Threshold voltage shifts of a-IGZO TFTs on plastics against biastemperature stress were successfully reduced below 0.03 V, equivalent to those on glass substrates. We have developed an 11.7inch qHD (960×RGB×540) flexible bottom-emission active-matrix organic light-emitting diode (AMOLED) driven by a-IGZO TFT backplane fabricated on a transparent polyimide film.

We have successfully reduced threshold voltage shifts of amorphous In–Ga–Zn–O thin‐film transistors (a‐IGZO TFTs) on transparent polyimide films against bias‐temperature stress below 100 mV, which is equivalent to those on glass substrates. This high reliability was achieved by dense IGZO thin films and annealing temperature below 300 °C. We have reduced bulk defects of IGZO thin films and interface defects between gate insulator and IGZO thin film by optimizing deposition conditions of IGZO thin films and annealing conditions. Furthermore, a 3.0‐in. flexible active‐matrix organic light‐emitting diode was demonstrated with the highly reliable a‐IGZO TFT backplane on polyimide film. The polyimide film coating process is compatible with mass‐production lines. We believe that flexible organic light‐emitting diode displays can be mass produced using a‐IGZO TFT backplane on polyimide films.

The structural and electronic properties of the Li1+xV3O8 insertion electrode, where 0 ≤ x < 0.4, have been explored by means of x-ray four-circle diffraction and through measurements of electrical resistivity, thermoelectric power, magnetization and electron paramagnetic resonance. Detailed structure refinements for x = 0.06 and 0.29 reveal the preferential and partial reduction of V ions which may give rise to low-dimensional electronic properties. The composition with x = 0 exhibits a quasi-one-dimensional polaronic transport in the localized states of band tails due to the slight deficiency of oxygen atoms. For x > 0.1 with nearly stoichiometric oxygen atoms, small polarons exist without carrier-creation energy at high temperatures, while at low temperatures the conduction may be of variable-range hopping (VRH) type. For x > 0.2, one-dimensional magnetic properties appear due to sizable exchange couplings and order–disorder effects of additional Li ions may lead to significant change of transport properties. For the intermediate composition 0 < x ≤ 0.1, strong randomness of the Li doping and the congenital oxygen deficiency cause VRH states even at high temperatures.

A large shift of the localized surface plasmon resonance (LSPR) spectrum of gold nanoparticles was attained by electrochemical oxidation of the nanoparticle surface. This oxidation occurred in the cell, which consisted of a pair of indium tin oxide (ITO) electrodes and water medium between the electrodes. On one side of the ITO electrode, the gold nanoparticles were adsorbed. With the application of a voltage of 5 V to the cell, a spectrum shift as large as 68 nm was obtained. Though the spectrum shift has already been observed by changing liquid crystal (LC) orientation surrounding gold nanoparticles, the size of the shift was not large (11 nm). That was because the variation of the effective refractive index of LC was rather small. Our large shift due to electrochemical oxidation resulted from the large refractive index of Au-O. The electrochemical oxidation was confirmed by XPS analysis of the gold nanoparticles with the LSPR spectrum shift. Other possible mechanisms of the shift such as charge localization, aggregation, and adsorption of charged materials proved to have no effect via SEM measurement and so on. This large shift of the resonance spectrum can be expected to lead to further development of spatial light modulators for next-generation optical communications and displays.

Semiconducting oxide nanoparticles are strongly influenced by surface-adsorbed molecules and tend to generate an insulating depletion layer. The interface between a noble metal and a semiconducting oxide constructs a Schottky barrier, interrupting the electron transport. In the case of a Pt catalyst supported on the semiconducting oxide Nb-doped SnO2 with a fused-aggregate network structure (Pt/Nb-SnO2) for polymer electrolyte fuel cells, the electronic conductivity increased abruptly with increasing Pt loading, going from 10–4 to 10–2 S cm–1. The Pt X-ray photoemission spectroscopy (XPS) spectra at low Pt loading amount exhibited higher binding energy than that of pristine Pt metal. The peak shift for the Pt XPS spectra was larger than that of the Pt hard X-ray photoemission spectroscopy (HAXPES) spectra. For all of the spectra, the peaks approached the binding energy of pristine Pt metal with increasing Pt loading. The Sn XPS spectral peak proved the existence of Sn metal with increasing Pt loading, and the peak intensity was larger than that for HAXPES. These spectroscopic results, together with the scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDX) spectra, proved that a PtSn alloy was deposited at the interface between Pt and Nb-SnO2 as a result of the sintering procedure under dilute hydrogen atmosphere. Both Nb spectra indicated that the oxidation state of Nb was +5 and thus that the Nb cation acts as an n-type dopant of SnO2. We conclude that the PtSn alloy at the interface between Pt and Nb-SnO2 relieved the effect of the Schottky barrier, enhanced the carrier donation from Pt to Nb-SnO2, and improved the electronic transport phenomena of Pt/Nb-SnO2.