  We have used simple chemical bath deposition technique to grow nearly
monodispersive CdS nanocrystals in PVP matrix. Systematic study of variation of
growth parameters has revealed that optimized growth of CdS nanocrystals in PVP
matrix depends on relative concentration of Cd acetate/Thiourea to polyvinyl
pyrrolidone in the bath. It is also observed that higher concentration (1M) of
Cd acetate/Thiourea gives rise to smaller NCs compared to lower concentration
(0.5M), however density of particles is large in thin film grown using 1M
concentration. Scanning electron microscopic studies show that it is a
nanoparticulate film of spheres of size around 100-200nm. Further, absorption,
energy dispersive spectroscopy and transmission electron microscopic
investigations reveal that nearly monodispersive CdS nanocrystals are embedded
in 100-200 nm PVP spheres for the range 0.5 M, 1M Cd acetate/Thiourea
concentration (figure 1). The effect of varying PVP, Cd acetate/Thiourea
concentration, sequence and addition of ingredients and heating/cooling cycles
have been studied and results are corroborated with existing theory.
