有机—无机杂化钙钛矿材料的可控制备及其发光器件应用研究

发布时间：2018-01-26 21:33

本文关键词： 有机-无机杂化钙钛矿 CH_3NH_3PbI_3 CH_3NH_3PbBr_3 溶液法气相辅助溶液法发光二极管　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：有机-无机杂化钙钛矿材料由于其优异的光电性能越来越受到人们的重视。这一热潮最初是由钙钛矿太阳能电池引起的,这种新型的太阳能电池在较短的时间内就已经展现出大于20%的高转换效率。伴随着人们对该新型材料的理解和认识,基于钙钛矿材料的研究领域已经开始扩展,其在发光领域的潜在应用使得研究人员在高亮度发光二极管(LED)和激光器的制备方面看到了新的希望。由于它们具有在可见光到近红外区域中光学带隙可调的特性,结合它们的低温溶液处理方法,这些材料也被视为发光器件应用的理想候选者。基于这种新兴材料的电致发光器件具有高量子效率、发光波长可调、双极性电子传输和高的色纯度等优异特性,有可能在未来的显示、照明和光通讯等领域取得广泛的应用。本论文选择有机-无机杂化钙钛矿材料中的CH_3NH_3PbI_3和CH_3NH_3PbBr_3为研究对象,开展了薄膜的优化生长研究,对其形貌、结晶和光学特性进行表征分析,设计并制备了CH_3NH_3PbBr_3基绿光LED,并对其电学特性和稳定性进行了探究。主要有以下几个方面:1.在两步溶液法合成CH_3NH_3PbI_3薄膜的基础上,通过改变前驱液中Pb I2溶液的高速旋涂速率、薄膜的退火温度和前驱液中CH3NH3I/PbI2的比例进行优化生长并制备出高质量的CH_3NH_3PbI_3薄膜。通过测试分析发现,制备出的薄膜具有低缺陷密度、较高的相纯度和优异的发光特性,适合作为发光层用在发光器件中。为了进一步了解薄膜光学特性,我们对其做了变温PL测试,使我们对钙钛矿材料低温条件下的相变过程和激子辐射复合过程有了更深一层的了解。2.在一步溶液法形成的CH_3NH_3PbBr_3薄膜的基础上,我们对其进行优化生长,如改变前驱液的旋涂速率和退火温度或使用DMF/HBr共溶剂,均不能得到形貌特性与光学特性俱佳的高质量薄膜。因此,我们使用气相辅助溶液法对其进行优化生长,通过控制蒸发过程中的蒸发时间和温度,最终制备出高覆盖密度和发光性能的CH_3NH_3PbBr_3薄膜。3.使用两步溶液法制备出的CH_3NH_3PbBr_3薄膜具有优异的成膜和光学特性。通过设计ZnO/CH_3NH_3PbBr_3/PEDOT:PSS简单三明治结构,我们初步实现了CH_3NH_3PbBr_3基绿光LED的制备。对其电学特性进行系统性的分析,得到器件的开启电压为2.8V,在9.0V的电压下,器件EQE达到了0.0645%,虽然远低于预期,但仍然具有优化的空间。此外,我们还对二极管的工作稳定性进行了调查分析,发现器件性能对环境氛围具有很高的灵敏度,而且其发光效率的衰减是不可逆的。有效解决发光层对环境的敏感性问题、优化器件的结构设计以及增加器件的工作稳定性等,钙钛矿基发光二极管的制备和在实际生活中应用将充满希望。
[Abstract]:Organic-inorganic hybrid perovskite materials have attracted more and more attention due to their excellent photoelectric properties. This upsurge was initially caused by perovskite solar cells. This new type of solar cell has shown a high conversion efficiency of more than 20% in a relatively short period of time, along with the understanding and understanding of the new material. The research field based on perovskite materials has begun to expand. Its potential applications in the field of luminescence have led researchers to develop LEDs in high brightness LEDs. Because of their tunable optical band gap in the visible to near infrared region. In combination with their low-temperature solution treatment, these materials are also considered as ideal candidates for luminescent device applications. The electroluminescent devices based on this new material have high quantum efficiency and tunable luminescence wavelength. Excellent features such as bipolar electron transport and high color purity are likely to be displayed in the future. Lighting and optical communication have been widely used. In this thesis, CH_3NH_3PbI_3 and CH_3NH_3PbBr_3 in organic-inorganic hybrid perovskite materials are selected as research objects. The optimized growth of the thin films was studied, the morphology, crystallization and optical properties of the films were characterized, and the green LED based on CH_3NH_3PbBr_3 was designed and prepared. The electrical properties and stability of CH_3NH_3PbI_3 thin films were investigated. There are several aspects as follows: 1. On the basis of two-step solution synthesis of CH_3NH_3PbI_3 thin films. By changing the high speed spin-coating rate of Pb I 2 solution in the precursor solution. The annealing temperature and the ratio of CH3NH3I/PbI2 in the precursor were optimized and high quality CH_3NH_3PbI_3 thin films were prepared. The prepared thin films have low defect density, high phase purity and excellent luminescent properties, so they are suitable for use in luminescent devices in order to further understand the optical properties of the films. We tested it with variable temperature PL. We have a deeper understanding of the phase transition process and the exciton radiation recombination process at low temperature. 2. On the basis of the CH_3NH_3PbBr_3 thin films formed by one-step solution method. We optimized the growth, such as changing the spin-coating rate and annealing temperature of the precursor solution, or using DMF/HBr co-solvent, can not obtain high quality films with good morphology and optical properties. The vapor-assisted solution method is used to optimize the growth, and the evaporation time and temperature are controlled. Finally, the CH_3NH_3PbBr_3 thin films with high coverage density and luminescence properties were prepared. 3. The CH_3NH_3PbBr_3 thin films prepared by two-step solution method have excellent film formation and excellent luminescence properties. Optical properties. By designing ZnO / Ch / S 3NH3PbBrs, 3 / P PEDOT:. PSS simple sandwich structure. We have preliminarily realized the preparation of CH_3NH_3PbBr_3 based green light LED. The electrical characteristics of the device are systematically analyzed and the opening voltage of the device is 2.8 V. At the voltage of 9.0V, the device EQE reaches 0.06455.Although it is far lower than expected, there is still room for optimization. In addition, we also investigate and analyze the stability of the diode. It is found that the performance of the device is highly sensitive to the ambient atmosphere, and the decay of its luminous efficiency is irreversible, which effectively solves the problem of environmental sensitivity of the luminescent layer. The fabrication and application of perovskite-based light-emitting diodes (PLEDs) will be promising due to the optimization of the device structure and the enhancement of the stability of the devices.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O484.41;TN312.8

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