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

本研究的目的是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。首先改进了旧的蒸发系统，使自动实时测量钙钛矿薄膜的吸收性能成为可能。然后研究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，我们将钙钛矿层制成电致发光器件，并对器件的发射特性进行了研究。研究了湿度对钙钛矿薄膜形成过程的影响。研究发现，湿度对其形成过程有较大影响。定量分析了湿度与钙钛矿膜吸附性能的关系，结果表明，在钙钛矿膜的形成过程中，PBI2为固定相，有机胺为移动相。湿度（水）主要影响迁移阶段，即加速迁移。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，仍有一些未反应的PbI2残留在膜中，并与钙钛矿化合物共存。当有机胺与PbI2的摩尔比为3时，发光量子效率最高。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，在大约200K的温度变化范围内，发射的量子效率可以变化几十年。这意味着剩余的PbI2充当了抑制兴奋的猝灭中心。制备了以层状钙钛矿薄膜为发射层的电致发光器件。当直流电压施加在器件上时，观察到钙钛矿层发出明亮而锐利的发射。这一现象说明所使用的钙钛矿层具有足够的载流子输运能力，在钙钛矿复合物中可以发生载流子复合。这一结果显示了钙钛矿层在光电器件中作为活性材料的巨大可能性。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