Nanocryst. TiO2 films, surface modified with Al3+, were manufd. by depositing a TiO2 suspension contg. small amts. of Al nitrate or Al chloride onto conducting glass substrates, followed by drying, compression, and finally heating to 530°. Electrodes prepd. with TiO2 nanoparticles coated with <0.3% Al2O3 with respect to TiO2 improved the efficiency of the dye-sensitized solar cell. This amt. corresponds to less than a monolayer of Al2O3. Thus, the Al ions terminate the TiO2 surface rather than forming a distinct Al2O3 layer. The Al-ion surface treatment affects the solar cell in different ways: the potential of the conduction band is shifted, the electron lifetime is increased, and the electron transport is slower when Al ions are present between interconnected TiO2 particles.