【作者】 谭晓艳；

【导师】 杨晴；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2011， 硕士

【摘要】 本论文的研究目标是探索和发展一种新的溶液相合成γ-In₂Se₃纳米材料的简单方法。研究中以乙醇溶剂热为体系研究不同反应条件对所制备γ-In₂Se₃纯相,切顶角六方双锥、球花多级结构的γ-In₂Se₃的形貌影响,并通过对所制备产物的进行表征和分析,探明球花多级结构的γ-In₂Se₃生长机理。主要内容总结如下:1.以四水合氯化铟,硒粉,乙醇为原料,在220 oC下反应20 h可以得到纯相的γ-In₂Se₃。反应温度,反应时间,反应物原料比例和浓度对产物的纯相合成影响较大。当InCl₃: Se粉的比例为1 : 1时产物不仅有γ-In₂Se₃,还有β-In₂Se₃和InSe;InCl₃: Se粉的比例为2: 3时,产物是γ-In₂Se₃和Se的混合物;高的InCl₃: Se粉的比例（4: 1）有利于得到纯相;温度低于220 oC时,Se粉未能完全反应;时间少于12 h时产物中也有硒粉未反应完全。此外还考察了加入其它反应溶剂,柠檬酸和聚乙二醇对产物形貌影响。2.在抗坏血酸的辅助下,以四水合氯化铟,硒粉220 oC下反应20小时首次合成出球花多级结构的γ-In₂Se₃。在该体系里,抗坏血酸同时作为还原剂和吸附剂。SEM, TEM和HRTEM等结果表明,球花多级结构的γ-In₂Se₃是由六方相γ-In₂Se₃纳米片组装而成。详细的时间追踪实验表明,球花多级结构是有普通球状的In₂Se₃通过Ostwald熟化转变而来。反应体系中的抗坏血酸的量和氯化铟的量对产物形貌的影响也做了仔细的研究。最后通过还通过将产物制备成膜测试了其电学性质,膜的电导率为2.6×10^-6 S cm^-1。更多还原

【Abstract】 The aim of this thesis is to develop a novel solution method for the synthesis of gamma phase indium selenide （γ-In₂Se₃） nanostructures. The effects on the structure and morphology of theγ-In₂Se₃ nanocrystals are investigated in the ethanol-solvothermal system route via the variation of reaction parameters. A possible growth mechanism of theγ-In₂Se₃ nanostructures is also proposed based on the characterization and analysis of products obtained in the process. The main contents of this work are summarized as follows:1. Pureγ-In₂Se₃ is fabricated by the reaction of indium chloride and selenium powders in the 220°C for 20 h in an ethanol-solvothermal system. The purity of the product is largely influenced by the reaction temperature, time and the quantity of reaction sources. When the ratio of InCl₃: Se is 1: 1, the product is a mixture ofγ-In₂Se₃,β-In₂Se₃ and InSe. While the ratio of InCl₃: Se is 1 : 1, we obtainγ-In₂Se₃ and Se. The pureγ- In₂Se₃ can be easily attained when the ratio of InCl₃: Se is 4: 1. However, with the high ratio of of InCl₃: Se, pureγ- In₂Se₃ is not synthesized if the temperature is lower than 220 oC nor the reaction time is less than 12 h. We also investigate the influence on the morphologies of the product by adding other solvents citric acid, or polyethylene glycol.2.γ-In₂Se₃ hierarchical flowerlike architectures have been facilely synthesized for the first time via the reaction of indium chloride and selenium powders with the assistance of ascorbic acid at 220°C for 20h in an ethanol-solvothermal system, in which ascorbic acid acts as both reducing and capping agent. SEM, TEM and HRTEM investigations show that these flowerlike In₂Se₃ architectures with hexagonalγ-phase structure are composed of thin sheet-like nanocrystals. The detailed time-dependent experiments illustrate that flowerlike architectures evolve from solid spheres via an Ostwald ripening process and the effects of the concentration of ascorbic acid and indium precursor on the phase and morphology evolution of In₂Se₃ flowerlike architectures are intensively studied. Meanwhile, the electrical property of theγ-In₂Se₃ film is investigated and the conductivity of the film is 2.6×10^-6 S cm^-1.更多还原