Illumination effect on the structural and optical properties of nano meso nickel (II) tetraphenyl-21H, 23H-porphyrin films induces new two hours photo bleached optical sensor

Abstract

250nm thickness of meso nickel (II) tetraphenyl-21H, 23H-porphyrin, NiTPP films were prepared by thermal evaporation technique on a quartz substrate. The prepared films were illuminated for 10, 20, 30, 60, 120, 240, 360 and 420min. Films of 120 and 240min of illumination time had been affected while others had no response. The as prepared meso NiTPP films are amorphous and the illuminated one are crystalline with amorphous background included within nano scale. The illuminated films were accompanied by photo bleaching effect. Two gaps could be distinguished; indirect optical gap,Egiopt and the fundamental energy gap, Eg. Optical parameters; refractive index, absorption coefficient, single-oscillator energy, dispersion energy, Lattice dielectric constant, the ratio of the carrier concentration to the effective mass, optical conductivity and energy loss function were studied. All mentioned parameters were affected by the illumination time. The response of nano meso NiTPP films to the mention illumination time has pulse shape, so it is recommended to be used as optical sensor.