Sb_2S_3纳米线的合成以及其在光降解和光电传感方面的应用

通过低温溶剂热法合成出氯化锑(Sb_2S_3)纳米线。通过XRD、SEM、TEM、SAED等微纳测试技术表征合成的Sb_2S_3样品,显示出合成的样品是单晶正交相的Sb_2S_3纳米线。此外,利用XPS分析技术研究了Sb_2S_3的电子价态,并通过紫外-可见光反射谱来计算Sb_2S_3纳米线的带隙大约为1.55eV。为了开拓Sb_2S_3的应用,研究了Sb_2S_3在可见光照射下催化降解罗丹明B(RhB),证明了Sb_2S_3纳米线具有良好的光催化降解效果。并且基于Sb_2S_3纳米线制作了一个光电器件,在间歇的光照下,该器件表现出了明显的光开关效应,响应时间和恢复时间都很短,低于280ms。这些研究成果表明所合成的Sb_2S_3纳米线在光催化、光电传感等领域具有潜在的应用价值。     

硫化铋纳米花的可控制备

通过水热法以Bi(NO_3)_3·5H_2O为铋源、CH_4N_2S为硫源、尿素为矿化剂,在丙三醇与水的混合溶剂中制备不同尺寸的Bi_2S_3纳米花。运用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、紫外-可见-近红外分光光度计(UV-Vis-NIR)、荧光分光光度计(PL)等检测手段对样品进行表征。结果表明,合成的Bi_2S_3为正交相纳米晶结构,Bi2S3纳米花的生长是固相-液相-固相转化过程,样品形貌和尺寸受到反应物摩尔比、溶剂种类、合成温度、合成时间等因素影响。通过控制不同的条件可得到形貌均一的纳米花,并对Bi_2S_3纳米花的光学性能及生长过程进行了初步讨论。     

水热合成BiCl_3/Bi_2S_3复合材料的热电性能（英文）

采用水热合成法制备了由纳米棒组成的微米级球形Bi_2S_3颗粒,然后通过放电等离子烧结技术(SPS)将不同摩尔比例的BiCl_3/Bi_2S_3复合粉末制备成块体。加入适量的BiCl_3不仅提高了Bi_2S_3样品的导电率,而且降低了其热导率。Bi_2S_3复合0.5mol%BiCl_3的样品在762 K电导率最大,达到45.1 S·cm~(-1),远高于此温度下纯Bi_2S_3样品的电导率(12.9 S·cm~(-1))。Bi_2S_3复合0.25mol%BiCl_3的样品在762 K时热导率最低,为0.31 W·m~(-1)·K~(-1),低于同一温度下纯Bi_2S_3的0.47 W·m~(-1)·K~(-1)。在762 K下,Bi_2S_3复合0.25mol%BiCl_3的样品获得最大ZT值(0.63),比纯Bi_2S_3样品(0.22)提高了大约2倍。     

Bi2S3@BiOBr的原位合成及其可见光催化性能

采用溶剂热法合成BiOBr空心微球,并利用简单的离子交换原位生成Bi_2S_3,得到类核-壳结构的Bi_2S_3@BiOBr复合光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(FE-SEM)和紫外-可见漫反射光谱(UV-Vis DRS)等手段对催化剂进行表征,并对其进行光电化学性能测试。实验表明,BiOBr与Bi_2S_3形成的异质结促进了光生载流子的转移和分离。Bi_2S_3@BiOBr在可见光作用下可以有效降解甲基橙,当Bi_2S_3的摩尔分数为8%时,样品具有最好的光催化性能。·O_2~-和h~+是Bi_2S_3@BiOBr光催化降解甲基橙的主要活性物种。     

Na_(1.88)Bi_(1.88)S_4和Na_(1.36)Ca_(1.28)Bi_(1.36)S_4单晶制备与结构及其光学性能表征（英文）

采用碘化钠为助熔剂,通过固相反应法制备了两种晶体质量较好的Na_(1.88)Bi_(1.88)S_4和Na_(1.36)Ca_(1.28)Bi_(1.36)S_4单晶。测试结果表明,它们属于氯化钠结构,面心立方,空间群为Fm-3m。形貌表征和物性测试结果表明,在碘化钠的作用下,化合物Na_(1.88)Bi_(1.88)S_4和Na_(1.36)Ca_(1.28)Bi_(1.36)S_4呈现双锥状形貌,沿(111)晶面择优取向生长,带隙分别为1.29和1.45 eV。通过光电器件性能测试,发现两种化合物均表现出良好的光电响应特性,说明它们可以作为一类潜在的、性能优良的光电开关材料。     

