This letter presents the optoelectrical performance of an organic light-emitting diode (OLED) through the elevation of indium tin oxide (ITO) anode work function by Ni co-sputter surface doping and additional O2 plasma treatment. The turn-on voltage of OLED devices can be reduced by 2.3V for Ni atomic concentration greater than 1.8% and by 2.7V for the additional O2 plasma treatment. Devices with Ni(2.6%)-doped and O2 plasma treated ITO anodes perform the highest luminance efficiency (0.91lm∕W), three times larger than undoped ITO (0.31lm∕W) at 250cd∕m2.

No abstract

No abstract

Titanium dioxide ͑TiO 2 ͒ films were grown on Ni-, Ta-, and Ti-coated glass substrates at temperatures between 200 and 500°C by atomic layer deposition ͑ALD͒ from TiCl 4 and H 2 O precursors. The as-deposited films were anatase crystalline at the deposition temperature of 200°C and became rutile crystalline with the increase in deposition temperature. The temperature for the transition of anatase to rutile varied with the substrate material; the Ni-coated substrate has the highest anatase-to-rutile transition temperature, followed by the Ta-coated substrate, and then the Ti-coated substrate. The grain size of as-deposited films had a minimum with deposition temperature for each substrate due to the composite effects of nucleus density and grain coalescence with temperature. The photocatalytic activity of ALD TiO 2 films for the decomposition of methylene blue was highly influenced by the growth characteristics and the underlying material. The 200 and 300°C deposited films on Ni-coated substrates possessed the highest photocatalytic activity among all experimental samples due to their pure anatase structure and the Schottky contact of Ni/TiO 2 .Titanium dioxide ͑TiO 2 ͒ has been widely used as pigments and optical coatings because of its nontoxicity, chemical stability, and high permittivity. In recent years, due to the discovery of its photocatalytic activity, the synthesis of TiO 2 for environmental purification and hydrogen evolution has become an attractive topic and is extensively studied. 1-5 TiO 2 in a particulate form is advantageous for surface reactions due to its large specific surface area. However, the difficulty in precipitating and recovering the TiO 2 particulates from water limits its application. In contrast, TiO 2 films are more practical for their stability and controllability. Many efforts have been devoted to deposit TiO 2 films on various substrate materials. [6][7][8][9] Several techniques have been used to deposit TiO 2 films, including sputtering, pulsed laser deposition, dip coating, spray coating, hydrothermal synthesis, metallorganic chemical vapor deposition, plasma-enhanced chemical vapor deposition, and atomic layer deposition ͑ALD͒. Among these techniques, ALD has received great attention due to its excellent uniformity, accurate thickness control, low deposition temperature, and almost 100% step coverage. 10-14 TiO 2 films with high surface area have been obtained by depositing a thin TiO 2 layer on high aspect ratio holes and porous substrates. 13,14 Although high surface area TiO 2 films can be prepared by ALD, their photocatalytic activity is inevitably influenced by the underlying materials and the growth characteristics of films. Dai et al. 15 investigated dip-coated TiO 2 films on Al alloy, glass, and indium-tin oxide glass and pointed out that the electron transfer between TiO 2 films and conducting substrates plays an important role in the photocatalytic degradation of organic pollutants. Miao et al. 16 investigated sputtered TiO 2 films and reported that only the films ...

No abstract