Ultrasound effect: Preparation of PbS/TiO2 heterostructure nanotube arrays through successive ionic layer adsorption and the reaction method

PbS-modified TiO2 heterostructure nanotube arrays (NAs) were synthesised by successive ionic layer adsorption and the reaction method. Ultrasound (PbS(u)/TiO2 NAs) has an important function in the formation of PbS nanoparticles. Compared with non-ultrasound PbS/TiO2 NM, PbS(u)/TiO2 NAs have small PbS nanoparticles uniformly distributed on both the outside and inside rather than the top surface of TiO2 NM. The average size of the PbS nanoparticles in PbS(u)/TiO2 NAs ranges from 10 to 15 nm. PbS/TiO2 NM and PbS(u)/TiO2 NAs both exhibit high absorption in the 300-1000 nm region. Moreover, a stronger separate efficiency of photogenerated charge carriers is found in PbS(u)/TiO2 NAs than that in PbS/TiO2 NM. (C) 2013 Elsevier B.V. All rights reserved.