Theoretical and Experimental Investigation on 1,2,3-Benzotriazole 4-Hydroxybenzoic Acid (BTHBA) Single Crystals for Third-Order Nonlinear Optical (NLO) Applications

1,2,3-Benzotriazole 4-hydroxybenzoic acid (BTHBA) is synthesized and single crystals of dimension 20 mm x 9 mm x 5 mm are grown from methanol solvent by conventional solution growth method. Single crystal X-ray diffraction data show that BTHBA belongs to the orthorhombic crystallographic system with non-centrosymmetric space group Pna21. The grown organic nonlinear optical (NLO) crystal is subjected to various characterizations like powder X-ray diffraction, UV-vis-NIR, photoconductivity, thermogravimetric differential thermal analysis (TG-DTA), and chemical etching analysis. Optimization of the molecular structure, highest occupied molecular orbital-lowest unoccupied molecular orbital energy, natural bond orbital analysis, molecular geometry, and molecular electrostatic potential are investigated using Gaussian 09w software. The laser damage threshold value of BTHBA crystal is estimated to be 13.4 GW cm(-2) using a Nd:YAG laser. The third-order NLO susceptibility of BTHBA crystal reveals relatively high values of about 8.95 x 10(-9) esu when compared with that of standard potassium dihydrogen phosphate (KDP) (8.3 x 10(-14) esu). Hence it can be effectively employed for various optoelectronic and photonic applications.