Effect of neodymium doping on the structure and optical properties of mesoporous TiO₂ thin films

Mesoporous TiO2 thin films doped with varying amounts of neodymium have been synthesized via a copolymer templated sol-gel route. The films exhibited highly ordered mesostructures at low levels of neodymium doping, and disordered mesostructures at high dopant levels (i.e., Nd/Ti ≥ 30 mol%). As the neodymium concentration increased, the films showed degradation in the nanocrystallinity, indicating that the presence of neodymium dopants adversely affects the growth of titania nanocrystallites. Moreover, the addition of neodymium resulted in a marked blue shift of the absorption edge and an evident increase in bandgap energy for the mesoporous TiO2 thin films.