Positive Photoconducting Nature Research Articles

Crystal growth and characterization of L-valine cadmium acetate a semiorganic NLO crystals

A new semiorganic nonlinear optical material, L-valine cadmium acetate, was grown successfully from aqueous solution by slow evaporation method. The grown crystals characterized by using Powder X-ray diffraction analysis confirms the structure of the grown title compound. The functional groups have been identified using FTIR spectral data. Transmittance compound was analyzed by using UV-vis spectrum. The thermal behavior of the grown crystal was determined with the aid of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The dielectric constant was studied as a function of frequency for various temperatures. The grown crystal has positive photoconductivity nature. The fluorescence spectrum of the crystal was recorded and its optical band gap is about 3.4479eV. Second order nonlinear optical property of the grown crystal has been confirmed by modified Kurtz–Perry powder second harmonic generation (SHG) test.

Crystalline perfection, spectroscopic investigations and transport properties of trisglycine zinc chloride NLO single crystal

Bulk single crystals of trisglycine zinc chloride have been grown from aqueous solution by slow cooling technique. Single crystal and powder XRD analyses confirmed orthorhombic crystal structure with non-centrosymmetric space group Pbn2 1. High resolution X-ray diffraction results have established that the quality of the grown crystal is quite good for device fabrication. The crystal was characterized by FTIR and NMR spectral analyses. Optical absorption studies show that the material has very low absorption in the wavelength range 240–2000 nm. The analysis of absorption coefficient in the absorption region reveals a direct band gap of 4.21 eV. The crystal possesses remarkable thermal stability up to 229 °C. Photoconductivity studies of the grown crystal revealed the positive photoconducting nature. The grown crystal exhibited considerable hardness anisotropy with Vicker’s hardness tester. Dielectric constant and dielectric loss were calculated by varying frequencies at different temperatures.

Photoconductivity, dielectric and thermal investigations of pure, benzophenone- and iodine-doped benzoyl glycine NLO single crystals

Physical properties such as photoconductivity, dielectric and thermal stability have been investigated for pure benzoyl glycine (BG) crystals. In addition to this, the influence of dopants (benzophenone and iodine) of these properties on BG crystals has been studied. Photoconductivity studies on pure BG, benzophenone-and iodine-doped BG revealed the positive photoconducting nature. The dielectric responses of the samples have been studied in the frequency range 100 Hz–500 KHz at room temperature and the results are discussed in detail. The thermogravimetric studies of pure and doped BG crystals indicate that the presence of dopants has slightly increased the decomposition temperature of pure BG samples, thereby enhancing thermal stability to the doped ones.

Growth and characterization of a new nonlinear optical l-histidine acetate single crystals

Bulk single crystals of l-histidine acetate dihydrate (LHA), a new organic nonlinear material was successfully grown from aqueous solution for the first time by slow evaporation method. The solubility of LHA was determined in water and good optical quality single crystal of dimensions up to 21 × 13 × 9 mm 3 was obtained. The grown crystals were characterized by X-ray diffraction, FTIR, UV–Vis–NIR, microhardness and DTA/TGA studies. The SHG efficiency is found to be higher than that of KDP crystal. The dielectric constant and dielectric loss of the crystal were studied as function of frequency and the results are discussed. Photoconductivity studies of LHA reveal its positive photoconducting nature.

Growth and characterization of a novel NLO crystal l-histidine hydrofluoride dihydrate (LHHF)

Single crystals of l-histidine hydrofluoride dihydrate (LHHF), a semiorganic nonlinear optical (NLO) material have been successfully grown by slow evaporation technique. The crystals were characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR), UV-Vis-NIR, TGA, DTA, microhardness and solubility studies. The SHG efficiency of LHHF was found to be higher than that of KDP. The dielectric constant and dielectric loss of the crystal was studied as a function of frequency and the results are discussed. Photoconductivity studies carried out on the sample revealed its positive photoconductivity nature.

Thermal, dielectric and photoconductivity studies on pure, Mg2+ and Zn2+ doped BTCC single crystals

Single crystals of pure and doped bis(thiourea) cadmium chloride (BTCC) belonging to semiorganic nonlinear optical materials are grown by slow evaporation technique. The lattice parameters of the grown crystals are determined by single-crystal XRD. Single crystal XRD studies reveal that the incorporation of metallic dopants has not changed the structure of the parent crystal. The TGA traces of doped BTCC crystals indicate a marginal increase in the thermal stability of the samples. The response of dielectric constant in the frequency region of 500Hz to 500kHz has been investigated and the influence of metal substitution on the dielectric behaviour has been reported. Photoconductivity studies of pure and doped BTCC crystals revealed the positive photoconducting nature. Optical absorption studies indicate the low percentage of absorption of doped crystals in the visible region, thereby confirming the enhancement of NLO property.