NANODEV Research Group


Photochromism

Photochromism is defined as a light-induced reversible change of color. General applications of photochromism can be divided into two categories: (i) those directly related to the change in absorption spectra such as; optical information storage, variable transmission optical materials, and (ii) those related to other physical or chemical property changes such as; refractive index, dielectric constant etc. The most famous applications are smart windows and sunglasses. Up to now, photochromic properties of organic materials such as; spirooxazine, chromene derivatives, and azobenzene have been most systematically examined. However, the number of inorganic materials known to display photochromism is limited. The most explored thin-film inorganic photochromic materials are the transition metal oxides WO3, NiO, and MoO3 , which have also been investigated for application in electrochromic devices  that show a reversible color change when a small DC voltage is applied. Photochromic behavior of silver nanoparticle loaded Engelhard titanosilicate (ETS-10) can be considered due to 1-D quantum-confined form of titania chains (i.e., TiO32-) that run in the crystal a and b directions and exchangeable extra framework charge-balancing cations (i.e., Na+ and K+) in the as-synthesized materials as indicated by the ETS-10 stoichiometry (Na,K)2TiSi5O13. In our group, the partially reversible photochromic behavior of silver(0) nanoparticle incorporated titanosilicate ETS-10 films was achieved for the first time.