教師著作
Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/31266
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Item Efficiency Improvement of Organic Light Emitting Diodes with Co-Deposited Hole Blocking Layer(Trans Tech Publications, 2010-04-01) Liu, C. H.; Tesng, C. H.; Cheng, C. P.There are several kinds of methods in improving the efficiency of organic light emitting diodes (OLEDs). In this work, we used a co-deposited hole blocking layer to improve the efficiency of OLEDs. The structure of the component is: ITO/ MTDATA(15 nm) /NPB(40 nm) /BCP(10 nm) /BCP: Alq(15 nm) /LiF(0.7 nm)/ Al(180 nm). We changed the mixing rate of the BCP:Alq layer to be capable of hole blocking and electron transporting, and then improved the efficiency of OLEDs. Finally, we prepared white light OLED with doping Rubrene in NPB. When the concentration of the NPB: Rubrene layer was 2.0 wt.%, the device could emit the white light at 100 mA/cm2, and the luminance was above 2300 cd/m2, and the color coordinate was x = 0.36, y = 0.37.Item Influences of Dye Doping and Hole Blocking Layer Insertion on OLED Performance(Trans Tech Publications, 2010-04-01) Tesng, C. H.; Liu, C. H.; Cheng, C. P.This study presents the influences of dye doping and hole blocking layer insertion on the electroluminescent properties of the blue organic light emitting diode. The luminance of the device was significantly improved by BCzVB doping because of the utilization of effective F顤ster energy transfer and the improvement of carrier injection and trapping; a BCzVB dominant emission was observed. Furthermore, when a BCP layer was inserted between the TBADN:BCzVB and Alq3 layers, a thin BCP layer insertion enhanced the injection of electrons and improved the luminance of the device. In contrast, a thick BCP layer insertion caused a delay in electron transport, resulting in a decrease in current density and a deterioration in luminance.Item Friction stir welding of ductile iron and low carbon steel(Maney Publishing, 2010-11-01) Cheng, C. P.; Lin, H. M.; Lin, J. C.Friction stir welding (FSW) is a low distortion, high quality solid welding. There is no melting during the welding process, which results in improved welding quality. Ductile iron has the advantages of being low cost, of excellent castability, and of being good mechanically. Therefore, it is generally used in many structural engineering parts. In this study, ferritic ductile iron and low carbon steel were used to explore the qualities of dissimilar metal welding under different conditions. The FSW process, changes in the microstructure of the welding area and the mechanical properties of joints were explored. According to the research, we found that when dissimilar metal welding is conducted at 982 rev min-1 with a travelling speed of 72 mm min-1, flawless welding quality can be obtained if the stir rod rotates counterclockwise with carbon steel fixed in the advancing side and with ductile iron in the retreating side. FSW successfully provided defect free welds. However, fine pearlite and martensite structures appear in the stir zone, which result in mechanical property degradation of weldments. The stir zone in the weldments is very hard due to martensitic transformation. After heat treatment, the tensile strength improves, and the fracture site appears in the base metal of the carbon steel. However, the welding nugget is not completely filled when the stir rod directs ferritic ductile iron to the advancing side in the clockwise direction and carbon steel in the retreating side, which results in defects and lower welding quality.