基于山梨醇钝化的绿光多晶薄膜钙钛矿发光二极管

Green Light-emitting Diodes Based on Sorbitol-passivated Perovskite Polycrystalline Films

金属卤化物钙钛矿具有高的缺陷容忍度、可调的发光峰位与较窄半峰宽等优异光电特性,在开发高性能发光二极管方面展现出巨大潜力。钙钛矿发光二极管的低成本溶液制备有利于其应用于显示与照明领域的大规模商业化生产,但溶液成膜过程中伴随着有机溶剂的挥发,成膜时易形成缺陷态,不利于高性能器件的实现。在钙钛矿前驱体溶液中引入添加剂是一种简单有效的钙钛矿缺陷钝化策略,其中,路易斯碱被证明是非常有效的添加剂之一。基于此,本文提出在前驱体溶液中引入小分子路易斯碱添加剂(山梨醇)来钝化薄膜缺陷,并制备了钙钛矿发光二极管。研究证明,山梨醇的引入可以明显改善薄膜质量,且山梨醇浓度为0.3mol·L^(-1)时,制备的器件实现了最佳电致发光性能,如最大外量子效率和亮度分别达到6.71%和7654 cd·m^(-2),且器件展现出较好的光谱稳定性与重复性。本工作对改善多晶薄膜成膜质量和提高钙钛矿发光二极管器件方面具有重要意义。

Metal halide perovskite has excellent photoelectric characteristics such as high defect tolerance,tunable peak position and narrow full width at half maximum,which exhibits great potential in the development of high-performance light-emitting diodes.Perovskite light-emitting diodes can be applied to the large-scale commercial production in the display and lighting fields due to low-cost solution preparation.However,the adverse defects are formed in the process of film formation accompanied by the organic solvent volatilization,which are not conducive to the realization of high performance devices.Introducing additive in perovskite precursor solution is a simple and effective strategy to passivate defects.It is reported that the Lewis base is one of the effective additives.Based on analysis,in this work,we propose to introduce a small molecule Lewis base additive(sorbitol)into the precursor solution to passivate the defects of perovskite film,and fabricate perovskite light-emitting diodes.The experiment results show that the introduction of sorbitol can significantly improve the film quality.And when the concentration of sorbitol is 0.3 mol·L^(-1),the corresponding device achieves the best electroluminescence performance with the maximum external quantum efficiency and luminance of 6.71%and 7654 cd·m^(-2),respectively.In addition,the resulting device also shows good spectral stability and repeatability.This work is of great significance to improve the polycrystalline film forming quality and boosting the performance of perovskite light-emitting diodes.