Urea doped crystals formed with potassium–sodium pentaborate (K 0.5 Na 0.5 B5)

Abstract Mixed crystal formed with potassium and sodium pentaborates (K 0.5 Na 0.5 B5 crystal) is expected to be an interesting material. In order to understand the effect of urea as an impurity on the structural, optical and electrical properties of K 0.5 Na 0.5 B5 crystal, pure and urea doped (separately in 3 different concentrations, viz. 0.25, 0.50 and 0.75 wt%)K 0.5 Na 0.5 B5 single crystals were grown by the slow solvent evaporation method and characterized. X-ray diffraction (both single crystal and powder) and FTIR and EDX spectral measurements were carried out to characterize chemically and structurally the grown (pure + 3 urea doped) crystals. UV–Vis spectral and second harmonic generation (SHG) efficiency measurements were carried out to characterize the grown crystals optically. Dielectric measurements were carried out at various temperatures in the range of 30–90 °C with different frequencies in the range of 100 Hz–1 MHz. Results obtained indicate that urea doping enhances the optical absorption, window wavelength range and SHG efficiency of the K 0.5 Na 0.5 B5 crystal. Also, urea doping leads to significantly tuned electrical properties.