Formation process of organic/inorganic superlattice structure using layered perovskite compounds with self-organization property

本研究的提出是为了阐明层状钙钛矿化合物形成超晶格的机理，优化制备高量子效率钙钛矿薄膜的蒸发条件。我们首先对原有的蒸发系统进行了改进，使其能够自动、实时地测量钙钛矿薄膜的吸收性能。考察了影响钙钛矿薄膜形成过程的因素，优化了获得高量子效率钙钛矿薄膜的条件。最后，我们将钙钛矿层组装成电致发光器件，并研究了器件的发射特性。研究了湿度对钙钛矿膜形成过程的影响。研究发现，湿度对形成过程有很大的影响。通过定量分析钙钛矿膜的湿度与吸波性能之间的关系，强烈建议采用…进一步研究表明，在形成过程中，PbI_2作为固定相，有机胺作为移动(迁移)相。湿度(水)主要影响迁移阶段，即加快迁移。研究还发现，在任何情况下，即使有机胺与PbI2的摩尔比远远超过一个单位，薄膜中仍有一些未反应的PbI2，并与钙钛矿型化合物共存。当有机胺与PbI2的摩尔比为3时，发光的量子效率最高。由此推测，在形成过程中，PbI2作为固定相，有机胺作为移动相。我们还发现，在200K左右的温度变化范围内，发射的量子效率可能会发生几十年的变化。这一大小意味着剩余的PbI2起到了抑制中心的作用。制备了以层状钙钛矿薄膜为发射层的电致发光器件。当在器件上施加直流电压时，观察到钙钛矿层发出明亮而尖锐的发射。这一现象意味着所使用的钙钛矿层具有足够的载流子输运能力，并且载流子复合可以发生在钙钛矿型化合物上。这一结果表明，将钙钛矿层用作光电器件的活性材料具有很大的可能性。较少

The propose of this research is to clarify the mechanism of the formation process of layered perovskite compounds formed superlattice and optimize the evaporation conditions in preparing perovskite film with high quantum efficiency We firstly improved the old evaporation system, and make it is possible to automatically and real-time measure the absorption property of the perovskite film. Then we invistgated some factors affecting the formation process of the perovskite film, optimized the conditions for getting perovskite film with high quantum efficiency. Finally we corporate the perovskite layer into an electrolumonescent device, and investigated the emission property of the device. The influence of the humidity on the formation process of the perovskite film was investigated. It was found that the humidity could strongly affect the formation process. By quantitative analyses of the relationship between the humidity and the absorption property of perovskite film, it was strongly sugg … More ested that, in the formation process, the PBI2 act as a fixed phase and the organic amine as a moving (migration) phase. The humidity (water) mainly affects the migration phase, i.e. speed up the migration. It also found that in any case, even the mole ratio of the organic amine against the PbI2 far exceeds a unity, there is still some un-reacted PbI2 remaining in the film, and co-exists with the perovskite compound. Highest quantum efficiency of the emission was get when the mole ratio of the organic amine against the PbI2 equals 3. From this result, it is speculated that, in the formation process, PbI2 acts as a fixed phase and organic amine acts as a moving phase. We also found that, in a temperature change range of about 200K, the quantum efficiency of the emission could changes by several decades. This big implies that the remained PbI2 acts as a quench center against the cxction. Electrolminescent device with the layered perovskite film as an emission layer fabricated. Bright and sharp emission from the perovskite layer was observed when a DC voltage was exerted on the device. This phenomenon implies that the used perovskite layer has enough carrier transport capability, and the carrier re-combination can occur at perovskite compound. This result shows us a great possibility to use perovskite layer as an active material in an opt-electronic device. Less