Remarkable enhancement in optical and thermal properties of sodium hydrogen phthalate hemihydrate crystals due to Fe3+ doping

Effects of Fe-doping on the solution grown semi-organic non-linear optical sodium phthalate hemihydrate (SP) single crystals have been reported. The structure and morphology of pure and doped crystals were analyzed. The degree of dopant inclusion was ascertained by Atomic Absorption Spectroscopy. The vibrational bands of the crystals were elucidated by Fourier transform infrared and Raman spectra. Fe inclusion in SP crystals resulted in an absorption band at 370 nm in UV region and increase in transmittance in entire visible region with no appreciable change in optical band gap. Intensity of photoluminiscent peaks at 412 nm and 522 nm was enhanced due to Fe-doping with inhomogeneous broadening. Dielectric studies showed lower dielectric tensor component (ε33) and higher dielectric loss in Fe-doped crystals compared to pure SP crystals. Melting point and thermal stability enhanced due to the introduction of small ionic radius Fe3+ ion in the pure SP crystal. SHG efficiency of pure SP crystal was doubled after Fe-doping and became comparable to that of KDP.

► Morphology of solution grown SP crystals changed due to Fe-doping.
► Thermal stability and melting point increased in Fe-doped SP crystals.
► Absorption band at 370 nm in UV-region appeared for FSP crystals.
► PL intensity and SHG efficiency of SP crystals increased due to Fe-doping.
► Fe-doped SP crystals are better for holographic and optoelectronic applications.