Direct anodic oxidation of 1,5-dihydroxynaphthalene (DHN), an important derivative of naphthalene, led to the formation of high-quality semiconducting poly(1,5-dihydroxynaphthalene) (PDHN) on stainless steel sheets in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of DHN in this medium was measured to be only 0.78 V vs. SCE, which was lower than that determined in traditional acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (0.98 V vs. SCE). As-formed PDHN films showed good redox activity and stability, together with interesting electrochromic property from brown (doped) to yellow-green (dedoped). Structural characterization, including FTIR, 1H NMR, and quantum chemistry calculations, indicated that the polymerization of DHN probably occurred at C4 and C8 positions. Moreover, thermal analysis revealed that PDHN displayed better thermal stability than that synthesized by chemical method. The fluorescence spectral studies, together with the electrical tests, showed that PDHN was a good blue light-emitter (fluorescence quantum yield higher than 0.1) with an electrical conductivity of as high as 0.46 S/cm. 相似文献
A-site-deficient perovskite cathode material La0.58Sr0.4Co0.2Fe0.8O3 − δ (L58SCF) is coated on the yttria-stabilized zirconia electrolyte by screen-printing technique. Several key fabrication parameters
including selection of additives (binder and pore former), effect of coating thickness, sintering temperature and time on
the microstructure, and electrochemical performance of cathode are investigated by scanning electron microscopy and electrochemical
impedance spectroscopy. We study the microstructure and the electrochemical property of the cathode with different kinds of
additives. Results show that the cathode possesses fine microstructure, enough porosity, and ideal electrochemical property
when polyvinyl butyral serves as both binder and pore former in the cathode. The cathode with three screen-printing coats
(thickness 28 ± 7 μm, weight 6.07 ± 0.72 mg cm−2) sintering at 1,000 °C for 2 h shows lower polarization resistance of 0.183 Ω cm2 at 800 °C. Based on the optimized parameters, the polarization resistances of the L58SCF–Ce0.8Gd0.2O1.9 – δ composite cathode display the Rp values of 0.067 Ω cm2 at 800 °C, 0.106 Ω cm2 at 750 °C, 0.225 Ω cm2 at 700 °C, and 0.550 Ω cm2 at 650 °C. 相似文献
Natural inspiration : Amphiphilic polysaccharide‐block‐polypeptide copolymers were synthesized by click chemistry from dextran end‐functionalized with an alkyne group and poly(γ‐benzyl L ‐glutamate) end‐functionalized with an azide group. The ability of these copolymers to self‐assemble into small vesicles (see picture) suggests the possibility of a new generation of drug‐ and gene‐delivery systems whose structure mimics that of viruses.
In tandem : Employing a molecular dyad and a cobalt‐based electrolyte gives a threefold‐increase in open‐circuit voltage (VOC) for a p‐type NiO device (VOC=0.35 V), and a fourfold better energy conversion efficiency. Incorporating these improvements in a TiO2/NiO tandem dye‐sensitized solar cell (TDSC), results in a TDSC with a VOC=0.91 V (see figure; CB=conductance band, VB= valence band).
The title synthesized hypophosphite has the formula V(H2PO2)3. Its structure is based on VO6 octahedra and (H2PO2)− pseudo‐tetrahedra. The asymmetric unit contains two crystallographically distinct V atoms and six independent (H2PO2)− groups. The connection of the polyhedra generates [VPO6H2]6− chains extended along a, b and c, leading to the first three‐dimensional network of an anhydrous transition metal hypophosphite. 相似文献