零维/二维Bi_2S_3/g-C_3N_4异质结的原位构建及光催化性能

采用简单的一步溶剂热法,以硝酸铋为铋源,硫代硫酸钠为硫源,将Bi_2S_3纳米粒子原位修饰在g-C_3N_4纳米片上,成功制备了零维/二维Bi_2S_3/g-C_3N_4异质结。利用XRD、SEM、TEM、UV-Vis、荧光光谱以及电化学分析方法等手段对所制备的光催化材料进行了表征。在可见光照射下,以罗丹明B(RhB)为模型污染物,研究其光催化降解效率。结果表明,Bi_2S_3以纳米颗粒的形式分散于g-C_3N_4纳米片上,形成了零维/二维异质结结构,拓宽了g-C_3N_4在可见光区的吸收,降低了电子-空穴对的复合概率;与纯g-C_3N_4相比,Bi_2S_3/g-C_3N_4异质结表现出更高的光催化效率。同时,Bi_2S_3/g-C_3N_4催化剂具有良好的光催化稳定性,经过5次循环后其光催化活性基本稳定。     

水热法合成Ag_2S/Bi_2S_3复合材料及其热电性能研究

采用水热合成法结合放电等离子烧结技术制备了Ag_2S/Bi_2S_3块体热电复合材料。采用XRD、SEM和TEM对合成粉末材料的相组成和微观形貌进行分析,闪光法和塞贝克系数/电阻测量系统测试复合块材的热电性能,系统地研究了Ag_2S的含量对Ag_2S/Bi_2S_3复合材料热电性能的影响。实验结果表明,水热法成功地合成了具有球形结构的Ag_2S/Bi_2S_3复合粉末;块体样品的塞贝克系数都为负,说明样品为n型半导体;适量的Ag_2S复合Bi_2S_3不仅有效地降低了材料的热导率,同时也提高了电导率;当Bi_2S_3与3%的Ag_2S复合时样品的热电优值(ZT值)最大,其在724K时的ZT值为0.23,为纯Bi_2S_3样品在该温度ZT值的2.3倍。     

Bi_2S_3-BiOCl/煤矸石复合光催化剂的制备及光催化性能

以表面改性煤矸石粉、Bi(NO_3)_3·5H_2O和NH_4Cl为原料,采用超声化学法制备了BiOCl/煤矸石前驱体;并通过BiOCl/煤矸石前驱体和硫代乙酰胺(TAA)的阴离子交换反应,原位制备了Bi_2S_3-BiOCl/煤矸石复合光催化剂。利用XRD和SEM对Bi_2S_3-BiOCl/煤矸石复合光催化材料的结构及表面形貌进行了表征,并以可见光为光源,甲基橙为目标降解物,对其光催化活性进行了研究。结果表明:在可见光辐照下,Bi_2S_3-BiOCl/煤矸石复合光催化剂表现出较高的光催化降解能力,这是由于Bi_2S_3与BiOCl复合后形成的异质结促进了光生电子和光生空穴的分离,抑制了它们的复合。     

Bi_2O_3-ZnO复合材料的制备及其性能

以Bi_2O_3纳米棒为前驱体,通过溶剂热法合成了一维Bi_2O_3-ZnO复合材料光催化剂。XRD物相分析,复合材料光催化剂为六方纤锌矿结构的ZnO和四角形结构的Bi_2O_3;SEM形貌观察,复合材料光催化剂为棒状Bi_2O_3,平均直径为(450±50)nm,长度为(5±1)μm,以及少量的ZnO纳米粒/片生长在Bi_2O_3的表面。在可见光照射下,分别以纯的Bi_2O_3、ZnO和Bi_2O_3-ZnO为光催化剂,通过降解染料亚甲基蓝(MB)和苯酚进行光催化性能研究。     

混合维度WS2/WSe2/Si单极势垒异质结构用于高性能光电探测(英文)

单极势垒异质结构可以选择性地降低暗电流,但不影响光电流,是一种构建高性能光电探测器的有效策略.特别地,具有可调谐能带结构和自钝化表面的二维(2D)材料不仅能满足能带匹配要求,而且避免了界面缺陷和晶格失配,有助于设计单极势垒异质结构.这里,我们展示了一种混合维度WS₂/WSe₂/p-Si单极势垒异质结光电探测器.其中,2D WS₂充当光子吸收体,原子级厚度的WSe₂充当单极势垒,3D p-Si充当光生载流子收集器.插入的WSe₂不仅减轻了有害的衬底效应,而且形成了高导带势垒,可以过滤掉若干暗电流分量,同时不影响光电流.在隧穿效应和载流子倍增效应的驱动下,该WS₂/WSe₂/p-Si器件表现出高于10⁵的高开/关比、2.39×10¹² Jones的高探测度和8.47/7.98毫秒的快速上升/衰减时间.这些优点显著优于传统的WS₂/p-Si器件,为设计高性能的光电器件开辟了一...     

