**5.2 0-dimensional (0D) titanium dioxide (TiO2) Nanosphere**

Particles which are more or less spherical in shape like fullerenes, quantum dots, nano-onions, nanoparticles, etc. are considered as 0D. These 0D nanomaterials are sized at nanoscale level in all three dimensions and must be amorphours or crystalline; single or polycrystalline; and composed of single- or multichemical element. Within 0D materials, all electrons are fully confined and their length equals the width. Due to confinement of both electrons and holes, the lowest energy optical transition from the valence to conduction band will increase in energy, effectively increasing the band gap. A 0D TiO2 nanosphere (**NS**) film is noticed as a effective
