Zhongyuan YU
,
Yongqiang WEI
材料科学技术（英文）
The effect of different kinds of cap layers on optical property of InAs quantum dots (QDs) on GaAs (100) substrate was studied. Temperature dependent photoluminescence (PL) indicates that the PL integrated intensity from the ground state of InAs QDs capped with an intermediate InAlAs layer drops very little as compared to QDs capped with a thin InGaAs or GaAs cap layer from 15~K up to room temperature. PL integrated intensity ratio of the first excited to ground states for InAs QDs capped with an intermediate InAlAs layer is unexpectedly decreased with increasing temperature, which are attributed to phonon bottleneck effect. A virtual barrier is proposed to describe this physics process and shows good agreement with experimental results when fitting the curve with the value of the virtual barrier 30 meV.
关键词:
Quantum dots
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null
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null
Hui She
材料科学技术（英文）
The vertical and lateral interactions in a multisheet array of InAs/GaAs quantum dots are analyzed by finite element method (FEM). It is shown that due to the effects of vertical interaction, nucleation prefers to happen above buried quantum dots (QDs). Meanwhile, the effects of lateral interaction adjust the spacing of lateral neighboring QDs. The vertical coupling becomes strong with deceasing GaAs spacer height and increasing number of buried layers, while the lateral coupling becomes strong with increasing InAs wetting layer thickness. The phenomenon that, after successive layers, the spacing and size of QDs islands become progressively more uniform is explained according to the minimum potential energy theory.
关键词:
Quantum dots
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null
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null
初丛波
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单玉萍
,
王宏达
应用化学
doi:10.3724/SP.J.1095.2014.30457
过去十几年里,量子点从材料科学到生命科学、从基础研究到实际应用都开展了广泛的研究.量子点在生物成像、光治疗、药物/基因转运、太阳能电池等领域均具有广泛的应用.通过调节量子点的表面性质,实现量子点与细胞相互作用的可控性是一个关键的问题.伴随着量子点潜在毒性问题的产生,纳米毒性成为纳米材料安全性评估的重要指标,并且受到科学家们的高度关注.本文综述了量子点的特性、细胞生物学应用及在生物医药领域相关的细胞毒性研究,并展望了量子点的未来发展趋势.
关键词:
量子点
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生物应用
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荧光标记
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细胞毒性
潘伦
,
张靖雯
,
贾旭
,
马煜航
,
张香文
,
王莅
,
邹吉军
催化学报
doi:10.1016/S1872-2067(16)62576-7
TiO2具有高效、廉价、无毒及光化学稳定性好等优点,因而被广泛应用于光能转化和利用领域,如太阳能电池、光催化分解水制氢和环境污染物降解等.但是,TiO2仍然存在一些缺陷制约了其应用,其中,最关键的问题是光生电荷分离效率低.因此,人们对其进行了掺杂、异质结构建和Z型结构建等来解决这一问题,其中Z型结近年来备受关注.全固体Z型结的构建目前主要有两种方式:PSI-C-PSII和PSI-PSII.前者PSI与PSII间要插入中间导电层(如Au、rGO等)来实现界面欧姆接触;后者则无中间层,而是基于界面设计来实现欧姆接触.本文以构建PSI-PSII Z型结为目标,以TiO2和WO3为基础半导体材料,采用原位溶剂热生长的方法构建WO3量子点/TiO2结构,借助氢气还原反应在界面处引入氧缺陷.采用透射电子显微镜、X射线衍射和拉曼光谱研究了复合晶体结构,采用X射线光电子能谱、紫外可见光谱和荧光光谱等手段研究了Z型结的界面结构和能带结构.结合光催化分解水产氢活性来建立Z型结结构与光催化性能的关联关系.表征结果表明,在TiO2上进行原位溶剂热成核反应可点缀WO3量子点,并且量子点粒径随W前驱体用量的增加而变大.两种半导体材料为TiO2锐钛矿和WO3晶体结构,且WO3的XRD特征峰和Raman特征吸收峰会随W前驱体用量增加而变大.通过对WO3/TiO2进行氢气还原处理,使其表面形成大量W5+和氧缺陷,一方面提高了催化剂对可见光的吸收,另一方面在界面形成欧姆接触,实现了Z型结构的构建.Z型结构实现了光催化分解水产氢反应,其中WTH10光催化活性最好.本文为新型Z型光催化剂的设计和构建提供了新思路和策略.
关键词:
WO3?x
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二氧化钛
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产氢
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量子点
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W5+/氧缺陷