Sensitive solution-processed Bi2S3 nanocrystalline photodetectors

Solution-processed nanocrystal optoelectronic devices offer large-area coverage, low cost, and compatibility with a wide range of substrates. Recently, photodetectors and photovoltaics based on spin-coated nanoparticle films have shown tremendous progress in performance. However, high-performance devices reported to date have employed either Pb or Cd, raising concerns regarding environmental impact and regulatory acceptance. Herein we report a high-performance solution-processed photodetector based instead on Bi2S3 nanocrystals. The devices exhibit photoconductive gain on the order of 10 combined with temporal response on the 10 ms time scale. The resultant solution-processed Bi2S3 nanorod photoconductive photodetectors are of interest in visible and near-infrared (NIR) wavelength applications requiring video-frame-rate temporal response.     

Single-crystalline Bi(2)S(3) nanowire network film and its optical switches

A single-crystalline bismuth sulfide (Bi(2)S(3)) nanowire network film at a centimeter scale is fabricated by the facile hydrothermal method. The Bi(2)S(3) film is easily tape-transferred onto a soft plastic substrate, and is further used to fabricate optical switches by screen-printing an Ag?electrode array on its top. Our studies demonstrate that the Bi(2)S(3) nanowire network has a pronounced increase in conductance upon exposure to visible light, and possesses a very fast response time of about 2?ms. This work provides a simple and economic method to fabricate a high performance optical switch array and could offer great potential for a low cost, mass-manufacturing process.     

基于p-Se/Al2O3/n-ZnO纳米棒阵列异质结的自驱动紫外-可见光探测器

自驱动光探测器能够在无外加偏压的情况下将光信号转化为电信号, 在工业和军事领域有着广泛的应用。本研究报道了p型Se薄膜和n型ZnO纳米棒阵列异质结的可控合成以及它们作为自驱动紫外-可见光探测器的应用。由于在ZnO和Se的界面处形成的内建电场将光生电子-空穴对分离, 促使它们向相反方向传输, 最终被电极收集, 在0偏压下获得了较高的光电流(435 pA), 从而实现无线的自驱动光电探测。并且, 在Se和ZnO界面处沉积的Al₂O₃层有效降低了暗电流。最终, 此器件在500 nm的单色光下显示了高响应率55 μA·W ^-1和大比探测率5×10 ¹⁰Jones, 并表现出了极快的响应速度(上升时间0.9 ms, 衰减时间0.3 ms)。     

Morphology controlled synthesis of spherical Bi2S3 flowers

The spherical Bi2S3 flowers have been fabricated by a facile environmentally friendly hydrothermal method. It was found that the flowers are composed of pure orthorhombic phase Bi2S3, the nanorods (nanowires) composed of the flowers grow radically from a center toward all directions to form a spherical structure, and the nanowires are single-crystalline and grow along the [001] direction. The reaction time, reaction temperature and thiourea play key roles for the formation of the flowers. The morphology of the Bi2S3 flowers (e.g., honeycombs, porous nanorods, nanorods, and nanowires) can be controlled simply by controlling the reaction time without varying experimental parameters or addition of other surfactant. The formation mechanism of Bi2S3 flowers is self-assembly and the intrinsic splitting character of the Bi2S3 structure. The spherical Bi2S3 flowers could be found potential applications in optical, catalysts and sensor devices.     

Solar-blind ultraviolet photodetector based on Ti-doped Ga2O3/Si p–n heterojunction

A solar-blind ultraviolet photodetector based on Ti-doped Ga₂O₃/Si p–n heterojunction is demonstrated for the first time. It is found that the heterojunction quality forming between Ga₂O₃ and Si becomes better after Ti incorporation in Ga₂O₃. The current–voltage and temporal response measurements show that the detector based on Ti-doped Ga₂O₃/Si p–n heterojunction has a responsivity of 0.382 A/W and a fast rise time of 73 ms as well, which are much better than those undoped Ga₂O₃/Si p–n heterojunction analogues.

     

用于生物荧光检测的CMOS光电探测器设计

在标准CMOS 工艺参数基础上,设计了三种(P /Nwell 型,Nwell/Psub 型和N /Psub 型)光电探测器.通过对光电转换原理的详细分析以及数学模型的建立,理论上比较了三种探测器在灵敏度,暗电流,峰值响应波长等特性的差异,阐述了掺杂浓度,结深等工艺参数对器件性能的影响,并且采用SMIC0.18 μ m CMOS 工艺进行流片验证.测试结果表明,P /Nwell 型结构最大灵敏度为0.08 A/W ,峰值响应波长460 nm ,暗电流55nA/cm 2 ;Nwell/Psub型结构最大灵敏度为0.35 A/W ,峰值响应波长580 nm ,暗电流64 nA/cm 2 ;N /Psub 型结构最大灵敏度为0.29 A/W ,峰值响应波长580 nm ,暗电流600 nA/cm 2 .测试结果表明,所设计的光电探测器性能与理论分析基本一致,在灵敏度,响应波长方面性能突出.     

