Study Of Blue Organic Light-Emitting Diodes By Adopting An Interfacial Layer

In recent years, organic light-emitting diodes(OLEDs) display began to use in the high-end display products has aroused extensive attention. Compared with cathode ray tube(CRT) and liquid crystal display(LCD), OELDs display has more prominent advantages. It can be fabricated in wide view-angle flexible displays with low power consumption and an excellent portability display, which are considered as the most promising next-generation display.Nowadays, the blue-light OLEDs have not been able to get the considerable color purity, brightness and efficiency compared with the green and red OLEDs, which seriously restricts the OLEDs applications in full color display applications. One of the most important factor restricting the blue-light device performance is the limited hole injection from anode to blue emitter which possesses very deep highest occupied molecular orbital energy level.For solving this problem, we propose and design a novel hole interface modifier material based on polymerization of hydroquinone and 2,4,6-trichloro-1,3,5-triazine(HQTZ). It is essential to sandwich new intermediate hole injection layer(HIL) between poly(3, 4-ethylene dioxythiophene): poly(styrene sulfonic acid)(PEDOT:PSS)/poly(vinylcarbazole)(PVK) for further enhancing deep-blue polymer device performance. We found that HQTZ is excellently compatible with PEDOT:PSS and PVK, and can further enhance the hole injection from ITO anode to PSF emitter. Cyclic voltammetry, ultraviolet-visible absorption spectrometry, photoluminescence spectrum, ultraviolet photo-emission spectroscopy, kelvin probe measurements, mobility test, atomic force microscope and scanning electron microscope were carried out to characterize the modifier material and devices.