Effect of doping, photodoping and bandgap variation on the performance of perovskite solar cells

TL;DR

This paper uses numerical simulations to explore how doping, photodoping, and bandgap changes affect the performance of perovskite solar cells, revealing optimal doping levels for efficiency.

Contribution

It provides new insights into the effects of doping on photoluminescence and photovoltaic performance in perovskite solar cells through detailed numerical analysis.

Findings

Doping enhances photoluminescence quantum yield by increasing radiative recombination.

High doping densities can reduce diffusion length, impairing carrier collection.

Optimal doping density improves photovoltaic efficiency depending on material properties.

Abstract

Most traditional semiconductor materials are based on the control of doping densities to create junctions and thereby functional and efficient electronic and optoelectronic devices. The technology development for halide perovskites had initially only rarely made use of the concept of electronic doping of the perovskite layer and instead employed a variety of different contact materials to create functionality. Only recently, intentional, or unintentional doping of the perovskite layer is more frequently invoked as an important factor explaining differences in photovoltaic or optoelectronic performance in certain devices. Here we use numerical simulations to study the influence of doping and photodoping on photoluminescence quantum yield as well as other device relevant metrics. We find that doping can improve the photoluminescence quantum yield by making radiative recombination faster. This effect can benefit or harm photovoltaic performance given that the improvement of photoluminescence quantum efficiency and open-circuit voltage is accompanied by a reduction of the diffusion length. This reduction will eventually lead to inefficient carrier collection at high doping densities. The photovoltaic performance might improve at an optimum doping density which depends on a range of factors such as the mobilities of the different layers and the ratio of the capture cross sections for electrons and holes.