar cell efficiency of 13.3 percent. Further increase in the superlattice constant enhances the miniband-related absorption peak but reduces the generation rate in the n-type region, resulting in a net efficiency decrease. The proposed approach, integrating theoretical, experimental, and computational components, provides a reliable framework for assessing solar cells based on quantum dot superlattices.