Ultrathin Single‐Crystalline CdTe Nanosheets Realized via Van der Waals Epitaxy

Due to the novel physical properties, high flexibility, and strong compatibility with Si‐based electronic techniques, 2D nonlayered structures have become one of the hottest topics. However, the realization of 2D structures from nonlayered crystals is still a critical challenge, which requires breaking the bulk crystal symmetry and guaranteeing the highly anisotropic crystal growth. CdTe owns a typical wurtzite crystal structure, which hinders the 2D anisotropic growth of hexagonal‐symmetry CdTe. Here, for the first time, the 2D anisotropic growth of ultrathin nonlayered CdTe as thin as 4.8 nm via an effective van der Waals epitaxy method is demonstrated. The anisotropic ratio exceeds 10³. Highly crystalline nanosheets with uniform thickness and large lateral dimensions are obtained. The in situ fabricated ultrathin 2D CdTe photodetector shows ultralow dark current (≈100 fA), as well as high detectivity, stable photoswitching, and fast photoresponse speed (τ_rising = 18.4 ms, τ_decay = 14.7 ms). Besides, benefitting from its 2D planar geometry, CdTe nanosheet exhibits high compatibility with flexible substrates and traditional microfabrication techniques, indicating its significant potential in the applications of flexible electronic and optoelectronic devices.     

Solvothermal synthesis and conductive properties of nanorod-constructed Al-doped ZnO microflowers

Nanorod-constructed Al-doped ZnO (AZO) microflowers were for the first time synthesized by a facile solvothermal route. The synthesis involves a low-cost, template-free, non-seed and catalyst-free solution process to relatively high conductive AZO crystalline. In this process, the morphology of the AZO nanopowders could be effectively controlled by adding the mineralizer or not. With the increase of Al³⁺ doping content, the electrical resistivity of AZO microflowers decreased firstly and then increased, and which reaches a minimum value of ~647 Ω cm at 2 % Al³⁺ doping. The formation mechanism of the nanorod-constructed AZO microflowers was also discussed.     

Interfacial evolution in Sn–58Bi solder joints during liquid electromigration

For Sn–58Bi low temperature solder alloy, local molten induced from electromigration Joule heating might change the atomic diffusion and interfacial behavior. In this paper, the diffusion behavior and interfacial evolution of Cu/Sn–58Bi/Cu joints were studied under liquid–solid (L–S) electromigration in molten solder and were compared with the interfacial behaviors in solid–solid (S–S) electromigration in solid solder. L–S or S–S electromigration was realized by applying a current density of 1.0?×?10⁴ A/cm² to molten solder at 150 °C or solid solder at 25 °C, respectively. During S–S electromigration, Bi atoms were driven towards anode side under electromigration induced flux and then accumulated to form Bi-rich layer near anode interface with current stressing time increasing. During L–S electromigration, Bi atoms were reversely migrated from anode to cathode to produce Bi segregation at cathode interface, while Cu atoms were rapidly dissolved into molten solder from cathode and migrated to form large amounts of Cu₆Sn₅ rod-like phases near anode interface. The reversal in the direction of Bi atoms may be attributed to the reversal in the direction of electromigration induced flux and correspondingly the change on effective charge number of Bi atoms from negative to positive.     

Nb掺杂Bi4Ti3O12层状结构铁电陶瓷的电行为特性研究

采用固相烧结工艺制备了Nb⁵⁺掺杂的Bi₄Ti₃O₁₂层状结构铁电陶瓷.运用XRD 和AFM对Bi₄Ti_3-xNb_xO_12+x/2材料的微观结构进行表征,发现所制备的陶瓷均具有单一的正交相结构,抛光热腐蚀表面晶粒的显微形貌表现为随机排列的棒状结构.通过对材料直流电导率与温度关系的Arrhenius拟合,分析丁Bi₄Ti_3-xNb_xO_12+x/2的导电机理. Nb⁵⁺掺杂提高了材料的介电常数,但居里温度随掺杂含量的增加呈线性下降趋势.DSC结果显示Bi₄Ti_3-xNb_xO_12+x/2材料在居里温度处经历了一级铁电相变.样品的铁电性能测试结果表明, Nb⁵⁺掺杂Bi₄Ti₃O₁₂提高了材料的剩余极化Pr,这主要是由于^_Nb5+取代Ti⁴⁺大大降低了材料中氧空位的浓度,使得氧空位对畴的钉扎作用减弱的缘故.