Trypan blue dyed TGS crystal: Morphological, optical, thermal, mechanical, and ferroelectric properties

Abstract

Tri-glycine sulfate (TGS) single crystals were synthesized using the slow evaporation method, with samples prepared both undoped and doped with 0.1 mol% trypan blue (TB) dye. The external morphology of the crystals, both doped and undoped, was analyzed using the Bravais–Friedel–Donnay–Harker (B–F–D–H) model. Structural characteristics were examined through Fourier Transform Infrared (FTIR) spectroscopy and powder X-ray diffraction (XRD). UV–Vis–NIR spectral analysis revealed an optical transparency of approximately 65 % for both crystal types, with band gap energies of 5.20 eV for undoped TGS and 5.02 eV for TB-doped TGS. The inclusion of TB dye enhanced the mechanical hardness, thermal stability, and melting point of the TGS crystals. Piezoelectric studies showed a significant increase in the piezoelectric coefficient (d₂₂) from 53 pC/N in undoped TGS to 82 pC/N in TB-doped TGS. Precise remnant polarization was calculated for the doped crystal using the “Remnant Hysteresis Task,” highlighting minimal contributions from non-switchable factors. Comparative investigations of thermal, ferroelectric, optical, and mechanical properties demonstrate that TB-dyed TGS crystals outperform their undoped counterparts, suggesting their potential for advanced ferroelectric and electro-optic applications.