Effect of doping cations Li(I)-, Ca(II)-, Ce(IV)- and V(V)- on the properties and crystalline perfection of potassium dihydrogen phosphate crystals: A comparative study

Abstract

The effect of doping metal ions with varied ionic charges (ranging from +1 to +5), Li(I)-, Ca(II)-, Ce(IV)- and V(V)- on the growth process and properties of potassium dihydrogen phosphate (KDP) crystals, grown by slow evaporation solution growth technique, has been investigated. Incorporation of metal ion into the KDP crystalline matrix is well confirmed by energy dispersive X-ray spectroscopy and atomic absorption spectroscopy. Interesting to observe that the incorporation is comparatively less in doping the higher valent metal. The powder XRD pattern and Fourier transform-IR analysis confirm the slight distortion in the structure of the KDP crystals as a result of metal ion doping. Slight changes in cell parameter values of doped KDP crystals are observed by single crystal XRD analysis. The high-resolution X-ray diffraction (HRXRD) studies used to evaluate the crystalline perfection reveal many interesting features on the ability of accommodating the dopants by the crystalline matrix. Surface morphological changes because of foreign metal ion incorporation are observed by scanning electron microscopy. UV-Vis spectroscopy reveals that the transparency is not affected much by the dopants and the cut-off wavelengths of all the doped specimens lie in a close range. Band-gap energies are estimated using optical transmittance data. Enhanced second harmonic generation efficiency is observed.