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11.
采用氧化还原水热法合成二氧化锰。研究了在氧化剂及反应温度等条件相同的情况下,不同反应时间和还原剂对二氧化锰晶型及电化学性能的影响。通过对产物进行XRD分析发现,还原剂为MnSO4时,仅生成单相α-MnO2;而在Mn(NO3)2和MnCl2溶液中,随着反应时间由2~24 h增加到48 h,产物由含有γ-MnO2的α-MnO2转变为单相β-MnO2。对反应时间为12 h生成的二氧化锰进行了循环充放电测试。结果显示,在Mn(NO3)2和MnCl2溶液中生成的含有γ-MnO2的α-MnO2,其初次放电容量分别为203和186.3 mA.h/g,均比在MnSO4溶液中生成的单相α-MnO2的容量140 mA.h/g高;7次循环充放电后,在Mn(NO3)2,MnCl2和MnSO4溶液中生成的MnO2的容量分别保持在初次放电容量的51%,54%和49%。 相似文献
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综述了对自组装量子点形态和生长过程所做的探讨和研究。介绍了关于量子点成核和形态的热力学理论、量子点生长过程的计算机模拟及Ge/Si(001)和InAs/GaAs(001)量子点生长和形态的实验观察。鉴于InAs/GaAs(001)体系的复杂性,把对InAs量子点的观察和研究分为"微观"和"宏观"两种。微观研究对象包括量子点原子尺度上的结构、量子点表面小晶面的晶体学的精确取向等,这些性质可能受热运动的影响比较大,在一定程度上是随机的,它们代表了量子点生长行为的复杂性;宏观研究的对象是指量子点密度、纳米尺度形态等大量粒子统计意义上的集体行为,这些性质和行为可能更具有实际意义。因此作者认为,目前研究量子点生长和形态更为有效的方法应该是探寻以量子点宏观行为所表征的简单性。重点介绍中科院半导体所半导体材料重点实验室最近所做的对InAs/GaAs(001)量子点生长过程的实验观察。结果表明,在一般生长条件下(富As,500℃,0.1ML/s),InAs量子点成核和生长应该都是连续的,没有经历被普遍认为的不连续(一级)相变。按照作者的观察,把InAs量子点成核看作是连续(二级)相变更为贴切。 相似文献
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相对于Ⅱ-Ⅵ族二元化合物,三元合金在调节带隙宽度和晶格常数上的灵活性使其应用前景更加广阔,并有希望解决Ⅱ-Ⅵ族材料普遍存在的单极性掺杂难题而成为未来新型光电器件发展的一个重要方向.文章着重介绍了分子束外延(MBE)技术生长ZnSeTe、CdZnTe、CdSeTe等Ⅱ-Ⅵ族三元合金单晶薄膜的研究现状,分析了MBE生长三元合金时需要考虑的问题,介绍了Ⅱ-Ⅵ族半导体材料n/p型掺杂的常用元素和掺杂方式,讨论了限制Ⅱ-Ⅵ族材料有效掺杂的物理机制和三元合金在掺杂方面的研究动态,并对三元合金薄膜的发展前景进行了展望. 相似文献
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Qiang Chen Hang Li Xuan Lou Jianli Zhang Guangya Hou Jun Lu Yiping Tang 《Advanced functional materials》2023,33(17):2214920
Aqueous ammonium ion hybrid supercapacitor (A-HSC) combines the charge storage mechanisms of surface adsorption and bulk intercalation, making it a low-cost, safe, and sustainable energy storage candidate. However, its development is hindered by the low capacity and unclear charge storage fundamentals. Here, the strategy of phosphate ion-assisted surface functionalization is used to increase the ammonium ion storage capacity of an α-MoO3 electrode. Moreover, the understanding of charge storage mechanisms via structural characterization, electrochemical analysis, and theoretical calculation is advanced. It is shown that NH4+ intercalation into layered α-MoO3 is not dominant in the A-HSC system; rather, the charge storage mainly depends on the adsorption energy of surface “O” to NH4+. It is further revealed that the hydrogen bond chemistry of the coordination between “O” of surface phosphate ion and NH4+ is the reason for the capacity increase of MoO3. This study not only advances the basic understanding of rechargeable aqueous A-HSC but also demonstrates the promising future of surface engineering strategies for energy storage devices. 相似文献
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Xiong Luo Lei Zhang Yiping Luo Zhuyun Cai Hua Zeng Tianlong Wang Zhiqing Liu Yixing Chen Xuexin Sheng Aquino Ernesto da Graça Mandlate Zifei Zhou Feng Chen Longpo Zheng 《Advanced functional materials》2023,33(26):2214036
