铅锰钙钛矿材料的合成、表征及其光电特性研究

发布时间：2018-06-08 06:09

本文选题：钙钛矿 + 太阳能电池　；参考：《聊城大学》2017年硕士论文

【摘要】：近几年钙钛矿太阳电池发展迅猛,达到与晶体硅太阳能电池相媲美的水平,已达到了22%的光电转换效率,但其中钙钛矿材料的铅元素的毒性限制了该种太阳电池的应用潜力,研究开发低成本、高效率、环境友好的无铅太阳电池材料具有十分重要的意义。本论文拟首先通过对经典钙钛矿材料CH_3NH_3PbI_3的晶体结构的研究,然后设计合成新的无铅钙钛矿光电功能材料,进而构造成完整的钙钛矿太阳电池器件。多晶钙钛矿薄膜中存在着大量晶界、缺陷和陷阱态,因此很难确定钙钛矿的基本性质及其光电特性。单晶快速方便的培养方法之一是反溶剂扩散法。通过反溶剂扩散的方法我们培养出了CH_3NH_3PbI_3(MAPbI_3)的单晶,通过研究不同的扩散溶剂发现,在用乙醚、二氯甲烷、四氢呋喃、三氯甲烷作为扩散溶剂时,只有用乙醚作为扩散剂时可以通过扩散诱导的方法生长出CH_3NH_3PbI_3单晶;通过研究单晶的物相结构,揭示了形成钙钛矿单晶的机制;通过XRD研究发现,钙钛矿单晶是经过最初的层状PbI2结构然后转变为层状的Hx PbI2+x·xH2O,然后进一步转变为三维的MAPbI_3单晶。我们进一步考察了MAPbI_3单晶在六种溶液中的的溶解行为。研究结果表明,含有KI的溶液明显促进了MAPbI_3单晶的分解,而饱和的CH_3NH_3I(MAI)溶液明显抑制了MAPbI_3单晶结构的分解。最后,通过紫外可见吸收光谱和固体积分球漫反射光谱和稳态荧光光谱对MAPbI_3单晶的光电特性进行了研究,研究结果表明MAPbI_3单晶的带隙为1.5 eV,其776 nm处的荧光峰小于UV-vis吸收的截止边缘,因此单晶体系中可以产生激子的二次利用。尽管CH_3NH_3PbI_3钙钛矿效率较高,但是其结构中含有重金属Pb,毒性较大,如果产业化之后对环境势必产生较大的影响。设计合成新的无铅有机无机钙钛矿材料并研究其光电性能,具有很强的理论意义和现实意义。本论文通过缓慢降温挥发溶剂的方法,合成了无铅的有机无机层状钙钛矿(CH_3NH_3)2MnCl_4单晶;二氧化钛薄膜控制了(CH_3NH_3)2MnCl_4薄膜主要沿着(010)晶向生长。在组装成完整的太阳能电池器件后,测试发现其具有明显的光电压和光电流响应。设计合成出了无铅的有机无机钙钛矿材料a-CH_3NH_3MnI_3(a-MAMnI_3),通过利用紫外可见吸收光谱对其薄膜进行研究,发现a-MAMnI_3的吸收特性与经典钙钛矿材料MAPbI_3的相符,但是吸收强度不如含铅钙钛矿的强,这也可能是导致后面光电响应较低的原因之一。通过制备成完整的太阳能电池器件,研究了器件的光电特性,发现具有明显的光电响应,并且稳定性较好;通过测试不同波长单色光下的光电响应,发现300 nm、460 nm、530 nm的单色光可以作为a-CH_3NH_3MnI_3光电器件的有效波长。同时,还进行了不同溶液中溶解性测试,与其XRD测试结果分析是相符的。
[Abstract]:In recent years, perovskite solar cells have developed rapidly, reaching a level comparable to that of crystalline silicon solar cells, and the photovoltaic conversion efficiency has reached 22%. However, the toxicity of lead in perovskite materials limits the application potential of this kind of solar cells. It is of great significance to study and develop low-cost, high-efficiency and environmental-friendly lead-free solar cell materials. In this thesis, the crystal structure of the classical perovskite material CH3NH3PbI3 is studied, then a new lead-free perovskite photovoltaic material is designed and synthesized, and a complete perovskite solar cell device is constructed. There are a large number of grain boundaries, defects and trap states in polycrystalline perovskite films, so it is difficult to determine the basic properties and photoelectric properties of perovskites. One of the rapid and convenient methods for the cultivation of single crystals is the anti-solvent diffusion method. Through the method of anti-solvent diffusion, we have grown the single crystal of Ch _ 3NH _ 3PbI _ 3MAPbI _ 3). By studying different diffusion solvents, we found that when using ether, dichloromethane, tetrahydrofuran and trichloromethane as diffusion solvents, Only when ether is used as diffusion agent can the Ch _ s _ 3NH _ 3PbI _ 3 single crystal be grown by diffusion-induced method. The mechanism of the formation of perovskite single crystal is revealed by studying the physical phase structure of the single crystal. Perovskite single crystal is transformed into layered Hx PbI2 x xH2O after initial layered PbI2 structure, and then further transformed into 3D MAPbI3 single crystal. We have further investigated the dissolution behavior of MAPbI3 single crystals in six solutions. The results show that the solution containing Ki can obviously promote the decomposition of MAPbI3 single crystal, while the saturated CHS _ 3NH _ 3i _ (MAI) solution obviously inhibits the decomposition of MAPbI _ 3 single crystal structure. Finally, the optical and electrical properties of MAPbI _ 3 single crystal were studied by UV-Vis absorption spectrum, solid integral sphere diffuse reflectance spectroscopy and steady-state fluorescence spectrum. The results show that the band gap of MAPbI3 single crystal is 1.5 EV, and the fluorescence peak at 776 nm is smaller than the cutoff edge of UV-vis absorption. Although the efficiency of Ch _ 3NH _ 3PbI _ 3 perovskite is relatively high, its structure contains heavy metal Pb, which is more toxic. If it is industrialized, it will have a great impact on the environment. It is of great theoretical and practical significance to design and synthesize new lead-free organic and inorganic perovskite materials and to study their photoelectric properties. In this paper, the lead-free organic-inorganic layered perovskite CH3NH3 / 2MnCl4 single crystal has been synthesized by the method of slow cooling volatile solvent, and the titanium dioxide thin film has controlled the growth of Ch _ 3H _ 3NH _ 3N _ 2MnCl _ 4 thin film along the crystal direction of Ch _ (010). After assembling the whole solar cell, it is found that the photovoltage and photocurrent response are obvious. A lead-free organic and inorganic perovskite material a-CHS _ 3NH _ 3NH _ 3MnI _ 3C _ 3 / MAMnI _ 3 has been designed and synthesized. By using UV-Vis absorption spectra to study its thin films, it has been found that the absorption characteristics of a-MAMnI _ 3 are consistent with those of the classical perovskite material MAPbIstructure _ 3, but the absorption intensity is not as strong as that of lead-containing perovskite. This may also be one of the reasons behind the lower photoelectric response. The photovoltaic characteristics of the device are studied by the fabrication of a complete solar cell device. It is found that the photovoltaic response is obvious and the stability is good, and the photoelectric response under different wavelength monochromatic light is tested. It has been found that the monochromatic light of 300 nm, 460 nm and 530 nm can be used as the effective wavelength of a-CH3NH3MnIstructure. At the same time, the solubility of different solutions was tested, which was consistent with the XRD results.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34;TM914.4

【相似文献】