Investigations on the growth and characterization of some technologically important crystals grown by solution growth technique

Abstract

Potassium pentaborate di-hydrate (KB5) [K(B5O6(OH)4).2H2O] and newlinesodium pentaborate di-hydrate (NB5) [Na(B5O6(OH)4).2H2O] single crystals newlinehave been found to be very interesting materials and several researchers have newlineshown much interest on these crystals. newlineIn order to understand the formation of proper single phased mixed newlinecrystals based on KB5 and NB5 and with an interest to discover new materials, newlinewe invesigated Pure KB5, Pure NB5 and, for the first time, mixed borate crystals newlineof type (KNB5 (x)) [K1-xNxB5 or NaxK1-xB5O6(OH)4.2H2O] (with x = 0.2, 0.4, newline0.5, 0.6 and 0.8) by the slow evaporation of solvent method. In addition, in order newlineto understand the effect of urea as an impurity on the structural, optical and newlineelectrical properties, we investigated (for the first time) by the slow evaporation newlineof solvent method urea doped (with three different impurity concentrations, viz. newline2.5, 5.0 and 7.5 wt%) KB5, NB5 and K0.5N0.5B5 crystals. All the sixteen crystals newlinegrown were structurally and chemically characterized by making SXRD, PXRD, newlineFTIR spectral and EDX spectral measurements, optically characterized by UVVis newlineabsorption spectral and SHG efficiency measurements, and electrically by newlineAC electrical measurements. The seven un-doped crystals grown were further newlinecharacterized by making AAS, TG/DTA, micro hardness and PL spectral newlinemeasurements. The solubilities in de-ionized water of the seven un-doped and newlinethree mixed-doped crystals were also measured at five different temperatures. newlineAll the sixteen crystals grown are found to be of considerable size, newlinetransparent, colorless, good quality and stable under normal atmospheric newlinecondition. Results of solubility measurement indicate that all the ten crystals newlineconsidered for the measurement are considerably soluble in water and exhibit newlinepositive temperature dependence for the solubility. Results of structural and newlinechemical characterization indicate that proper single phased mixed crystals are newlineformed even though the lattices of KB5 and NB5 crystals do not match. newline