A non-destructive Raman spectroscopy has been widely used as a complimentary method to X-ray diffraction characterization of Cu2ZnSnS4 (CZTS) thin films, yet our knowledge of the Raman active fundamental modes in this material is far from complete. Focusing on polarized Raman spectroscopy provides important information about the relationship between Raman modes and CZTS crystal structure. In this framework the zone–center optical phonons of CZTS, which is most usually examined in active layers of the CZTS based solar cells, are studied by polarized resonant and non-resonant Raman spectroscopy in the range from 60 to 500 cm−1 on an oriented single crystal. The phonon mode symmetry of 20 modes from the 27 possible vibrational modes of the kesterite structure is experimentally determined. From in-plane angular dependences of the phonon modes intensities Raman tensor elements are also derived. Whereas a strong intensity enhancement of the polar E and B symmetry modes is induced under resonance conditions, no mode intensity dependence on the incident and scattered light polarization configurations was found in these conditions. Finally, Lyddane-Sachs-Teller relations are applied to estimate the ratios of the static to high-frequency optic dielectric constants parallel and perpendicular to c-optical axis.

We show that when polystyrene is exposed (for 15-60 sec) to a UV laser light beam (λ = 248 nm), its absorption and luminescent properties change significantly. In the irradiated polymer, optical centers are formed with absorption bands in the 280-460 nm region and fluorescence bands in the 330-520 nm region. We have established the chemical structure of the optical centers for fluorescence of polystyrene.

Polymer films with small Ag-clusters and Ag-nanocrystals were obtained by the cocondensation of Ag and chloro-p-xylylene from the gaseous phase followed by low-temperature solid-state polymerization. UV-Vis spectroscopic data show that the annealing of films at ambient temperature and thereafter at 373 K leads to a sharp rise of the amount of Agnanocrystals by aggregation of small clusters, but the mean size iof the nanocrystals remains practically constant. According to X-ray data, the lattice of Ag-nanocrystals is close to that of metallic Ag and i i s equal to approximately 50 A.

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