# First-principles prediction into robust high-performance photovoltaic double perovskites A$_{2}$SiI$_{6}$ (A = K, Rb, Cs)

## TL;DR

This study uses first-principles calculations to predict a new family of stable, non-toxic silicon-based double perovskites with suitable band gaps and excellent optical properties for high-performance photovoltaic applications.

## Contribution

It introduces a novel class of silicon-based double perovskites, expanding the materials options for stable, efficient, and non-toxic solar cell absorbers.

## Key findings

- Suitable band gaps of 0.84-1.15 eV
- Good stability at high temperature
- Wide photon absorption in visible range

## Abstract

Despite the exceeding 23\% photovoltaic efficiency achieved in organic-inorganic hybrid perovskite solar cells obtaining, the stable materials with desirable band gap are rare and are highly desired. With the aid of first-principles calculations, we predict a new promising family of nontoxic inorganic double perovskites (DPs), namely, silicon (Si)-based halides A$_{2}$SiI$_{6}$ (A = K, Rb, Cs; X = Cl, Br, I). This family containing the earth-abundant Si could be applied for perovskite solar cells (PSCs). Particularly A$_{2}$SiI$_{6}$ exhibits superb physical traits, including suitable band gaps of 0.84-1.15 eV, dispersive lower conduction bands, small carrier effective masses, wide photon absorption in the visible range. Importantly, the good stability at high temperature renders them as promising optical absorbers for solar cells.