On the synergistic coupling properties of composite CdS/TiO2 nanoparticle arrays confined in nanopatterned hybrid thin films

Abstract

Two-dimensional (2D) arrays of hybrid CdS/TiO2 composite nanodots were fabricated on solid substrates using amphiphilic poly(styrene-block-ethylene oxide) diblock copolymer (PS-b-PEO) micelles as templates loaded with CdS nanoparticles (NPs) and TiO2 sol-gel precursors. The inorganic precursors were selectively incorporated into PEO domains of PS-b-PEO due to the specific interactions. The addition of CdS quantum dots (QDs) into thin films of the PS-b-PEO/TiO2 sol-gel mixture led to the morphological changes from mixed wire/hexagonal dot to well-defined, quasi-hexagonal dot arrays. The PS-b-PEO/TiO2/CdS system showed an enhanced absorption along with red shift behavior in the UV-visible spectral range compared with the PS-b-PEO/TiO2 films. Photoluminescence (PL) studies showed a quenching of CdS emission in the presence of TiO2. An enhanced photocatalytic degradation of methylene blue (MB) was observed in the hybrid PS-b-PEO/TiO2/CdS thin film.