# Mechanochemical Formation Mechanism of Alloyed AgBi-Elpasolites

## TL;DR

This paper explains how alloyed AgBi-elpasolite materials form during mechanochemical ball milling, offering insights into their crystallization process.

## Contribution

The study reveals distinct formation pathways for alloyed AgBi-elpasolites using in situ synchrotron X-ray diffraction.

## Key findings

- Reaction intermediates for Cs2AgBiBr6 were identified during mechanochemical synthesis.
- Alloying with In3+ or Fe3+ involves an additional cation-exchange step compared to Sb3+.
- The findings provide a framework for engineering complex material compositions.

## Abstract

Mechanochemical ball
mill synthesis is an emerging method
for producing
complex materials, including alloyed halide elpasolite semiconductors.
This solvent-free method offers precise control over chemical composition,
enabling fine-tuning of the optical and mechanical properties. However,
the formation mechanism of alloyed elpasolites remains unclear. In
this work, we elucidate the crystallization kinetics of mechanochemical
formation of Cs2AgBi0.5M0.5Br6 [M = Sb3+, In3+, or Fe3+] using in situ synchrotron X-ray diffraction experiments.
We identify the reaction intermediates for the parent composition
Cs2AgBiBr6, and we find that −Bi0.5Sb0.5– forms via a similar reaction pathway.
Alloying with In3+ or Fe3+, on the other hand,
occurs via an additional cation-exchange step. These insights into
the mechanochemical formation mechanisms of alloyed AgBi-elpasolites
provide guidelines toward rational compositional engineering of complex
materials.