Structural and Optical Properties of Macroporous Ag@TiO 2 Thin Films Prepared by a Facile One-Step Sol–gel Method

A principle of obtaining macroporous Ag@TiO2 thin films by a template-free method in the frame work of sol–gel is developed. The macroporous structure is constructed by photo polymerization induced phase separation (PIPS) method, and the reduction of Ag+ to Ag0 is induced by ultraviolet irradiation at the same time. The achieved macroporous Ag@TiO2 films are well interconnected and crack free with an average pore size in the range 350–440 nm. Increasing Ag concentration results in the enhancement of extinction coefficient and reduction of refractive index, which are found to be consistent with absorbance and transmittance observations. In addition, Ag concentration causes red shift in absorbance which in turn decreases the band gap energy. These results may add important insight into developing high-performance materials for visible light activities.