Recent efforts have been directed towards the fabrication of polymer nanocomposites containing nanometer-sized crystals of inorganic semiconductors because of their potential application as high technology materials. Semiconductor nanoparticles, in particular, have several optical properties, such as excellent photo stability, broad excitation spectra, and narrow emission spectra, which makes them suitable for future technological applications in various areas like non-linear optics, catalysis, solar energy conversion and optoelectronic devices. Particular interest in nanocrystalline PbSe (due to low band gap ~0.27 eV at 300 K) is due to its exceptionally large Bohr's exciton radius of about 46 nm, following which significant quantum size effects are readily observed in relatively large sized nanoparticles. Therefore, the authors have decided to prepare the PbSe nanocomposites via a single-step reaction process at room temperature. Polyvinyl alcohol (PVA) is chosen as the polymer matrix for its aqueous solubility. We have prepared PbSe nanorods embedded PVA films. These thin films have been characterized using TEM, XRD, FTIR and UV-Vis techniques. The TEM analysis shows that the particles formed are homogenously rod shaped and these are well dispersed in the polymer matrix and does not show any clumping. The dimensions of these nanorods are found to be much less than the Bohr's exciton radius of PbSe, indicating strong quantum confinement of charge carriers. The strong quantum confinement is further evident from the large blue shift in the optical band gap, studied using UV visible Spectrophotometer.
PbSe, Polyvinyl alcohol, XRD, TEM, UV-visible, FTIR
