Author Affiliations
Abstract
1 Hunan Key Laboratory of Nanophotonics and Devices, School of Physics and Electronics, Central South University, Changsha 410083, China
2 Key Laboratory of Hunan Province for Statistical Learning and Intelligent Computation, School of Mathematics and Statistics, Hunan University of Technology and Business, Changsha 410205, China
Two-dimensional (2D) nonlinear optical mediums with high and tunable light modulation capability can significantly stimulate the development of ultrathin, compact, and integrated optoelectronics devices and photonic elements. 2D carbides and nitrides of transition metals (MXenes) are a new class of 2D materials with excellent intrinsic and strong light-matter interaction characteristics. However, the current understanding of their photo-physical properties and strategies for improving optical performance is insufficient. To address this issue, we rationally designed and in situ synthesized a 2D Nb2C/MoS2 heterostructure that outperforms pristine Nb2C in both linear and nonlinear optical performance. Excellent agreement between experimental and theoretical results demonstrated that the Nb2C/MoS2 inherited the preponderance of Nb2C and MoS2 in absorption at different wavelengths, resulting in the broadband enhanced optical absorption characteristics. In addition to linear optical modulation, we also achieved stronger near infrared nonlinear optical modulation, with a nonlinear absorption coefficient of Nb2C/MoS2 being more than two times that of the pristine Nb2C. These results were supported by the band alinement model which was determined by the X-ray photoelectron spectroscopy (XPS) experiment and first-principal theory calculation. The presented facile synthesis approach and robust light modulation strategy pave the way for broadband optoelectronic devices and optical modulators.
MXenes optical properties modulation in situ growth carriers transfer nonlinear optical absorption Opto-Electronic Advances
2023, 6(10): 220162
1 1.内蒙古科技大学 材料与冶金学院, 包头 014010
2 2.内蒙古科技大学 内蒙古自治区先进陶瓷材料与器件重点实验室, 包头 014010
3 3.内蒙古科技大学 轻稀土资源绿色提取与高效利用教育部重点实验室, 包头 014010
4 4.上海大学 材料科学与工程学院, 上海 200072
直接乙醇燃料电池(DEFC)具有燃料易得、绿色高效的优点, 得到了广泛的研究, 但是DEFC催化剂存在催化效率低、稳定性差的问题, 制约了其快速发展。本研究采用液相水热合成法, 以聚乙烯吡咯烷酮(PVP k-25)为分散剂和还原剂、甘氨酸为表面控制剂和共还原剂, 通过调控Pt-Co金属前驱体的摩尔比, 一步制备了XC-72R炭黑负载的Pt1Cox/C高指数晶面纳米催化剂, 实现了催化剂晶粒在碳载体上的原位生长。Pt1Co1/3/C纳米催化剂暴露的高指数晶面主要包括(410)、(510)和(610)晶面。在晶体生长过程中, Pt1Co1/3/C纳米催化剂晶粒由“类球体”转变立方块, 最终得到具有高指数晶面取向的内凹形貌。Pt1Co1/3/C高指数晶面纳米催化剂的电催化活性最高, 其电化学活性表面积为18.46 m2/g, 对乙醇氧化峰电流密度为48.70 mA/cm2, 稳态电流密度为8.29 mA/cm2, CO氧化峰的电位为0.610 V。这说明具有高指数晶面的催化剂表面存在的台阶、扭结等缺陷原子, 可增加活性位点, 进而显示出优异的电催化性能。本研究可为高指数晶面催化剂材料的开发及工业化应用提供理论依据。
水热法 Pt-Co催化剂 高指数晶面 原位生长 直接乙醇燃料电池 hydrothermal method Pt-Co catalyst high index crystal plane in-situ growth direct ethanol fuel cell
1 大连交通大学材料科学与工程学院，大连 116028
2 清华大学，新型陶瓷与精细工艺国家重点实验室，北京 100084
