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Zinc Sulphide (ZnS) nanoparticles doped with different concentrations of Mn 2+ (0%, 2%, 4%, 6%, 8%, 10%) have been synthesized by chemical co-precipitation method using polyvinyl alcohol (PVA) as a capping agent to control the particle growth. The structural characterizations of as synthesized nanoparticles are determined by X-ray diffraction (XRD) which showed cubic zinc blende structures with average crystallite sizes of the range 2.3 nm-2.1 nm. There is no phase transformation due to Mn 2+ doping and this characteristic has been observed in all the synthesized powder. Scanning electron microscopy (SEM) and energy dispersive Xray (EDX) analysis show the morphology and elemental analysis of as synthesized nanoparticles.TEM images confirms the spherical shape of the nanoparticles. HRTEM and SAED images show the crystalline nature and confirm the cubic nature of ZnS nanoparticles. Absorption study has been carried out by using UV-Vis spectrophotometer to determine the band gap of ZnS:Mn nanoparticles and they showed a blue shift with respect to the bulk. The effect of Mn 2+ substitution on the photoluminescence properties of doped samples is also studied and doped ZnS:Mn showed enhanced luminescence property compared with that of the undoped ZnS nanoparticles. Radius of the synthesized nanoparticles has been evaluated from the absorption spectrum by using the Effective Mass Approximation (EMA) formula. Fourier Transform Infrared Spectra (FTIR) is recorded in an FTIR spectrometer to verify the presence and effect of capping agent.

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Tin oxide (SnO 2 ) thin films are prepared by spin coating onto well-cleaned glass substrates using stannous chloride and methanol solution as complexing agent. Films of different thicknesses are annealed at 400 0 C. Optical properties are studied using UV-Visible spectrophotometer. The films are highly transparent in the visible region. It is found that transmission increases in coated glass (~92%) than uncoated glass. This may find applications in antireflection coating. Energy band gaps obtained are in the range of 4.10-4.12 eV. Refractive index variation with thickness is also studied and is between 1.77-1.91. The thicknesses of the film are of the order 2300, 3500 and 4800 Å. These results have been discussed in the light of literature.