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Cheng X.H.,Anhui University | Xu H.F.,Anhui University | Wang Z.Z.,Anhui University | Zhu K.R.,Anhui University | And 3 more authors.
Materials Research Bulletin | Year: 2013

Pure phase VO2(A) nanorods were synthesized via the reduction of V2O5 by oxalic acid during the hydrothermal treatment. Two sets of samples were prepared by varying both system temperature and reaction time under a filling ratio of 0.40 for observing the formation and evolution of VO2(A) nanorods. Structures were characterized by X-ray diffraction, scanning and transmission electron microscopies, respectively. It was found that VO2(B) was firstly formed and then transformed into VO2(A) as the increasing system temperature or extending reaction time. An assembling and following crystal adjustment was proposed for explanation the formation process of VO2(A) from VO2(B). For VO2(A) nanorods, the phase transition temperature of 169.7 C was higher than that of the VO2(A) bulk, it might be ascribed to the lower crystallinity or nonstoichiometry in VO2(A) nanorods. VO 2 nanostructures with controllable phases and properties should find their promising applications in a single VO2 nanodevice. © 2013 Elsevier Ltd. All rights reserved. Source


Shi W.,Anhui University | He H.,Anhui University | Zhang X.,Anhui University | Feng A.L.,Anhui University | And 2 more authors.
Materials Research Bulletin | Year: 2012

A co-precipitation reaction was used to prepare nanocrystal Gd 6WO 12:Eu 3+ and Gd 2WO 6:Eu 3+ red emitting phosphor powders with different Eu 3+ doping levels. It is found that under the same preparation conditions, different doping level leads to different crystal structures; Gd 6WO 12-like with a tetragonal lattice structure tends to be synthesized at low doping level (10-40 mol%) yet Gd 2WO 6-like with a monoclinic lattice structure easily to grow at high doping level (60-80 mol%). The strong red emission of 5D 0 → 7F 2 transitions at 620 nm was observed for all powders under either near ultraviolet or blue light excited and the most intense emission was obtained at the concentration of 40 mol%. This kind of powders might find their promising application to compensate the white LEDs for the lack of red light component and to improve rendering index. © 2012 Elsevier Ltd. All rights reserved. Source


Yang X.,Anhui University | Yu X.,Anhui University | Li G.,Anhui University | Li G.,Anhui Key Laboratory of Information Materials and Devices
Journal of Materials Science: Materials in Electronics | Year: 2016

CeO2 nanorods have been successfully synthesized by a facile one-step hydrothermal synthesis route only using Na3PO4·6H2O as mineralizer without any surfactant or template. XRD, SEM, TEM, XPS, Raman scattering, Photoluminescence spectra and UV–vis were employed to characterize the samples. The results showed that all the samples have a fluorite cubic structure and there are Ce3+ ions and oxygen vacancies in the surface of non-doped CeO2 nanorods. The visible luminescence exhibits similar emission peaks of room temperature photoluminescence and the emission intensity increases with the increase of concentration of Nd ions and then decrease. The band gap decreases with the increase of dopant, Nd3+ ions result in an effective red shifting of the band gap. © 2016 Springer Science+Business Media New York Source


Shi W.,Anhui University | Feng A.,Anhui University | Tang H.,Anhui University | Ding Z.,Anhui University | And 4 more authors.
Optical Materials | Year: 2013

A co-precipitation method was employed to prepare Eu3+-doped gadolinium tungstate and Y3Al5O12:Ce fluorescent powders. Eu3+-doped gadolinium tungstate phosphors can be effectively excited both by ultraviolet light at 395 nm and blue light at 465 nm and emit remarkably intense red emission at 613 nm with near line spectrum. Ce3+-doped YAG can also efficiently absorb this blue light and produce a broad band of luminescence centering at 540 nm. The red fluorescent powder and yellow fluorescent phosphor were then mixed together at different weight ratios. It is found that the emission spectra of the blended phosphors excited with blue light at 465 nm is the superposition of the two phosphors, which means that the mixture's emission can be tuned by controlling the weight ratios. These results demonstrated the possibility of using the blended phosphors to increase the color-rendering properties of white LEDs. © 2012 Elsevier B.V. All rights reserved. Source


Zhong Y.,Anhui University | Chen P.,Anhui University | Yang B.,Anhui University | Zuo X.,Anhui University | And 4 more authors.
Applied Physics Letters | Year: 2015

In this work, the perovskite-type La0.67Sr0.33MnO3 (LSMO) oxide with perfect crystallinity was synthesized via sol-gel method and used as low-cost platinum-free counter electrodes (CEs) for dye-sensitized solar cell (DSSCs). The electrochemical characterizations indicate that LSMO electrode possesses excellent electrocatalytic activity for the I3- reduction and excellent electrochemical stability in I-/I3- electrolyte system. The DSSC based on this counter electrode achieves an energy conversion efficiency (η) of 6.62%, which approaches 92.6% of the level obtained by using Pt as CE (η=7.15%). Theperovskite-type oxide is low-cost and can be massively produced via sol-gel method which is superior to the solvothermal method. This work makes an attempt to develop potential counter electrode materials in perovskite-type oxides, which can help reduce the cost of DSSCs and thereby encourage their fundamental research and commercial applications. © 2015 AIP Publishing LLC. Source

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