Growth and characterization of sodium pentaborate [Na(H4B5O10)] single crystals.
The bulk single crystals of sodium pentaborate [Na(H4B5O10)] were grown by slow evaporation solution growth technique using deionized water as solvent. The grown crystal was confirmed by single crystal X-ray diffraction studies. The structural perfection of the grown crystals has been analyzed by high resolution X-ray diffraction (HRXRD) studies by recording rocking curve. The photoluminescence (PL), UV-vis spectral studies were performed and the optical bandgap of the material was calculated. The presence of the functional groups was identified by FT-IR measurement. The factor group analysis was done on Na(H4B5O10) to reveal the vibrational optical modes. The thermal and mechanical properties of the grown crystal were studied by TG-DTA and Vickers microhardness tester, respectively. The dielectric behavior of Na(H4B5O10) was investigated with different frequencies and temperatures.
Photoluminescent and photovoltaic properties observed in a zinc borate Zn2(OH)BO3
A chiral zinc borate Zn2(OH)BO3, which exhibits nonlinear optical, photoluminescent and photoelectronic properties, has been successfully prepared through a hydrothermal reaction. The structure of the compound has a ZnO matrix and the electronic structure of the compound can be regarded as that for ZnO modified by the presence of B atoms. The luminescence properties of Zn2(OH)BO3 were characterized by excitation and emission spectra. Photovoltage signals were observed for the as-synthesized compound and for samples calcined at various temperatures by surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS). The results show that Zn2(OH)BO3 has photoelectric transformation ability. Either thermal treatment or application of an external electric field enhances the photovoltage responses of the compound to a considerable extent.
Lattice Perturbations in CaWO4 and CaMoO4
Frequency assignments for the vibrational modes of species Bu in CaWO4 and CaMoO4 are made. Bu modes are both infrared inactive and Raman inactive in unstrained material, but become infrared active and exhibit Eu characteristics under xz or yz shear strain and Au characteristics under xy shear strain. In the present paper previously published infrared data are interpreted in terms of strain‐induced mode mixing, and the nature of the crystalline strain is discussed. The assignment of the three Bu modes in CaWO4 completes the task of identifying the 18 internal modes of the WO4= ions.