硫族化合物半导体纳米材料的可控制备、生成机制和光电性能研究

发布时间：2018-04-04 19:14

本文选题：硫族化合物　切入点：半导体纳米材料　出处：《中国科学技术大学》2015年硕士论文

【摘要】：进入21世纪以来,全球范围内对太阳能电池的需求,每年以40%以上的速度增长。太阳能电池的应用是目前可再生能源研究的重点,太阳能吸收层作为太阳能电池的核心器件,其吸收层材料的种类也有很多,然而,大多数现有的高性能材料的应用因其利用率低,成本高,环境不相容性而受到限制。硫族化合物半导体纳米材料窄的直接带隙使其具有光学特性、电学特性、光电转化特性、光电催化特性,引起了人们极大的兴趣和关注。目前研究最多的是Ⅱ-Ⅵ(CdS,HgSe), Ⅳ-Ⅵ (PbS, PbSe)及多元硫化物半导体纳米材料如CuxS1-x, CIGS(CuInGaSe2), CZTS (Cu2ZnSnS4)。考虑到Cd和Hg有毒,铟和稼元素是稀土元素且价格昂贵,从而限制了其发展。S、 Cu、 Zn、 Ge元素年产量高、价格低并且低毒,在太阳能吸收层材料方面有着潜在的应用,适用于大规模、低成本的太阳能电池生产。本文在此背景下,围绕GeS、 GeSe和CZTS纳米材料的制备、表征及其在太阳能吸收层材料方面的应用开展了一系列工作,主要内容如下：一、介绍了一种简单的溶剂热法可控的合成GeSe单晶纳米结构。通过改变反应溶剂和反应物的量选择性的制备了GeSe纳米片和纳米带材料。通过XRD、EDX确定了产物的相与成分。并利用SEM、 TEM对他们的形貌、微结构以及生长方向等进行了表征与分析。对生成产物的反应条件和反应机理进行了探讨。二、采用简单的一步溶液法可控制备了GeS纳米片和GeS纳米线,研究了反应温度和反应时间对其形貌的影响,最后提出了纳米线的生长机理。利用XRD与EDX确定所合成的样品为GeS材料；利用SEM、TEM等表征手段研究了GeS纳米片、GeS纳米线的微结构以及形成机理。利用紫外-可见分光光度计测定了GeS纳米结构的光电性能,通过线性拟合得出了它们的带隙值。在反应过程中OLA作为活性剂和包覆剂,在GeS的生长过程中起了重要作用；通过控制反应温度和加热时间,可以得到纳米片和纳米线2种不同形貌的材料。最后对GeS纳米线提出了一种卷曲过程的生长机理：在温度升高的过程中,由于GeS纳米片和OLA的相互作用,使得GeS纳米片产生较强的表面张力,在这种驱动力下,使得GeS纳米片发生弯曲,最终形成纳米线结构。因此,制备不同形貌和尺寸的GeS纳米材料的研究推进了光伏吸收材料的进步,在光电材料领域中还有更大的研究空间。三、探讨了一步水热法合成二维结构的CZTS纳米片,使用CuCl2、 SnCl4、 ZnCl2作为金属前驱体,硫脲作为硫源,聚乙烯吡咯烷酮(PVP)作为表面活性剂。通过XRD、 EDX、 HRTEM和拉曼光谱对其物相、结构、形貌和光电性能进行了表征,结果显示制备的CZTS纳米片是半透明状且平均厚度在10nm左右。此外,文章讨论了PVP对CZTS结构和形态的影响；光电性能分析结果表明CZTS纳米晶体的带隙宽度约为1.48eV,是理想的薄膜太阳能电池材料；最后探讨了可能的生长机理。在这里,我们使用水作为溶剂,绿色无污染；制备方法简单、成本低,使其广泛应用于薄膜光伏电池的生产。
[Abstract]:Since twenty-first Century, global demand for solar cells, the annual growth rate of more than 40%. The application of solar cells is the focus of the current research on renewable energy, the solar energy absorbing layer as the core component of solar cells, the absorption type layer material also has a lot of application, however, most of the existing high performance materials for the low utilization rate, high cost, environmental compatibility is limited. Chalcogenide semiconductor nanomaterials narrow direct band gap which has optical properties, electrical properties, photoelectric conversion characteristics, photoelectric catalytic properties, has aroused great interest and attention. At present, most of the research is (CdS, II - VI HgSe), IV - VI (PbS, PbSe) and multiple sulfide semiconductor nano materials such as CuxS1-x, CIGS (CuInGaSe2), CZTS (Cu2ZnSnS4). Considering the Cd and Hg elements are toxic, indium and rare earth elements and the price of corn Expensive, which limits the development of.S, Cu, Zn, Ge elements with high yield, low price and low toxicity, have potential applications in solar energy absorption layer, suitable for mass production of solar cells, low cost. Based on this background, around GeS, GeSe and CZTS nanostructures characterization and application layer in solar absorption materials has carried out a series of work, the main contents are as follows:
First, introduces the synthesis of single crystal GeSe nano structure of a simple solvothermal method. Controlled by changing the reaction solvent and the reaction amount of selective preparation of GeSe nano film and nano belt materials. Through XRD, EDX to determine the phase components of the product. And the use of SEM and TEM on their morphology, micro the structure and growth direction were characterized and analyzed. The reaction conditions and reaction mechanism of the formation of the product were discussed.
The two step, using a simple solution method can control the synthesis of GeS nano films and GeS nanowires, studied the influence of reaction temperature and reaction time on the morphology, finally proposed the growth mechanism of nanowires. The synthesis using XRD and EDX samples for GeS materials; using SEM, TEM were used to study the micro structure of nano GeS, GeS nanowires and formation mechanism. By using UV visible spectrophotometry and optical properties of GeS nanostructures were determined by linear fitting, the value of their band gaps. In the reaction process of OLA as an active agent and coating agent, played an important role in the growth process of GeS in; by controlling the reaction temperature and heating time, can get nanosheets and nanowires of 2 different morphologies of materials. Finally, a curling process on the growth mechanism of GeS nanowires is proposed: in the process of temperature rise, due to nano GeS The interaction of OLA and GeS, the nano produced strong surface tension, the driving force, making GeS nano sheet bending, and ultimately the formation of nanowire structure. Therefore, study on Preparation of GeS nano materials with different morphologies and sizes of the advanced photovoltaic step absorbing materials, in the field of photoelectric material and greater research space.
Three, discusses the CZTS nanosheets, one-step hydrothermal synthesis of two-dimensional structure using CuCl2, SnCl4, ZnCl2 as a metal precursor, thiourea as sulfur source, polyvinylpyrrolidone (PVP) as a surfactant. Through XRD, EDX, HRTEM and Raman spectra of phase structure on the matter, and photoelectric properties the morphology was characterized, the results showed that CZTS nano film preparation is translucent and the average thickness is about 10nm. In addition, the article discusses the influence of PVP on the structure and morphology of CZTS; the analysis results show that the CZTS photoelectric properties of nano crystal band gap width is about 1.48eV, is the ideal material for thin film solar cell is discussed; the possible growth mechanism. Here, we use water as a solvent, no pollution to the environment; the preparation method is simple, low cost, it is widely used in solar cell production.

【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM914.4;TB383.1

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