Electrical and optical properties of an organic semiconductor metal-free phthalocyanine (C32H18N8)

In a recent work we calculated some electronic properties of metal-free phthalocyanine such as band structure, density of states and energy gap. We have also presented some optical properties such as dielectric function, electrical loss function, optical conduction, absorption and refractive index, some of which have never been studied before. Calculations were performed in the framework of density functional theory (DFT), using the full-potential linearized augmented plane wave (FP-LAPW) method. This study presents the electrical gap energy of metal-free phthalocyanine to be E-g = 2.4 eV which is in good agreement with experimental data. A trap energy level is also observed. Optical band gap is about 2.48 eV with an optical trap level at 1.48 eV. In addition, we obtained the static refractive index in the x-, y- and z-directions as n(0xx) = 2.43, n(0yy) = 2.06 and n(0zz) = 2.32. Finally, absorption spectra display the existence of strong absorption bands at the wavelengths of 400 and 800 nm which compare favorably with experimental results.