Photochromic Applicationbs of Titanium Dioxide in Various Forms
5th International Conference on Applied Surface Science: Book of Abstracts 2022
Raivis Eglītis, Andris Šutka

Photochromic materials as the name implies, possess the ability to change their light absorbance when exposed to light. This allows it to be used for passive light modulation. Titanium dioxide (TiO2) undergoes this process when exposed to UVA light under anaerobic conditions when a hole scavenger is present. Since a hole scavenger is necessary, the surrounding medium of the TiO2 will influence the resulting photochromic effect. The highest photochromic capability can be achieved when the TiO2 / hole scavenger interfacial area is the highest, for example, nanoparticles dispersed in a colloid. However, for practical applications, particles in a colloidal form pose many challenges, mainly leakage and solvent evaporation. Another possibility is thin films or polymer composites. However, thin films possess a comparatively low interfacial area, resulting in a low photochromic performance while TiO2/polymer composites have so far also shown poor performance when compared to colloids. A golden middle‑point between these two could be nanoparticle dispersions in a gel form. These can retain any hole scavengers while also allowing the TiO2 nanoparticles to be disperse enough, for efficient hole scavenging. However, most reported gels are opaque, which also undermines their usability in applications were high optical transparency is mandatory. By conducting polymerization under certain conditions, we’ve prepared transparent TiO2 gels, that also possess the ability to photodarken under UVA light and slow recovery when the UVA light is turned off. The properties and compositional dependencies of the photochromic properties have been studied and are reported.


Keywords
Titāna dioksīds; Fotohromisms;

Eglītis, R., Šutka, A. Photochromic Applicationbs of Titanium Dioxide in Various Forms. In: 5th International Conference on Applied Surface Science: Book of Abstracts, Spain, Palma de Mallorca, 25-28 April, 2022. ASV: 2022, pp.P2.52-P2.52.

Publication language
English (en)
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