Lead Free Alloyed Double Perovskites: An Emerging Class of Materials from Many-Body Perturbation Theory

TL;DR

This study uses many-body perturbation theory to analyze the optoelectronic and transport properties of lead-free alloyed double perovskites, revealing phonon scattering effects and mobility enhancements relevant for photovoltaic applications.

Contribution

It provides a detailed theoretical analysis of carrier-lattice interactions and optoelectronic properties of alloyed Cs₂AgInCl₆ double perovskites using advanced computational methods.

Findings

Phonon scattering limits charge-carrier mobilities.

Dominant carrier-phonon scattering via Frohlich mechanism near room temperature.

Alloying increases hole and electron mobilities.

Abstract

The discovery of lead free all-inorganic alloyed double perovskites have revolutionized photovoltaic research, showing promising light emitting efficiency and its tunability. However, detailed studies regarding optical, exciton, polaron and transport properties remain unexplored. Here, we report a theoretical study on the variation of carrier-lattice interaction and optoelectronic properties of pristine as well as alloyed Cs$_2$AgInCl$_6$ double perovskites. We have employed many-body perturbation theory (G$_0$W$_0$@HSE06) and density functional perturbation theory (DFPT) to compute exciton binding energy (E$_\textrm{B}$) and exciton lifetime of different alloyed double perovskites. We find that phonon scattering limits charge-carrier mobilities and thus, plays an important role in the development of high-efficiency perovskite photovoltaics. In view of this, dominant carrier-phonon scattering is observed via Fr\"{o}hlich mechanism near room temperature. Moreover, we observe a noticeable increase in hole and electron mobilities on alloying. We believe that our results will be helpful to gain a better understanding of the optoelectronic properties and lattice dynamics of these double perovskites.