The structural, electro-optical, charge transport and nonlinear optical properties of oxazole (4Z)-4-Benzylidene-2-(4-methylphenyl)-1,3-oxazol-5(4H)-one derivative

Abstract

The oxazole compounds are being used for multifunctional purposes ranging from organic light emitting diodes, organic thin film transistors, and photovoltaic to the nonlinear optical materials. In this study, several structural, electro-optical, charge transport and nonlinear optical properties of (4Z)-4-Benzylidene-2-(4-methylphenyl)-1,3-oxazol-5(4H)-one (BMPO) have been investigated. Density functional theory (DFT) and time dependent DFT are very accurate and reasonable approaches to optimize the ground and excited state geometries, respectively. Thus, in the present study DFT and TDDFT methods with the B3LYP/6-31G∗∗ levels of theory have been applied to shed some light on the structure-property relationship, frontier molecular orbitals (FMOs), optical properties. A clear intra-molecular charge transfer (ICT) from the highest occupied molecular orbitals (HOMOs) to the lowest unoccupied molecular orbitals (LUMOs) has been observed. The ionization potentials (IP), electron affinities (EA), total and partial densities of states have been discussed intensively. The electron reorganization energy of oxazole compound (BMPO) is smaller than the hole reorganization energy revealing that it might be good electron transport contender in OLED. The electron reorganization energy of BMPO is calculated to be 0.223eV that is smaller than the perfluoropentacene (value is 0.250eV), which is famous n-type semiconductor material. The first pathway of BMPO has almost comparable hole and electron transfer integral values whereas the calculated electron reorganization energy (0.223eV) is considerably lower than the hole reorganization energy (0.381eV) which leads to superior electron intrinsic mobility of the studied oxazole derivative as compared to the hole one. It is expected that BMPO might be excellent electron transport material.