| Organic light emitting devices (OLED) has gained a rapid development recently. It is technically crucial in the field of plate panel displays in the future. However, most of white OLEDs, so far, are fabricated with multilayer structures, which results in the complication of fabrication process and decline of quantum efficiency. So these devices are not suitable for the purpose of large-scale industrial manufacture. But the most important superiority of OLED is that it can realize flexible displays—flexible organic light emitting devices(FOLED).In this paper, firstly, FOLED with ITO/PVK:TPD/Alq3/Al configuration prepared on PET substrates were fabricated. The curves of the Current density-Voltage, Optical current-Voltage and Quantum efficiency-Current density of the devices were investigated. Compared to those with glass substrates fabricated under the same conditions, the opening voltage of the FOLED was a little higher than them, but those characteristics of two kinds of devices were very similar. Under the driving voltage of 20V, the corresponding brightness and quantum efficiency were 1000cd/m2 and 0.27%.Bis-2-(2-hydroxyphenyl)benzothiazolate)zinc (Zn(BTZ)2) is one of the best white electro- luminescent materials used OLED. In this paper, PET slice coated with ITO was used as substrate of FOLED. We used Zn(BTZ)2 as main light-emitting material and fabricated a new type of flexible organic white-light-emitting devices. The configurations of the devices were as follows: PET/ITO/PVK:TPD/Zn(BTZ)2/Al. The bright and steady light emitting had been obtained, and the brightness of the devices came to 1000cd/m2 (at a driving voltage of 25V). We also measured the CIE coordinates of the above devices, which were (x = 0.242, y = 0.359), and corresponding quantum efficiency value was 0.25%. Then the Rubrene was doped in Zn(BTZ)2(doping rate 0.05%), and the configurations of this devices were as follows: ITO/PVK:TPD /Zn(BTZ)2:Rubrene /Al. The brightness of the devices came to 1200cd/m2 (at a driving voltage of 25V), and the CIE coordinates of the above devices were(x = 0.339, y = 0.339), and corresponding quantum efficiency value was 0.35%. we also discussed the emitting mechanism of the material and the devices.Besides those, we also discussed the luminescence mechanisms and the capability of the devices curved. The reasons which caused the failure of the devices were analyzed. Lastly, three kinds of encapsulated material were used to envelop FOLED, and the lifetime of three kinds devices was studied and compared. Although lifetime of our enveloped devices was far less than commercial standard, it had made a remarkable progress. And then , the alloy Mg:Ag was used to substitute the Al anode, which improved the performances of FOLED. We believe the commercial OLED is not far away from us. |
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