Experimental and theoretical investigation of linear and nonlinear optical properties of ethyl‐3‐hydroxy‐2‐napthoate azo dyes by solvatochromic, computational aspects, and Z‐scan technique
Sagar B. Yadav, Sohan Taware, Mavila C. Sreenath, Subramaniyan Chitrambalam, I. Hubert Joe, Nagaiyan Sekar
Abstract
Abstract To investigate the effect of substituents in azo dyes on their nonlinear optical properties, four azo dyes were synthesized using ethyl‐3‐hydroxy‐2‐naphthoate as a coupler and characterized. The polarizability ( α ) and hyperpolarizability ( β and γ ) constants were determined by using solvatochromic and computational method. A group of global hybrid and range seperated hybrid functionals having different Hartree‐Fock exchange percentage were used to evaluate the NLO properties. The functional ωB97 and ωB97XD performed better in the determination of polarizability ( α ) and hyperpolarizability ( β and γ ), respectively. The observed results for polarizability and hyperpolarizability parameters were supported by highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) energy gap, Hammett‐coefficient (σ), excited‐state coefficients (σ ex ), and hyper‐hardness (Γ) values. Third‐order NLO properties were analyzed by using Z‐scan technique. The –OCH 3 substituted dye 4d shows higher value of molecular susceptibility (χ (3) ), polarizability ( α ), and hyperpolarizability ( β and γ ) parameters among the studied azo dyes. They are likely to have the potential applications in optoelectronics and photonics.