Photo-induced refraction of nanoparticulate organic-inorganic TiO₂-pHEMA hybrids

摘要

We report on photoinduced modifications of the refractive index of nanoparticulate TiO2-pHEMA organic-inorganic hybrids. The samples with titania concentration ranging from 0.88·1020 to 17.6·1020 cm−3 were irradiated and analyzed with UV light at 375 nm. A reduction of the refractive index is observed in all samples. Although the photoinduced refraction was stronger in samples with higher titania concentration, its normalized value per Ti3+ center a0 = −2.4·10−23 cm3 remained constant. The change of refractive index correlates with the material photochromic response due to the accumulation of polaronic Ti3+ centers in the material.