The authors have demonstrated highly efficient white organic light-emitting diodes (WOLEDs) by using two emissive materials as a dopant, 1,4-bis[2-(7-N-diphenyamino-2-(9,9-diethyl-9H-fluoren-2-yl)) vinyl] benzene (DAF-ph) and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2′) acetylacetonate ((acppy)2Ir(acac)). It was found that the OLED fabricated in this study emitted a white color consisting of three primary colors (red, green, and blue). The luminance-voltage (L-V) characteristics of the WOLEDs showed the maximum luminance of 30500cd∕m2 at 14V and the maximum luminous efficiency of 38.0cd∕A, respectively. The CIEx,y coordinates of the WOLED also showed (x=0.33, y=0.40) at 10V.

Amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with a solution-processed polymeric gate dielectric of cross-linked poly(4-vinylphenol) (c-PVP) film were fabricated on a poly(ethylene terephthalate) (PET) substrate on which an a-IGZO film, as the active channel layer, was deposited by radio frequency (RF) sputtering. The entire TFT fabrication process was carried out at a temperature below 110 °C. The device exhibited an on/off ratio of 1.5×106 and a high field-effect mobility of 10.2 cm2 V-1 s-1, which is, to our knowledge, the best result ever achieved among a-IGZO TFTs with polymeric gate dielectrics on a plastic substrate.

No abstract

No abstract

ZnO-based transistors were solution-processed using ∼3.6 nm sized ZnO quantum dots (QDs). Spin-deposited ZnO QD layer was annealed to remove QD capping organic molecules and to increase the connectivity of adjacent QDs. The resulting QD layer was highly transparent and crack free without any noticeable pores. 600 °C annealing of QD channel layer resulted in the highest electrical performances of bottom-gate QD-based transistors. A small quantity of Sn doping into the QD channel layer was found to be effective in further improving the electrical characteristics of the QD-based transistor, in particular exhibiting a higher field-effect mobility (0.282 cm2 V−1 s−1) by more than 4 factors than that of an undoped QD-based one. Finally, a fully transparent Sn-doped QD-based device was demonstrated by sputter deposition of Ga-doped ZnO as source–drain transparent electrodes and its electrical properties were evaluated.