Growth, optical, electrical, thermal, mechanical and NLO studies of pure and zinc acetate-doped l-threonine crystals

The field of optical studies benefits significantly from the development of non-linear optical crystals from aqueous solutions using the slow evaporation method. In the current research, pure and zinc acetate (ZA)-doped l-threonine crystals were produced, and they were characterized using a variety of characterization techniques. Powder X-ray diffraction analysis demonstrates the crystalline nature of the material. Calculated unit cell parameters reveal the crystals belong to the orthorhombic system. Crystal structure and space group of the grown crystals were determined from single X-ray diffraction analysis. Utilizing FTIR spectra, several functional groups found in the crystals were examined. The optical transparency of the generated crystals is determined by UV–visible spectral analysis, which reveals the high-optical transparency over the whole visible region, and the band gap energy of the grown crystals are 5.75 and 5.9 eV for pure and ZA-doped crystals. The emission coefficient, refractive index, optical conductivity, electrical conductivity, and optical electronegativity can also be calculated from the UV–visible spectrum. Good optical conductivity indicates that the grown crystals have high photoresponsiveness, and the optical electronegativity value of the grown crystals is below 1.7, revealing that the grown crystals are polar with covalent bonding. Dielectric studies were carried out to assess the electrical resistivity and conductivity of the developed crystals. The dielectric constant and dielectric loss are found to decrease with increasing frequency. The ac conductivity, ac resistivity, and activation energies of the grown crystals were calculated from dielectric studies. The TG/DTA curve has been utilized to figure out the thermal stability and melting point of the grown crystals. Doped crystals have higher thermal stability than pure crystals, and the stability is 230 °C for ZA-doped l-threonine crystals. The mechanical properties of the grown crystals, such as hardness number, elastic modulus, yield strength, Moh’s hardness number, and tensile strength, were determined from microhardness studies. ZA-doped l-threonine crystals have higher mechanical properties than pure crystals. Grown crystals belong to the soft material category found in the work-hardening coefficient. The ac conductivity, ac resistivity, and activation energies of the grown crystals were calculated from dielectric studies. The SHG efficiency was determined from NLO studies using KDP as a reference material. ZA-doped l-threonine crystals have SHG efficiency 1.7 times greater than that of reference KDP materials indicate that the grown crystals are applicable in the field of photonics.