Novel L-cysteine sodium formate single crystals <i>via</i> solution growth for multifunctional optoelectronic and nonlinear applications

A novel organic single crystal of L-cysteine sodium formate (LCSF) was successfully grown by the solution growth technique. Single-crystal X-ray diffraction confirmed its triclinic crystal structure, while FTIR and EDAX analyses verified the functional groups and elemental composition. SEM images revealed well-developed crystal morphology. UV–Vis–NIR studies showed a wide optical band gap of 3.8 eV with excellent visible transparency, supporting nonlinear optical applications. Photoluminescence exhibited strong emission, and TG/DTA confirmed thermal stability up to 225 °C. Cyclic voltammetry demonstrated promising electrochemical behavior, while SHG measurements showed an efficiency of 0.5 times that of KDP, indicating the crystal's potential for photonic, optoelectronic, and energy storage applications.