本文利用简单、高效的浆料直接发泡法制备气孔率高达96%的Al2O3/Si泡沫陶瓷，并选用简便、易行的焦炭埋烧工艺在Al2O3/Si泡沫陶瓷坯体中生长出大量SiC纳米线。通过控制烧结温度来观察分析SiC纳米线的生长形貌变化。采用扫描电子显微镜(SEM)、X射线衍射仪、BET比表面积测试仪、电子万能试验机等对泡沫陶瓷的微观结构、物相组成、比表面积、气孔率、抗压强度、热导率进行分析与表征。结果表明，1 450 ℃烧结时得到的SiC纳米线最多，纳米线在泡沫陶瓷孔壁交织缠绕。同时观察到SiC纳米线的存在改变了氧化铝泡沫陶瓷固有的脆性断裂模式，SiC纳米线可有效促进泡沫陶瓷在压缩过程中的裂纹偏转。本实验制备了一种新型的纳米线缠绕在孔壁上的三维网络结构的泡沫陶瓷，为在泡沫陶瓷内部原位生长SiC纳米线提供了新的方法，更好地拓展了泡沫陶瓷在环境过滤、催化剂载体等领域中的应用。
氧化铝泡沫陶瓷 SiC纳米线 埋烧 直接发泡法 烧结温度 纳米线原位生长 三维网络结构 alumina foam ceramics SiC nanowire burying sintering direct foaming method sintering temperature in-situ growth of nanowire three-dimensional network structure
Author Affiliations
Abstract
1 State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
2 Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
We present a facile and effective method for fabrication of the localized surface plasmon resonance (LSPR) optical fiber sensor assisted by two polydopamine (PDA) layers with enhanced plasmonic sensing performance. The first PDA layer was self-polymerized onto the bare optical fiber to provide the catechol groups for the reduction from Ag+ to Ago through chelating and redox activity. As the reduction of Ag+ proceeds, Ag nanoparticles (NPs) were grown in-situ on the PDA layer with uniform distribution. The second PDA layer was applied to prevent Ag NPs from oxidating and achieve an improvement of LSPR signal. The PDA/Ag/PDA-based optical fiber sensor has an enhanced LSPR sensitivity of 961 nm/RIU and excellent oxidation resistance. The stable PDA/Ag/PDA-based LSPR sensor with high optical performance is very promising for future application in optical sensing field.
LSPR optical fiber polydopamine in-situ growth silver nanoparticles Photonic Sensors
2020, 10(2): 97
福州大学 物理与信息工程学院, 平板显示技术国家地方联合工程实验室, 福建 福州 350108
近年来, 金属卤化物钙钛矿以其光吸收系数高、色纯度高、色域广、发光波长连续可调、光致发光量子产率高、载流子扩散长度大和成分稳定不易分解等优点, 成为光电子应用领域极具潜力的新材料, 其在太阳能电池、发光二极管、忆阻器、激光器、光电探测器和防伪标签等方面均有出色的表现, 并且可通过简单的全溶液法制备, 为印刷工艺的结合、大尺寸生产和产业化提供了可能。实验采用一步溶液法制备了原位生长的溴化铅铯钙钛矿薄膜, 其在(100)晶面有择优取向, 且相应的晶面间距小于PDF标准卡片值。通过增大前驱液的浓度, 使样品的形貌结构产生差异, 薄膜的连续性和致密性随之提高, 晶粒得到细化, 在375 nm激发光下的光致发光(PL)强度得到约5倍的提升, 且PL峰位蓝移6 nm, 同时该过程导致的晶格畸变使其PL光谱半高宽(FWHM)增大超过2 nm。
钙钛矿 原位生长 结构特性 发光特性 前驱液浓度 perovskite in situ growth structure characteristics luminescence characteristics precursor concentration
1 中国科学院 金属研究所, 沈阳材料科学国家研究中心, 沈阳 110016
2 中国科学技术大学 材料科学与工程学院, 合肥 230026
钙钛矿相SrTiO3在太阳能电池、光催化、燃料电池, 超导等领域均有广泛应用, 这些应用均与其晶体质量、形貌、暴露晶面和光学吸收等特性息息相关。本文通过微弧氧化-水热两步法原位制备了两种典型形貌的SrTiO3纳米晶。结果表明, 随着微弧氧化电解液锶源浓度的降低, SrTiO3形貌从立方块状转变为超薄片状。进一步分析表明, 所得的SrTiO3立方块和Sr1-δTiO3纳米片均为结晶质量良好的单晶体, 通过分析两种形貌样品的紫外-可见漫反射光谱, 发现Sr1-δTiO3纳米片相对于SrTiO3立方块, 具有明显的尺寸效应诱导的光学吸收蓝移特性。最后, 本研究提出了SrTiO3的原位生长及形貌演变机制。
SrTiO3 in-situ growth plasma electrolytic oxidation morphology tuning optical property 钛酸锶 原位生长 微弧氧化法 形貌调控 光学性能
华中理工大学激光技术国家实验室, 武汉 430074
采用低压氧气放电辅助的激光淀积方法,原位外延生长出零电阻温度91K,临界电流密度105A/cm2的Y-Ba-Cu-O高温超导薄膜。扫描电镜和X光衍射分析结果表明,薄膜中超导相晶粒的生长具有c轴垂直于表面的择优取向。
放电辅助 激光淀积 原位生长 超导薄膜
