Comparative studies of optoelectrical properties of prominent PV materials: Halide Perovskite, CdTe, and GaAs

TL;DR

This study compares the optoelectrical properties of halide perovskite, CdTe, and GaAs PV materials, revealing that perovskites have lower recombination rates and higher efficiencies due to structural disorder and surface effects.

Contribution

It provides a comprehensive comparative analysis of PV materials using novel imaging and modeling techniques, highlighting the unique advantages of perovskites.

Findings

Perovskites exhibit higher PL efficiency than CdTe and GaAs.

Structural disorder in perovskites suppresses nonradiative recombination.

Lower surface recombination contributes to perovskite's high PV efficiency.

Abstract

We compare three representative high performance PV materials: halide perovskite MAPbI3, CdTe, and GaAs, in terms of photoluminescence (PL) efficiency, PL lineshape, carrier diffusion, and surface recombination, over multiple orders of photo-excitation density. An analytic model is used to describe the excitation density dependence of PL intensity and extract the internal PL efficiency and multiple pertinent recombination parameters. A PL imaging technique is used to obtain carrier diffusion length without using a PL quencher, thus, free of unintended influence beyond pure diffusion. Our results show that perovskite samples tend to exhibit lower Shockley-Read-Hall (SRH) recombination rate in both bulk and surface, thus higher PL efficiency than the inorganic counterparts, particularly under low excitation density, even with no or preliminary surface passivation. PL lineshape and diffusion analysis indicate that there is considerable structural disordering in the perovskite materials, and thus photo-generated carriers are not in global thermal equilibrium, which in turn suppresses the nonradiative recombination. This study suggests that relatively low point-defect density, less detrimental surface recombination, and moderate structural disordering contribute to the high PV efficiency in the perovskite. This comparative photovoltaics study provides more insights into the fundamental material science and the search for optimal device designs by learning from different technologies.