The N-C coupling of ligating NO with 2-vinylpyridines, affording nitrosovinyl complexes, was found. This is of significance since the reaction process involves a C-H activation of the vinyl moiety and subsequent C-N bond formation. Furthermore, we show that the resulting nitrosovinyl complexes are chemically versatile and potentially valuable species. Protonation of the resulting nitrosovinyl complexes in refluxing alcohol afforded the alcohol-incorporated complexes, as well as the ketoimine species. It is interesting to note that a proton-induced reaction with PPh3 trapped their intermediates, leading to the explication of these reaction mechanisms.

Thin-film light-emitting diodes (LEDs) containing solution-processed ZnO nanocrystals (NCs) were prepared as printed electronics. The electroluminescent (EL) properties of thin-film LEDs were investigated along with the structural and photoluminescence (PL) properties of the ZnO NCs. Scanning electron microscope and x-ray diffraction studies revealed that the crystal sizes D were ranged from 5–11 nm, and can be controlled by varying growth time tG in the Zn2+/OH− solution at 40 °C. The time evolution of D was analyzed using Lifshitz–Slyozov–Wagner theory, showing that growth is limited by diffusion. The results of PL studies indicated that increases in the peak energies in the ultraviolet (UV) region could be attributed to the quantum-size effects on the exciton emission in the NCs with a small D, the ZnO surfaces became sufficiently passivated as D increases. Printed layers containing well-passivated ZnO NCs with different D of 8–11 nm were used as emission layers in thin-film LEDs together with pentacene hole transport layers. The current-voltage characteristics were analyzed using the trapped-charge-limited current mechanism. EL spectral measurements revealed the presence of weak UV emission that increased slightly as D decreased.

ZnO is an excellent material candidate for ultraviolet (UV)‐light emitting devices based on its exciton emission. We have applied solution‐processed ZnO NCs to printed electroluminescence (EL) devices as their emission layers (EMLs) to develop a novel flexible lightweight, and flat‐panel UV‐light source. In this article, first, the structural properties of ZnO NCs fabricated from a solution route are presented together with the results of photoluminescence (PL). We address to suppression of the defect‐related green‐band PL from ZnO NCs by controlling the crystal size. Next, we describe device properties of the printed EL devices. Specifically, we present the impact on the use of pentaceneon the device properties; pentacene acts as the hole‐transport layer, resulting in the exciton emissions in EL. In addition, it passivates the rear surface of ZnO NC EML, which is effective in suppressing the green‐band EL. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Top-emission light-emitting diodes containing nanoparticles (NanoLEDs) were prepared for flexible electronics applications. Transmission electron microscopy images revealed that solution-processed ZnO nanocrystals (NCs) embedded in a printed emission layer were nearly monodisperse with a crystal size of about 10 nm. To improve the UV electroluminescent emission of ZnO excitons and suppress visible emission from surface defects of the NCs, the low-power deposition of indium tin oxide (ITO) top electrodes was examined together with the deposition of a MoO3 layer before ITO. Finally, conversion from UV to green light via a phosphor is demonstrated, revealing the color tunability of the NanoLEDs.