Influence of chemical treatments on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films

Effects of Ti(iso-C3H7O)4 and TiCl4 treatments on the photoinduced charge carrier kinetics of nanocrystalline porous TiO2 films were studied by time-resolved microwave conductivity measurements. Both treatments greatly influence the transient microwave photoconductivity decay behaviors by increasing the photogenerated charge carrier concentration and diminishing the charge carrier recombination via suppressing the hole-trapping defects. This leads to improve the I–V behaviors of nanocrystalline porous TiO2 films effectively. The results are discussed in terms of surface modification of anatase nanocrystallites which grow on the film surface by hydrolysis of Ti(iso-C3H7O)4 and TiCl4 during the treatments.