Deng Zhenbo

Improved performance of organic light-emitting devices with 2-(4-biphenyl)-5-(4-butylphenyl)-1,3,4-oxadiazole

Abstract The use of 2-(4-biphenyl)-5-(4-butylphenyl)-1,3,4-oxadiazole (PBD) as an anode buffer layer in organic light-emitting devices (OLEDs) with a configuration of indum tin oxide/α-naphtylphenyliphenyl diamine/8-hydroxyquinoline aluminum/LiF/Al has been studied. With PBD buffer layer several angstroms thickness, the current efficiency increased and the stability of the device was improved. The results suggested that PBD is a promising anode buffer layer for OLEDs. After Compared it with the TiO 2 buffer layer, TiO 2 and PBD are good candidates for hole-injecting buffer layer. And PBD buffer layer shows better operational durability and life.

A New Kind of Buffer Layer of TiO2 Self-Assembled Material in Organic Electroluminescent Devices

A new kind of TiO2 self-assembled nanometre material has been fabricated and is used as a hole-injecting buffer layer in organic electroluminescent devices. The luminance and the efficiency of a device individually rises from 1500 cd/m2 to 5000 cd/m2 and from 2.0 cd/A to 3.92 cd/A at the current density of 100 mA/cm2. The enhancements in brightness and efficiency are attributed to an improved balance of hole and electron injections due to blocking of the injected holes by the buffer layer and a more homogeneous adhesion of the hole transporting layer to the anode.

Enhanced brightness of Eu3+ complex in organic electroluminescent devices by using another rare-earth ion

Rare-earth ions Tb3+ and La3+ were used as a bridge to improve the energy transfer from the polymer to an Eu complex. The material Tb(La)0.5Eu0.5(BSA)3phen was synthesized and used as the emission layer in the device: ITO/PVK:Tb(La)0.5Eu0.5(BSA)3phen/Alq/Al. The two device were compared in detail and it was found that the device using La0.5Eu0.5(BSA)3phen as the emission material had better monochromatic characteristics with the maximal brightness of 102 cd/m2 and the colour coordinates x = 0.55 and y = 0.36.

Light Emitting Diode Based on Tb(AcAc)3Phen

A diode with Tb(AcAc)3Phen as the emitting layer and PPV, Alq3 as the hole and electron transporting layers was demonstrated. The emission of the diode had the unique line spectrum of pure Tb3+. The injected electron and hole recombination region was discussed.

Electroluminescence of polymer doped with triphenyl-2-pyrazoline

Poly-phenylquinoxaline is used as the electroluminescent(EL) materials to fabricate the thin film electroluminescent devices by the spin coating method. Doped with 1, 3, 5-triphenyl-2-pyrazoline, the EL spectrum of the devices is shifted to the blue-green region with its peak located at 465nm. The incorporation of a hole transport layer, poly-vinylcarbazole, will enhance the EL intensity, and the quantum efficiency is estimated to be 0.2%. Thus, the devices can be driven by either positive or negative bias (or ac voltage) even though the currentvoltage curve possesses a rectifying property.