Effect of covalent linkage between hexagonal boron nitride and porphyrins on the optical nonlinearities

Abstract Nonlinear optical nanostructured materials are gaining increased interest as optical limiters for various applications. In the present case, two soluble porphyrins (TPP) covalently functionalized hexagonal boron nitride (h-BN) nanohybrids (BN-TPP 1 and BN-TPP 2 ) as optical limiter were prepared for the first time, and characterized by various spectroscopic techniques. The covalent attachment of porphyrins onto the surfaces of h-BN improves the ease of processing of these BN-porphyrins composite materials. The results of Z-scan measurements at 532 nm in the nanosecond laser pulse regime indicated that the BN-TPP nanohybrids exhibited markedly improved nonlinear absorption and optical limiting performances compared to a control sample consisting of a covalently unattached physical blend of h-BN and porphyrins, and the porphyrin covalently functionalized graphene nanohybrids, as well as to either h-BN or TPP alone. The enhanced optical nonlinearities can be ascribed to the synergetic effects originating from charge transfer between the two counterparts. The effects of porphyrins on the structure, thermal, linear and nonlinear optical responses of the h-BN were investigated in detail. The efficient nonlinear optical performances make the as-prepared nanohybrids excellent candidates for optical limiting applications.