Photoconductivity studies on surface modified TiO2 nanoparticles

Surface modified nanoparticles of P25 Evonic Degussa TiO2 with silane coupling agent 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTMS) were prepared at low temperature conditions. The impact of the AAPTMS modifier on the composition and the photoconductivity behavior of the TiO(2 )nanoparticles were investigated. Thus the initial and the modified TiO2 nanoparticles were characterized using the XPS technique and their transient photoconductivity was measured. In order to investigate the influence of the environment, measurements were conducted in vacuum and in air. The effect of temperature and light intensity was also examined. It was found that 0.9 is the optimum choice of the molar ratio AAPTMS/P25 for achieving the higher sigma(p) values. Moreover, in air, a significant decrease of four or five orders of magnitude occurs in photoconductivity, attributed to electron scavengers O-2(-).