LAUSR

For colloidally stable nanoparticle dispersions, it is imperative that some sort of interparticle repulsion is introduced to balance or overcome the ever-present van der Waals forces of attraction. In the present work, we have demonstrated that an efficient stabilization of a TiO2 nanoparticle dispersion depends upon the pH and zeta potential which are influenced by the route of synthesis (aqueous or ethanol based) and by the addition of suitable polymeric dispersants. In this work, both pH and zeta potential of the TiO2 nanoparticles have been accredited as a good index of the magnitude of the interaction between colloidal particles and their measurements are used to assess the stability of TiO2 and polymer/TiO2 composite colloidal systems synthesized via different routes. The concept of steric and electrostatic stabilization of colloids for both TiO2 (aqueous) and TiO2 (ethanol) systems and its corresponding polymer nanocomposites has been explained appropriately by means of a pictorial model. The efficient charge transfer across the polymer-TiO2(aqueous) interface as inferred from photoluminescence quenching measurements meets the desired criteria for the selection of TiO2(aqueous) materials for hybrid organic photovoltaic devices.