Sustainable design of Barium(II) chloride glycine semi-organic crystals with enhanced third-order nonlinear optical response for energy-efficient photonic applications

Single crystals of Barium(II) chloride–glycine semi-organic monohydrate (BCGM) were successfully synthesised using a slow evaporation solution growth method with water as the solvent. The crystal belongs to the orthorhombic system with a Pbcn space group, and the unit cell parameters are a = 8.310 Å, b = 14.840 Å and c = 9.320 Å, and angles α = β = γ = 90°. Spectroscopic and optical analyses confirmed the structural purity and formation of the crystal. FT-IR and FT-Raman spectroscopic analyses revealed vibrational modes corresponding to O–H, NH3+, N–H, C–N and CH2 groups, confirming the presence and bonding nature of glycine and water molecules in the crystal lattice. X-ray photoelectron spectroscopy (XPS) analysis confirmed the elemental composition and chemical states of Ba, Cl, C, N and O atoms. The UV–visible spectrum showed a strong absorption at 352 nm and a wide optical range. Furthermore, optical susceptibility and polarizability analyses revealed a nonlinear rise near the absorption edge, supporting the material’s strong NLO response. Photoluminescence analysis and deconvolution Gaussian fitting revealed emission peaks at 359 and 380 nm. The CCT value calculated from the CIE diagram is equal to 2919.58 K, which signifies warm white light. The third-order nonlinear optical susceptibility (χ3) was measured as 6.5 × 10−6 esu, indicating a substantial enhancement compared to previously reported glycine-based NLO crystals. The energy calculated quantities of optical susceptibility as well as polarizability have demonstrated the prospect of the BCGM crystal to be applied in laser frequency conversion. This study contributes to sustainable development by advancing energy-efficient photonic materials through eco-friendly crystal growth and enhanced nonlinear optical performance