The treatment of diabetic wound remains a big clinical challenge. Hydrogel that can provide physical barrier and humidity displays amazing potentials for managing the diabetic wounds healing. Herein, a new charge-driven self-assembled microsphere hydrogel scaffold (SMHS) is reported based on an electric charge interaction, by combining use of black phosphorus (BP)-contained chitosan methacryloyl (CS) microspheres with positive charge and basic fibroblast growth factor-contained hyaluronic acid methacryloyl (HA) microspheres with negative charge. The weak charge attraction among microspheres gives the SMHS the injectable characteristic. Due to the existence of BP, near-infrared (NIR) irradiation has obvious effects on the degradation and drug release behaviors of SMHS. Significantly, SMHS that combines the short-term physical (photothermal) intervention and long-term chemical (drug release) intervention may be promising in spatio-temporal regulation of regenerative microenvironment. SMHS with NIR irradiation (SMHS+NIR) can promote cell proliferation, cell migration, angiogenesis and macrophage polarization. Moreover, in diabetic rat skin wounds, SMHS+NIR significantly accelerates the wound healing process by simultaneously inhibiting the inflammatory response, promoting angiogenesis and tissues remodeling. The outcome of this research not only provides a biomaterial for diabetic wounds healing, but also demonstrates a new strategy for designing novel hydrogel-based biomaterials which have the free editing and combination functions. 相似文献
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Wang Xiaofeng Zeng Yiping Wang Baoqiang Zhu Zhanping Du Xiaoqing Li Min and Chang Benkang 《半导体学报》2005,26(9):1692-1698
The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for negative-electron-affinity GaAs photocathodes is investigated.Two GaAs samples with the monolayer structure and the multilayer structure are grown by molecular beam epitaxy.The former has a constant Be concentration of 1e19cm-3,while the latter includes four layers with Be doping concentrations of 1e19,7e18,4e18,and 1e18cm-3 from the bottom to the surface.Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system.The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the multilayer structure enhanced by at least 50% as compared to that of the monolayer structure.This attributes to the improvement in the crystal quality and the increase in the surface escape probability.Different stress situations are observed on GaAs samples with monolayer structure and multilayer structure,respectively. 相似文献
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Haijun Tan Chunyue Pan Gang Wang Yingying Wu Yiping Zhang Yingping Zou Guipeng Yu Min Zhang 《Organic Electronics》2013,14(11):2795-2801
A series of organic dyes (POZ-2, POZ-3, POZ-4 and POZ-5) involving phenoxazine were synthesized as sensitizers for application in dye-sensitized solar cells (DSSCs). For comparison, three different electron donors namely 10-phenyl-10H-phe-nothiazine, 10-phenyl-10H-phenoxazine and triphenylamine were separately appended onto the 7-position of the model dye (POZ-2). The obtained four dyes exhibit considerably high values of conversion efficiencies of 6.6%, 7.8%, 7.1% and 6.4%, respectively, under the simulated AM1.5G conditions. The geometries of the dyes were optimized to gain insight into the molecular structure and electron distribution, and then the charge extraction and transient photovoltage decay measurements were further performed to understand the influence of electron donors on the photovoltaic behaviors. 相似文献