Improvement of Flexible Organic Light-Emitting Diode Performances by Using an UV-Sensitive Layer

• Main Authors: Chung-ta Wu, 吳忠達
• Other Authors: Shu-hsiang Su
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/62144348808606799323

碩士 === 義守大學 === 電子工程學系碩士班 === 97 === In this study, transparent and conductive indium-tin oxide (ITO) thin films were deposited on polyethersulfone (PES) flexible plastic substrates by RF magnetron sputtering. The obtained optimum growth conditions for the room-temperature deposition are: RF power = 700 W, deposition pressure = 7 mtorr, and the gas of Ar (30 sccm). The ITO films grown on PES substrates exhibited a sheet resistance of 64 Ω/□, a resistivity of 1.16×10-3 Ω cm, a carrier concentration of 1.5×1020 cm -3, and the transmittance of 86%. The (211)、(400)、(440) peaks were observed from the XRD profiles. Then, flexible organic light-emitting diodes (FOLEDs) were fabricated indium–tin oxide (ITO) on PES substrate by using an UV-sensitive layer between PES substrate and ITO film. The structure of device is PES substrate /UV-sensitive layer/ITO/NPB (40 nm)/Alq3 (60 nm)/LiF (1nm)/Al (200 nm). The results show that an ITO film on PES substrate with an UV-sensitive layer has a much lower Rrms of 4.8 nm than that without UV-sensitive layer, which has a Rrms of 8.1 nm. With the assistance of UV-sensitive layer, the luminous efficiency of FOLED was enhanced from 4.2 to 4.49 cd/A at current density of 20 mA/cm2. Besides, the lifetime of FOLED with UV-sensitive layer is 32 hours at an initial luminance of 2000 cd/m2, and better than that of the device without UV-sensitive layer about 2 times.