Morphology modification of TiO2 film by adding ammonium nitrate in precursor sol

► We prepared pore and particle modified TiO2 films by adding NH4NO3 into TiO2 sol. ► Introduction of NH4NO3 results in phase separation during drying process. ► Formation of pore or particle depends on the condensation rate of water vapor. ► NH4NO3 also acts as N source to form N-doped TiO2 film.