Growth behavior of CdS nanoparticles embedded in polymer and sol-gel silica matrices: Relationship with surface-state related luminescence

Chemical techniques were employed to synthesize US nanoparticles embedded in polymer (PEG 300) and sol-gel silica matrices. Systematic growth of particles (radius 3-9 nm) was obtained by adjusting post-deposition annealing temperature and time to examine the dependence of surface-state-related luminescence on particle size. Photoluminescence (PL) peak energy showed a linear dependence with a gentle slope in the weak confinement region and a steep slope in the strong confinement region, the divergence being observed near the excitonic Bohr radius for CdS. The empirical relation proposed for the weak confinement region could be used for estimating chemically prepared US nanoparticle size with a high degree of reliability from PL peak energy.