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

Öz

In this research, 2, 6-bis (3- (carbazol-9-yl) phenyl) pyridine films were synthesized using spin coating to study changes in its optical properties for different annealing temperatures. The films were annealed at 30, 50, 70, 90, 110, 120, 140 and 160 ℃ degrees in the presence of nitrogen. The material studied is one of the basic materials of the organic light emitting diode and forms the light emitting layer. In the results obtained from the films, for UV ultraviolet region, the highest absorption was obtained at 50 ℃ annealing, while the lowest absorption was 160 ℃. Optical band gap energies of films range from 3.35 to 3.43 eV. Refractive index distributions depending on the annealing temperature of the films were studied in detail. The refractive indices of the films at 440 nm wavelength varied between 2.71 and 3.39 according to different annealing temperatures. It is observed that it varied between 3.06 eV and 3.19 eV. It was observed that in the visible region of the spectrum, refractive index of the films increased in a sharp linear behavior at a wavelength of 350 nm. Annealing took place in two regimes that increase and decrease the effect of the optical band gap energy of the film. It can be seen that the percentage of reflection of all films at the wavelengths after 500 nm was almost constant. It has been evaluated that the films had 70 % transmittance at 70 ℃ (up to 160 ℃) and after this point, their transmission (%) was above 70 % and films can be used in the permeability devices of this feature. As a 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 annealing temperature.

Anahtar Kelimeler

• Optical properties
• film
• annealing effects
• organic light emitting diode

Kaynakça

1. Cheah LB, Rozana AMO, Poopalan P, 2020. Ga2O3 thin films by sol-gel method its optical properties. AIP Conference Proceedings, 2203: 020028.
2. Chen D, Wang Z, Wang D, Wu YC, Lo CC, Lien A, Cao Y, Su SJ, 2015. Efficient exciplex organic light-emitting diodes with a bipolar acceptor. Organic Electronics, 25: 79-84.
3. Guo R, Zhang S, Yue S, Yan P, Wu Y, Qu D, Zhao Y, 2016. High efficiency and simplified white organic light-emitting diode based on a single-host emission layer. Synthetic Metals, 220: 329-333
4. Guo X, Yuan P, Qiao X, Yang D, Dai Y, Sun O, Qin A, Tang B, Ma D 2020. Mechanistic Study on High Efficiency Deep Blue AIE-Based Organic Light-Emitting Diodes by Magneto-Electroluminescence. Advanced Functional Materials, 30: 1908704.
5. Keshav B, Amit J, 2020. Fabricating gold nanorattles impregnated chitosan film for catalytic application. Materials Science for Energy Technologies, 3: 167-173.
6. Kim M, Lim C, Jeong D, Nam HS, Kim J, Lee J, 2016. Design of a MoOx/Au/MoOx transparent electrode for high-performance OLEDs. Organic Electronics, 36: 61-67.
7. Koh T, Cho W, Yun HC, Yoo S, 2012. ITO-free down-conversion white organic light-emitting diodes with structured color conversion layers for enhanced optical efficiency and color rendering. Organic Electronics, 13: 3145-3153.
8. Liang X, Wang K, Zhang LR, Guo K, Lu X, Wang K, Miao H, Xu H, Wang Z, 2017. Tetra-carbazole substituted spiro[fluorene-9,9′-xanthene]-based hole-transporting materials with high thermal stability and mobility for efficient OLEDs. Dyes and Pigments, 139: 764-771.

9. Lee Y, 1996. A Compact and Transmissive Device for Dispersion-Compensation of Ultra-short Optical Pulses. OPT REV, 3: 303–305.
10. Liu J, Li M, Lu Z, Huang Y, Pu X, Zhou L, 2020. Color tuning of iridium(III) complexes containing 2-phenylbenzothiazole-based cyclometalated ligands for application in highly efficient organic light-emitting diodes. Dyes and Pigments, 175: 108145.Mullemwar S.Y, Zade GD, Kalyani NT, Dhoble SJ, 2016. Blue light emitting P-Hydroxy DPQ phosphor for OLEDs. Optik - International Journal for Light and Electron Optics, 127: 10546-10553.
11. Skuodis E, Tomkeviciene A, Reghu R, Peciulyte L, Ivaniuk K, Volyniuk D, Bezvikonnyi O, Bagdziunas G, Gudeika D, Grazulevicius JV, 2017. OLEDs based on the emission of interface and bulk exciplexes formed by cyano-substituted carbazole derivative. Dyes and Pigments, 139: 795-807.
12. Tsai YS, Hong LA, Juang FS, Chen CY, 2014. Blue and white phosphorescent organic light emitting diode performance improvement by confining electrons and holes inside double emitting layers. Journal of Luminescence, 153: 312-316.
13. Wan M, 1992. Absorption spectra of thin film of polyaniline. Journal of Polymer Science Part A: Polymer Chemistry, 30: 543-549.
14. Wu ZG, Zheng YX, Zhou L, Wang Y, Pan Y, 2017. Suppression of efficiency roll-off in highly efficient blue phosphorescent organic light-emitting devices using novel iridium phosphors with good electron mobility. Organic Electronics, 42: 141-145.
15. Yu T, Deng L, Xia P, Lu Y, Zhan N, Chen S, 2019. Ultrahigh-performance blue organic light-emitting diodes based on SiO2 coated Ag nanocubes and its working mechanism. Organic Electronics, 75: 105388.
16. Zhao B, Miao Y, Wang Z, Chen W, Wang K, Wang H, Hao Y, Xu B, Xu W, 2016. Highly efficient orange fluorescent OLEDs based on the energy transfer from bilayer interface exciplex. Organic Electronics, 37: 1-5.
17. Zhao X, Zhou L, Jiang Y, Cui R, Li Y, Zhang H, 2016. Efficient organic blue fluorescent light-emitting devices with improved carriers' balance on emitter molecules by constructing supplementary light-emitting layer. Dyes and Pigments, 130: 148-153.
18. Zhou L, Jiang Y, Cui R, Li Y, Zhao X, Deng R, Zhang H, 2016. Efficient red organic electroluminescent devices based on trivalent europium complex obtained by designing the device structure with stepwise energy levels. Journal of Luminescence, 170: 692-696.