Full-Color-Tunable Nanophotonic Device Using Electrochromic Tungsten Trioxide Thin Film.

Color generation based on strategically designed plasmonic nanostructures is a promising approach for display applications with unprecedented high-resolution. However, it is disadvantageous in that the optical response is fixed once the structure is determined. Therefore, obtaining high modulation depth with reversible optical properties while maintaining its fixed nanostructure is a great challenge in nanophotonics. In this work, dynamic color tuning and switching using tungsten trioxide (WO3), a representative electrochromic material, are demonstrated with reflection-type and transmission-type optical devices. Thin WO3 films incorporated in simple stacked configurations undergo dynamic color change by the adjustment of their dielectric constant through the electrochromic principle. A large resonance wavelength shift up to 107 nm under an electrochemical bias of 3.2 V could be achieved by the reflection-type device. For the transmission-type device, on/off switchable color pixels with improved purity are demonstrated of which transmittance is modulated by up to 4.04:1.

Effects of solvents on the synthesis of CuInSe2 nanoparticles for thin film solar cells.

Chalcopyrite CuInSe2 (CIS) nanoparticles were synthesized in oleic acid, 1-octadecene, oleyl amine and tetraethylene glycol at temperature above 200 degrees C. Depending on the solvent used and reaction temperature, the obtained nanoparticles had different shapes, sizes, chemical compositions, and crystal and thermal properties. CIS powders synthesized in oleic acid, 1-octadecene and oleyl amine above 200 degrees C exhibited chalcopyrite structure. On the other hand, powders prepared in tetraethylene glycol contained a mixture of CIS and CuSe compounds. The CIS powder obtained in oleyl amine had a high thermal stability over 500 degrees C. CIS thin films prepared from nanoparticles were heat-treated in order to observe changes in their property. After 10 min heat-treatment at 500 degrees C, their crystal structure and chemical composition were slightly changed, and their band gap energies were ca. 1.01 eV except in the case of powders prepared in tetraethylene glycol.

1,3-Bis(6-methyl-pyridin-2-yl)-1H-imidazol-3-ium hexa-fluoro-phosphate.

In the title salt, C17H19N4 (+)·PF6 (-), the two pyridine rings of the cation are inclined to one another by 15.89 (8)°, and inclined to the imidazole ring by 65.05 (10) and 64.07 (10)°. In the crystal, the cations and anions are linked via a series of C-H⋯N and C-H⋯F hydrogen bonds, forming two-dimensional networks lying parallel to (001).

Formation of mononuclear N,O-chelate zirconium complexes by direct insertion of epoxide into tetrakis(dimethylamido)zirconium: highly promising approach for developing an ALD precursor of ZrO2 thin films.

A zirconium complex containing an N,O-chelate and alkylamide ligand has great potential for application in atomic layer deposition (ALD). However, the synthesis of this mononuclear Zr complex remains a major challenge because of the highly electrophilic nature and rich coordination of the Zr(IV) atom. Herein, a nonclassical and highly effective route for synthesizing the mononuclear N,O-chelate Zr complex was envisaged and verified using rationally designed reactions, involving the ring-opening insertion of epoxide into tetrakis(dimethylamido)zirconium(IV) (TDMAZ) at room temperature. To the best of our knowledge, very few studies in which mononuclear Zr complexes comprising alkylamide in combination with aminoalkoxide are structurally characterized. This method is extremely simple, atom economical, and easily scalable. Importantly, the produced precursor complex enables ALD of ZrO2 at a satisfactory growth rate (0.93 Å per cycle), close to that of the commercial ALD precursor CpZr(NMe2)3 (0.9 Å per cycle).