Synthesis and investigation of linear and nonlinear optical properties of an octahedral metalloporphyrin

Metalloporphyrins are the natural light harvesting antennas and are extensively used as sensing and optoelectronic materials. Herein, we are reporting the synthesis and investigation of the optical properties of a novel octahedral metalloporphyrin, SnPMX. The structure of SnPMX is established by the IR, UV-visible, 1H NMR, and HRMS techniques. Thermal evaporation is used to grow thin films of SnPMX on quartz surfaces. The surface morphology and structural parameters of the as deposited thin films are investigated by the use of powder XRD and SEM. The linear and nonlinear optical parameters of the SnPMX are investigated by employing the WempleDiDomenico and Drude single oscillator models. The SnPMX presented a higher value of the lattice dielectric (epsilon L = 5.79) than the high frequency dielectric (epsilon infinity = 4.76) which confirmed the presence of free carriers and lattice vibrations. The short relaxation time (tau = 2.30 x 10-20 s), higher optical mobility (mu opt. = 9.19 x 10-9 C. Sec/Kg) and third order nonlinear susceptibility (chi 3 = 1.37 x 10-12 esu) support its potential use in optoelectronics and photonics. In the absorbing region, SnPMX presented 2.67 eV of direct optical band gap energy, and in the non-absorbing region, two distinct Urbach energies of 1.01 and 1.90 eV were observed, which indicate the electron-phonon or exciton-phonon interactions. These results indicate that SnPMX can be used for NLO and optical limiting applications.