Yahui Duan

Thin-Film Barrier Performance of Zirconium Oxide Using the Low-Temperature Atomic Layer Deposition Method

In this study, ZrO2 films deposited by the atomic layer deposition method, as the encapsulation layer for organic electronics devices, were characterized. Both the effects of tetrakis (dimethylamido) zirconium(IV) growth temperature and oxidants, such as water (H2O) and ozone (O3), were investigated. The X-ray diffraction analysis shows the amorphous characteristic of the 80-nm-thick films grown at 80 °C, the crystallinity of the films was much lower than those grown at 140 and 200 °C. The scanning electron microscopy analyses showed that the surface morphology strongly depended on the crystallinity of the film. The water vapor transmission rate of the 80 nm thick ZrO2 films can be reduced from 3.74 × 10(-3) g/(m(2) day) (80 °C-H2O as the oxidant) to 6.09 × 10(-4) g/(m(2) day) (80 °C-O3 as the oxidant) under the controlled environment of 20 °C and a relative humidity of 60%. Moreover, the organic light-emitting diodes integrated with 80 °C-O3-derived ZrO2 films were undamaged, and their luminance decay time changed considerably. This was attributed to the better barrier property of the low-temperature ZrO2 film to the amorphous microscopic bulk and almost homogeneous microscopic surface.

High-performance flexible Ag nanowire electrode with low-temperature atomic-layer-deposition fabrication of conductive-bridging ZnO film

As material for flexible transparent electrodes for organic photoelectric devices, the silver nanowires (AgNWs) have been widely studied. In this work, we propose a hybrid flexible anode with photopolymer substrate, which is composed of spin-coating-processed AgNW meshes and of zinc oxide (ZnO) prepared by low-temperature (60°C) atomic layer deposition. ZnO effectively fills in the voids of the AgNW mesh electrode, which is thus able to contact to the device all over the active area, to allow for efficient charge extraction/injection. Furthermore, ZnO grown by low temperature mainly relies on hole conduction to make the anode play a better role. Hole-only devices are fabricated to certify the functionality of the low-temperature ZnO film. Finally, we confirm that the ZnO film grown at a low temperature bring a significant contribution to the performance of the modified AgNW anode.

Improved performance for white phosphorescent organic light-emitting diodes utilizing an orange ultrathin non-doped emission layer

Efficient white phosphorescent organic light-emitting diodes with excellent stable spectra based on an orange ultrathin non-doped layer and a blue doped emission layer are reported. The emission color can be changed by adjusting the thickness of the 4,4′-bis(carbazol-9-yl)biphenyl (CBP) layer or the mixed ratio of CBP and 2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) in the mixed interlayer. On the basis of the mixed CBP:TPBi interlayer, we successfully fabricated a white device with superior stable spectra and lower turn-on voltage. Moreover, the white device with an optimum mixed ratio of 2 : 1 in the mixed interlayer has a power efficiency of 40.1 lm W−1, which is 2.1 times as high as that of the device with a pure CBP spacer.