Chemical Physics Review

The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of organic dye sensitizer 1,4-Phenylenediacetonitrile was studied based on ab initio HF and Density Functional Theory (DFT) using the hybrid functional B3LYP. Ultraviolet-visible (UV-Vis) spectrum was investigated by Time Dependent DFT (TDDFT). Features of the electronic absorption spectrum in the visible and near-UV regions were assigned based on TDDFT calculations. The absorption bands are assigned to ???* transitions. Calculated results suggest that the three excited states with the lowest excited energies in 3-Thiophenecarbonitrile is due to photo induced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer 3-Thiophenecarbonitrile, is due to an electron injection process from excited dye to the semiconductor’s conduction band. The role of cyanine and methyl group in 3-Thiophenecarbonitrile in geometries, electronic structures, and spectral properties were analyzed.

The photoluminescence properties of Eu2+ doped BaB2O4 prepared by novel solution combustion synthesis technique are investigated. The structure of the prepared sample characterized by TG-DTA, XRD and FTIR. Surface morphological study was done using SEM images. BaB2O4:Eu2+ gives strong emission at 380 nm (UV-A region), upon excitation with 322 nm light. The concentration of Eu2+ (relative to Ba) in BaB2O4 for which the quenching occur was found to be about 6 mol%, and the critical transfer distance for this concentration was calculated to be 14.56 Å. This phosphor may provide an efficient kind of luminescent material for various applications in medical & industry.