Zugl.: Erlangen, Nürnberg, Universiẗat, Diss., 2003.

Zugl.: Erlangen, Nürnberg, Universiẗat, Diss., 2002.

Zugl.: Erlangen, Nürnberg, Univ., Diss., 2009

Zugl.: Braunschweig, Techn. Univ., Diss., 2008

It has been found that the results of 1,3,5-Tri(1-pyrenyl)benzene (TPB3) on the processing conditions of different depositon rates affect the morphology of thin films and the electroluminescent performance of the devices. At TPB3 deposition low rate, the average roughness of TPB3 thin film was much smoother comparing to high rate, the surface approached morphology and the wavelength peak was around 508nm. At TPB3 deposition high rate, the surface approached amorphous and the wavelength peak was around 476nm. Take advantage of varing deposition rates with different spectra to apply for colorful OLEDs. This research includes three parts as mentioned: (1) red organic light-emitting devices and (2) green organic light-emitting devices and (3) white organic light-emitting devices. In order to overlap perfectly between the host and dopant materials, we fabricated the red organic electroluminescent devices incorporating TPB3 at deposition low rate as the host material and 4-(dicyanomethylene )-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as red light-emitting dye and the green organic electroluminescent devices incorporating TPB3 at deposition high rate as the host material and 2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-10(2- benzothiazolyl)quinolizine-[9,9a,1gh]coumarin (C545T) as green light-emitting dye, respectively. First, we deposited TPB3 at the lower rate of 0.1 Å/sec as the host material doped the red dopant, DCJTB, for making red OLEDs. The device: ITO(130nm)/NPB(65nm)/TPB3: 2% DCJTB(40nm)/Alq3(30nm) /LiF(0.8nm)/Al(200nm) exhibited a maximum luminance at 13.5V of 70600 cd/m2, ca. four times higher than that of the device using Alq3 as the host material at the same potential. The maximum current and power efficiencies were 4.83 cd/A and 3.7 lm/W, respectively. The current and power efficiencies were greater than 4 cd/A and 1 lm/W, respectively, over the large range of potentials (3.5~13.5V) with good Commission Internationale de l¡¦Eclairage (CIE) coordinates of (0.63,0.37). These results indicate that searching for a suitable host material is a promising approach toward achieving high-efficiency red OLEDs. The second, we deposited TPB3 at the higher rate of 3.0 Å/sec as the host material doped the green dopant C545T in order to overlap perfectly between them for spectra in green OLEDs. The device: ITO(130nm) /NPB(65nm) /TPB3: 1%C545T(40nm) /Alq3(30nm) /LiF(0.8nm) /Al(200nm) exhibited a maximum luminance at 11.5V of 166000 cd/m2, it¡¦s higher than that of the device using Alq3 as the host material at the same potential. The maximum current and power efficiencies were 10.0 cd/A and 6.67 lm/W, respectively. The current and power efficiencies were greater than 7.98 cd/A and 2.28 lm/W, respectively, over the large range of potentials (4.0~11.0V) with good Commission Internationale de l¡¦Eclairage (CIE) coordinates of (0.31, 0.61). These results indicate that TPB3 OLEDs are good than Alq3 OLEDs.. For TPB3 white OLEDs, we deposited TPB3 at the higher rate of 3.0 Å/sec as the host material doped the red dopant DCJTB in order to make high color purity white OLEDs. The device: ITO(130nm) /NPB(65nm) /TPB3: 0.05%DCJTB(40nm) /Alq3(30nm) /LiF(0.8nm) /Al(200nm) exhibited a maximum luminance at 11.5V of 55690 cd/m2, the maximum current and power efficiencies were 4.57 cd/A and 3.01 lm/W, respectively. The current and power efficiencies were greater than 3 cd/A and 0.91 lm/W, respectively, over the large range of potentials (3.5~11.5V) with good Commission Internationale de l¡¦Eclairage (CIE) coordinates of (0.34 , 0.34)~(0.33 , 0.33). These results indicate that TPB3 white OLEDs have good luminance and color purity.

We have investigated the electrical properties of red organic light-emitting diodes (OLEDs) featuring a conventional structure comprising N,N¡¦-bis-(1-naphthl)-diphenyl -1,1¡¦- biphenyl-4,4¡¦-diamine (NPB) as the hole transporting layer (HTL) and 8-hydroxy -quinoline aluminum (Alq3) as the electron transporting layer (ETL). There are many methods for improving the efficiency of OLED with a configuration of ITO/NPB/Alq3/LiF/Al, such as increasing electron mobility of Alq3 or decreasing hole mobility of NPB. We can¡¦t obtain such improvement of the efficiency in the OLEDs composing Alq3:DCJTB as the emitting layer. From the measurement of hole-only and electron-only devices, the electrical characteristics such as hole concentration is greatly changed after doped DCJTB to Alq3 as the emitting layer. In our study, we also found that the efficiency increased upon the decreasing the deposition rate of NPB, presumably because the improved packing of NPB enhanced the carrier mobility, which therefore improve the carrier recombination rate. We deduced that the emitting layer of the device will become electron rich when the Alq3 is doped by DCJTB. It means that if we want to improve the efficiency of the red OLED, with Alq3:DCJTB as the emitting layer, we have to increase the hole concentration in the device. A red OLED device having the configuration of ITO/NPB/Alq3/LiF/Al exhibited a current efficiency of 7.4 cd/A at 20 mA/cm2 with Commission International de l'Eclairage coordinates of (0.62, 0.38). The current efficiency reached to 10.8 cd/A by putting optical film, which is a 50% improvement.

Indium Tin Oxide (ITO) films were deposited onto the flexible substrate as the conductive electrode of the flexible display. ITO films were deposited by RF reactive magnetron sputtering. We changed process conditions, such as RF power, process pressure and substrate temperature to get good optical and electrical properties. ITO films with good electrical and optical properties have been obtained. The sheet resistance of the ITO films (150nm) was below 30 £[/¡¼ under low temperature and low power process condition. The (211)¡B(400)¡B(440) peaks were observed from the XRD profiles. The UV-visible spectra indicate that the average optical transmittance of ITO films is around 80% in the visible range. The surface roughness of the ITO films is also good.

Zugl.: Braunschweig, Techn. Univ., Diss., 2007

University, Diss., 2006--Würzburg. / Erscheinungsjahr an der Haupttitelstelle: 2005.

Techn. Universiẗat, Diss., 2005--Darmstadt.