The effects of annealing temperature on optical properties of 2, 6-bis (3- (carbazol-9-yl) phenyl) pyridine films

Abstract

In this research, 2, 6-bis (3- (carbazol-9-yl) phenyl) pyridine films were synthesized usingspin coating to study changes in its optical properties for different annealing temperatures. The filmswere annealed at 30, 50, 70, 90, 110, 120, 140 and 160 ? degrees in the presence of nitrogen. Thematerial studied is one of the basic materials of the organic light emitting diode and forms the lightemitting layer. In the results obtained from the films, for UV ultraviolet region, the highest absorptionwas obtained at 50 ? annealing, while the lowest absorption was 160 ?. Optical band gap energies offilms range from 3.35 to 3.43 eV. Refractive index distributions depending on the annealing temperatureof the films were studied in detail. The refractive indices of the films at 440 nm wavelength variedbetween 2.71 and 3.39 according to different annealing temperatures. It is observed that it varied between3.06 eV and 3.19 eV. It was observed that in the visible region of the spectrum, refractive index of thefilms increased in a sharp linear behavior at a wavelength of 350 nm. Annealing took place in tworegimes that increase and decrease the effect of the optical band gap energy of the film. It can be seenthat the percentage of reflection of all films at the wavelengths after 500 nm was almost constant. It hasbeen evaluated that the films had 70 % transmittance at 70 ? (up to 160 ?) and after this point, theirtransmission (%) was above 70 % and films can be used in the permeability devices of this feature. Asa result, the optical properties of films (bandgap energy, absorption band edge energy, refractive index,refractive (%), and transmission (%), etc.) were measured and evaluated according to the annealingtemperature.