7003全讯入口“博约学术沙龙”系列报告 (总第 127 期)
来源: 作者: 发布时间:2016-11-15邀请人:
报告人:
时间: 2016-11-15
地点:
主讲人简介:
地 点: 中心教学楼610
题 目:Emulsion Synthesis of Size-Tunable CH3NH3PbBr3 Quantum Dots: An Alternative Route toward Efficient Light-Emitting Diodes
报告人:黄海龙 指导老师:石丽洁、钟海政
摘要:
We report a facile nonaqueous emulsion synthesis of colloidal halide perovskite quantum dots by controlled addition of a demulsifier into an emulsion of precursors. The size of resulting CH3NH3PbBr3 quantum dots can be tuned from 2 to 8 nm by varying the amount of demulsifier. Moreover, this emulsion synthesis also allows the purification of these quantum dots by precipitation from the colloidal solution and obtains solid-state powder which can be redissolved for thin film coating and device fabrication. The photoluminescence quantum yields of the quantum dots are generally in the range of 80−92%, and can be well-preserved after purification (∼80%). Green light-emitting diodes fabricated comprising a spin-cast layer of the colloidal CH3NH3PbBr3 quantum dots exhibited maximum current efficiency of 4.5 cd/A, power efficiency of 3.5 lm/W, and external quantum efficiency of 1.1%. This provides an alternative route toward high efficient solution-processed perovskite-based light-emitting diodes. In addition, the emulsion synthesis is versatile and can be extended for the fabrication of inorganic halide perovskite colloidal CsPbBr3 nanocrystals.
报告二:硕士生报告 时间:14:30-15:00
题 目:多肽保护金团簇结构与合成的相关研究
报告人: 李楠 指导老师:赵宏康
摘要:
多肽保护的金纳米团簇是团簇功能化的纳米级团簇,具有生物相容性好等独特的物理化学性质,主要用于生物医学研究与应用,诸如疾病早期诊断、癌症的靶向治疗等。由于多肽保护层赋予了金团簇新的结构特性,因此在生物医学应用上发挥了独特的生物效应。本研究主要运用第一性原理探究以下内容:研究氨基酸的反应活性;运用具有还原性的氨基酸序列(CCY)合成金团簇时研究金团簇原位合成机制;在氨基酸配体保护的金团簇中,研究配体对金核结构的调制。DFT方法通过计算体系的电子结构,能够研究纳米/生物界面反应过程,有效理解生物效应的分子机制。进一步,多肽保护金团簇结构与合成的研究对生物医学应用具有指导意义。
报告三:硕士生报告 时间:15:00-15:30
题 目: 铜掺杂氧化锌薄膜的制备及其结构、形貌和光学特性研究
报告人: 周佩佩 指导老师:王志
摘要:
本文采用磁控共溅射方法在玻璃基片上制备了纯ZnO和Cu掺杂ZnO薄膜,并通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)、紫外-可见分光光度计(UV-Vis)对样品进行了表征和分析探究基片温度、Cu掺杂量等因素对薄膜结构、形貌、光学性能的影响。
实验中,我们采用双靶共溅射制备Cu掺杂ZnO薄膜,通过调节Cu的溅射功率和挡板的周期开闭来得到不同的少量的掺杂量。结果显示所有薄膜都呈现单一相的六方纤锌矿结构,适当的高温,提高薄膜结晶度高,减少了薄膜的压应力。Cu掺杂和基底温度的增加导致薄膜表面更为粗糙和颗粒尺寸相对变大。纯氧化锌和Cu掺杂氧化锌薄膜的电阻率随着基底温度的升高而增加,然而未掺杂的薄膜的带隙随着温度的变化却不明显。铜掺杂量是影响Cu掺杂氧化锌薄膜的物理性质的重要因素。Cu掺杂降低了电阻率,导致吸收边的红移,使氧化锌薄膜的带隙变窄。
Undoped and Cu-doped ZnO (ZnO:Cu) thin films were prepared using magnetron co-sputtering. Effects of substrate temperature Ts on their structural, electrical and optical properties were comparatively investigated using X-ray diffraction, atom force microscopy, and ultraviolet visible spectrophotometer. ZnO:Cu thin films with different doping content were prepared and studied in order to investigate the effects of Cu-doping content.
The results show that all the films exhibit a single phase (002)oriented hexagonal wurtzite structure. Higher Ts enhances the crystallinity and reduces the compressive stress of the films. Cu-doping and increasing Ts lead to rougher surface and larger granules. The resistivity of both the ZnO and ZnO:Cu films increases with Ts. Interestingly, optical band gap Eg of ZnO:Cu films increases significantly with Ts, while Eg of undoped film is not obviously influenced by Ts. Cu-doping content is an important factor affecting the physical properties of ZnO:Cu thin films. In our experiments, Cu-doping composition sightly decreases with Ts increasing. Cu-doping reduces the resistivity, leads to the red-shift of absorption edge, and narrows Eg of ZnO thin films.
报告四:硕士生报告 时间:15:30-16:00
题 目: 过渡金属掺杂锐钛矿TiO2(101)面的改性研究
报告人: 苏巧智 指导老师:江兆潭
摘要:
采用密度泛函理论的平面波超软赝势方法,对过渡金属Fe、Ni、Pd、Pt、Cu、Ag和Au在锐钛矿TiO2(101)面上的掺杂改性开展了系统深入的理论研究。通过计算和分析锐钛矿TiO2(101)面掺杂前后的几何结构、电子结构和光学性质等,揭示了宏观催化活性与微观结构、光电子特性之间的关联。结果表明:过渡金属掺杂能减小禁带宽度或引入杂质能级, 从而提高TiO2(101)面的可见光响应;杂质能级通常位于禁带内,其形成主要由过渡金属的d电子态贡献;不同过渡金属掺杂的TiO2(101)面具有不同的光催化性能,这与掺杂后的禁带宽度、杂质能级的形成位置以及过渡金属原子的最外层电子排布等有关。本研究能够为TiO2光催化剂的结构设计与改性提供理论依据。