Issue 5, 2020

Upper limit to the photovoltaic efficiency of imperfect crystals from first principles

Abstract

The Shockley–Queisser (SQ) limit provides a convenient metric for predicting light-to-electricity conversion efficiency of a solar cell based on the band gap of the light-absorbing layer. In reality, few materials approach this radiative limit. We develop a formalism and computational method to predict the maximum photovoltaic efficiency of imperfect crystals from first principles. The trap-limited conversion efficiency includes equilibrium populations of native defects, their carrier-capture coefficients, and the associated recombination rates. When applied to kesterite solar cells, we reveal an intrinsic limit of 20% for Cu2ZnSnSe4, which falls far below the SQ limit of 32%. The effects of atomic substitution and extrinsic doping are studied, leading to pathways for an enhanced efficiency of 31%. This approach can be applied to support targeted-materials selection for future solar-energy technologies.

Graphical abstract: Upper limit to the photovoltaic efficiency of imperfect crystals from first principles

Supplementary files

Article information

Article type
Paper
Submitted
29 jan 2020
Accepted
09 mar 2020
First published
09 mar 2020
This article is Open Access
Creative Commons BY license

Energy Environ. Sci., 2020,13, 1481-1491

Upper limit to the photovoltaic efficiency of imperfect crystals from first principles

S. Kim, J. A. Márquez, T. Unold and A. Walsh, Energy Environ. Sci., 2020, 13, 1481 DOI: 10.1039/D0EE00291G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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