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We report the effects of dielectric surface properties on the device performance of organic thin film transistors (OTFTs) using polymer/high-k oxide multilayered gate dielectrics. We systematically controlled the surface energy of the gate dielectric from very hydrophobic to very hydrophilic. The modified dielectric surface strongly affected the initial growth mechanism of pentacene and subsequently the performance of the OTFTs. The performance of the OTFTs with a higher surface energy was superior to that of the OTFTs with a lower surface energy.

The authors have demonstrated efficient polymeric tandem organic light-emitting diodes (OLEDs) with a self-organized interfacial layer, which was formed by differences in chemical surface energy. Hydrophilic poly(styrene sulfonate)-doped poly(3,4-ethylene dioxythiophene) (PEDOT:PSS) was spin coated onto the hydrophobic poly(9,9-dyoctilfluorene) (PFO) surface and a PEDOT:PSS bubble or dome was built as an interfacial layer. The barrier heights of PEDOT:PSS and PFO in the two-unit tandem OLED induced a charge accumulation at the interface in the heterojunction and thereby created exciton recombination at a much higher level than in the one-unit reference. This effect was confirmed in both the hole only and the electron only devices.

We investigated Xe–N2 gas discharge primarily as a source of vacuum ultraviolet for florescent lamps. The discharge performances of Xe based nitrogen admixture gas are improved when compared with the results of pure Xe discharge. The experimental results come from investigating the Xe positive column and were determined by measuring the infrared radiation during the discharge operation. These results suggest that the integrated infrared area is increased by about 40% under optimal conditions. This efficiency increase occurs because low energy electrons contribute to the production of exited nitrogen, which can excite Xe gas.

The authors have developed a semitransparent, multilayered cathode of indium tin oxide (ITO)/Ag/tungsten oxide (WO3) for transparent organic light-emitting diodes. The device showed a weak negative differential resistance (NDR), until the operating voltage of 8V was reached. NDR was due to the resonant tunneling by both the quantum barrier and quantum well. The silver oxide (Ag2O) on the Ag metal was confirmed by x-ray photoelectron spectroscopy, and the energy levels of Ag2O were quantized due to the quantum size effect and this produced the resonant tunneling channels. The device using ITO∕Ag∕WO3 with a LiF∕Al bilayer was superior to those devices which only used ITO or WO3, mainly because the out coupling was enhanced by employing a WO3 material, which is much more transparent than ITO.

The authors derived an analytical relationship between rms tube current and input power for various capacitances of the external electrode part and measured their effective capacitances in an external electrode fluorescent lamp. From the fitting derived relation in the measured data, the reliability of the authors’ derivation was certain and effective capacitances were measured. Consequently, it is confirmed that the derived relationship is very useful in estimating the effective capacitance of the external electrode part for any shape of glass tube and electrodes during the lamp operation.

The authors introduced a concept of self-sensing neutralization system by means of automatically ejected charged particles from alternative current microhollow cathode discharge. When the positive bias was applied to the third electrode, a real current flow was only detected during negative polarity period of voltage applied to the first electrode. On the other hand, in the case of negative bias, there was only the real current during positive polarity period. These results mean that our system shows simultaneously the self-sensing and then neutralizing characteristics in a period.

We adopted the self-expanded microcapillary positive column from single microhollow cathode discharge as a high efficient vacuum ultraviolet (vuv) sources, employing one power supply circuit with a resistor for easily starting without an additional power supplier and investigated their electrical characteristics and the vuv radiant efficiency, varying the input power. The electrical measurements showed that the discharge passed through two distinct stages: the microhollow cathode discharges stage and the self-expanded microcapillary positive column stage. As a result, the vuv radiant efficiency of the self-expanded microcapillary positive column is about 17 times as high as that of the microhollow cathode discharges at the input power 1.2W.