Perspective of Electrochromic Double Layer Towards Enrichment of Electrochromism: A Review

Electrochromism is the exhibition of reversible optical property changes by certain materials upon administration of voltage across it. Tungsten oxide (WO3) finds a diverse range of applications because of its exceptional electrochromism. Amidst all applications, an electrochromic device (ECD) can be considered the most prominent application due to energy saving perspective. Although, WO3 itself has been noticed as an efficient electrochromic layer for EDCs; however, there exists a lot of space and ideas to enhance the electrochromism and hence the efficiency of an ECD. Recently, scientists are paying close attention to hybrid or composite films such as TiO2/WO3 and TiO2/V2O5. Such hybrid films are known as electrochromic double layer (ECDL). This review article strives to deepen our understanding of ECDL and assess their feasibility in the enrichment of electrochromism in ECDs by replacing a single electrochromic layer with an ECDL toward an energy-saving regime. Graphical Abstract: (Figure presented.). © The Author(s) under exclusive licence to Sociedade Brasileira de Física 2024.