Shedding light on static and dynamic hyperpolarizabilities of thia[7&8]circulenes, toward their NLO applications

Herein, we examined optoelectronic properties of thia[7&8]circulenes ( 1 - 18 ). Although Circulenes are the elemental building blocks of well-known nanomaterials such as graphene, nanotubes, and fullerenes. Organic chemists have given attention to circulenes during their studies for the improvement and development of aromaticity concept, but NLO properties of these structure-forming circulene subunits are not properly studied. The considered compounds ( 1 - 18 ) are thermodynamically, kinetically and chemically stable. Nonlinear optical (NLO) response is evaluated through static and frequency dependent first and second hyperpolarizabilities analyses. The static first hyperpolarizability ( β o) of these compounds ranges between 0.00 – 496.54 au. The frequency dependent coefficients for all thia[7 & 8]circulenes show remarkable enhancement at 532 and 1064 nm, respectively. The nonlinear refractive index is increased up to 1.13×10−14 au for circulene 9 among all thia[7 & 8]circulenes at 532 nm. These findings successfully demonstrated that thia[7&8]circulenes nonlinear optical response can be increased by decorating multiple sulfur atoms. The unsymmetrical distribution of sulfur atoms is more effective as compared to symmetrical distribution.