Characterisation of samarium and nitrogen co-doped TiO2 films prepared by chemical spray pyrolysisOja Acik, Ilona; Kiisk, Valter; Krunks, Malle; Sildos, Ilmo; Junolainen, Agne; Danilson, Mati; Mere, Arvo; Mikli, ValdekApplied surface science2012 / p. 735-741 : ill