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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The study and fabrication of top emission organic light-emitting diodes

Lin, Shin-Ju 27 June 2005 (has links)
The top emission organic light-emitting diodes (TEOLEDs) with multilayer electrodes were studied. Firstly a high reflectivity metal, Al, followed by a high work function metal, such as Pt, Ni or Au, was used as bilyaer anode. It was found that the Al/Au bilayer anode can give rise to a very good luminescent performance if the Al thickness in the bilayer was adjusted to 70 nm. The Al/Au bilayer anode has high reflectivity and good adhesive contact with the hole injection layer. Next the cathode in TEOLEDs composed of multiple layers, LiF/Al/Ag, were studied. The optimum thicknesses in each layer as 0.4/4/15 nm were used to achieve high transparency and good conductivity. The effects of thicknesses of each organic layer were also studied. When the optimum thicknesses of m-MTDATA/NPB/Alq3 were adjusted to 20/40/60 nm, the highest brightness and best luminance efficiency of 8041 cd/m2 and 3 cd/A, respectively, were obtained. The white TEOLED was also studied in this thesis. The ADS082BE was blue host-emitting material and DCJT was orange guest-emitting material. The doped concentration and location were adjusted to control the blue to orange luminance intensity ratio. A white emission with CIE coordinate (0.30, 0.34) was obtained. The highest luminance of 3739 cd/m2 @13.5 Vand best luminance efficiency of 3 cd/A@10V were obtained in the white TEOLED which used multilayer anode and cathode structures. Finally TEOLEDs were also fabricated on the Si wafer and flexible substrate. The brightness and luminance efficiency were (3894 cd/m2;3.8 cd/A on Si wafer),(575 cd/m2, 1.46 cd/A on PES substrate).
2

An OLED Pixel Driver Using Voltage Feedback for Threshold Voltage Shift Compensation

Wen, Cheng-neng 07 July 2008 (has links)
In this thesis we proposed two new pixel circuits for organic light emission display. The first one is 5T1C circuit with two control signals. It can compensate threshold voltage variation and the drop of the power supply voltage that result in OLED current non-uniformity. We have demonstrates that the pixel circuit has high immunity to the threshold voltage variation. In addition, the circuit uses low supply voltage compared with the conventional 5T1C pixel circuit, so it is a low power driver circuit. The second one employs the voltage feedback method and uses the gain value of design circuit for compensating the threshold voltage shift of the driving TFT.To the aim is to reach that to the flow through current of the driving TFT have no relationship with the threshold voltage of TFT. Thus, the OLED can emission light with retaining uniformity light in each time. Because the proposed circuit configuration has low supply voltage and low select pulse voltage, the spike wave phenomenon can be improved and eliminated while the circuit switchs on and off. Due to the circuit supply voltage is decreased, it power consumption reduce significantly and the capacitor charging time is less than 70 £gs. Thus, in this thesis, the two proposed pixel circuits are both of low voltage and low power. The two pixel circuits designed have been fabricated by TSMC 0.35£gm 2P4M CMOS technology with 3.3v power supply. The 5TIC chip area is 1031.8 ¡Ñ 1083.7£gm2 and the measured result shows that when the select pulse is 0~10V, the input voltage is 10V, the select pulse2 is 0~8V and the Vdata¡@voltage range is 0~5V, the OLED current is correspond to 0~20.6£gA and the maximum power consumption is 17£gw. The chip area of the voltage feedback circuit is 1083.38 ¡Ñ 1149.8£gm2 and the measured result shows that when the select pulse is 0~10V, the input voltage is 10V and the feedback resistor is 50£[, the power consumption is 72£gw and the charging time is 51.7£gs.
3

Development of top-emission Organic Light-Emitting Diodes for High luminance monochrome and full-colour microdisplay applications / Micro-écran OLED pour des systèmes optiques en projection

Gohri, Vipul 12 December 2012 (has links)
La travail présente traite du développement de diodes organiques électroluminescentes(OLEDs) a haute luminance pour des applications dans des micro écrans. Ces dispositifs sontbases sur des substrats silicium utilisent la technologie CMOS. Le présent ouvrage met en avantles efforts développe afin de réduire la dérive en tension et ma décroissance lumineuse enopération des dispositifs lumineux.Dans la première partie de l’étude, des OLEDs vertes haute luminance fonctionnant àbasse tension sont développes. L’empilement organique a émission vers le haut comprenant unémetteur fluorescent vert entre des couches de blocage de charges et des couches de transportdopées. Les effets de différentes structures de dispositifs, des configurations de l’empilement etdes matériaux organiques sur les performances initiales et en opération sont reportés ici.Dans la deuxième partie de l’étude, le développement de dispositifs OLED hybrides pourmicro écrans couleurs est présenté. Les structures hybrides comprennent une couche detransport de trous photosensible et traitable par solution (X-HTL) et d’une OLED blancheréalisée par évaporation sous vide. Cette méthode permet la génération de couleur directe, ellepermet ainsi d’obtenir de très bonnes efficacités et un contrôle aisé de la couleur émise parsimple modification de l’épaisseur de X-HTL. / The present work reports the development of high luminance organic light emitting diodes(OLEDs) device stacks for microdisplay applications. The devices are based on siliconcomplementary metal-oxide semiconductor (CMOS) backplane. In the present treatise effortsare particularly focused on reducing the luminance decay and the voltage drift during deviceoperation.In the first part of this study, high brightness and low operating voltage green OLEDs arereported. The top emitting device stack comprises of fluorescent green emitter accompanied bycharge blocking layers and doped charge transport layers. The effect of different devicestructures, configurations and organic materials on the initial and lifetime performance of thedevice is presented.In the second part of the study, device development of hybrid OLED stacks for high luminancefull color microdisplays is reported. The hybrid devices comprise of a solution processed andphotocrosslinkable hole transport layer (X-HTL) and an evaporated white OLED stack. Thismethod allows direct primary color generation with relatively high efficiency and offers ease ofcolor tunability by controlling the thickness of the X-HTL.

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