# Electrochromic Efficiency in AxB(1−x)Oy-Type Mixed Metal Oxide Alloys

## TL;DR

This review explores mixed metal oxides as electrochromic materials for smart windows, highlighting their potential for energy-efficient applications.

## Contribution

The study reviews multicomponent metal oxides, identifying promising mixtures like WO3–MoO3 with high coloration efficiency.

## Key findings

- Mixed metal oxides show improved electrochromic properties compared to pure oxides.
- Magnetron-sputtered WO3(40%)–MoO3(60%) has a coloration efficiency of 200–300 cm2/C.
- Mixed oxides have potential for commercialization in electrochromic devices.

## Abstract

Electrochromic materials have a wide range of energy-effective applications, such as in mirrors, smart windows, automobile sunroofs, and display devices. The electrochromic behavior of mixed metal oxides is focused on in this review. Extra heat absorbed by buildings is one of the major problems in our modern era, so electrochromic films have been used as components of smart windows to reduce heat absorption through glass windows. Transition metal (W, V, Ti, Mo, and Ni) oxides are considered popular electrochromic materials for this purpose. Smart windows consist of electrochromic material layers (such as metal oxide layers) and solid electrolytes sandwiched between transparent conductive layers. Few publications have studied the use of mixtures of different metal oxides as electrochromic materials. This study focuses on the results of investigations of such multicomponent materials, such as the effects on the electrochromic properties of mixed metal oxides and how they contrast with pure metal oxides. Reviewing these papers, we found WO3- and MoO3-based mixtures to be the most promising, especially the magnetron-sputtered, amorphous WO3(40%)–MoO3(60%) composition, which had 200–300 cm2/C coloration efficiency. The mixed oxide materials reported in this review have room for development (and even commercialization) in the oxide-based electrochromic device market.