Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath depo...Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition(CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to(040) plane of SnS. These observations were further confirmed by Raman analysis. FTIR spectra showed the absorption bands which corresponds to PVA in addition to SnS.The scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. The optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ～10~5 cm^(-1). A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. The observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. The optical band gap values were also used to calculate particle size and the results are discussed.展开更多
In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also invest...In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-con-ductive surface.展开更多
文摘Tin monosulphide(SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition(CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to(040) plane of SnS. These observations were further confirmed by Raman analysis. FTIR spectra showed the absorption bands which corresponds to PVA in addition to SnS.The scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. The optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ～10~5 cm^(-1). A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. The observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. The optical band gap values were also used to calculate particle size and the results are discussed.
文摘In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-con-ductive surface.
