高效有机-无机复合阳离子蓝光钙钛矿量子点发光二极管材料与器件研究

The emerging perovskite quantum dot light-emitting diode (PeLED) become the promising candidates in the low-cost, wide color gamut, and flexible display area with huge marketing potential. Despite the great efforts devoted, up-to-date, the highest external quantum efficiency (EQE) reported for the blue PeLED is only 2.6%, which is one of the main threats for the development of full color PeLED. Sever issues, including trap centers at the surface of perovskite quantum dots (PQDs), unbalance of carrier injection, interface defects and limitation of light extraction of PeLED, result in the dramatic decrease of EQE of blue PeLED. In this project, focus is put on the realization of highly efficient blue PeLED through material synthesis optimization, carrier dynamics elaboration, device fabrication and characterization. Firstly, the underlying principles are well explained of the innovative PCI method targeting at high quantum yield (QY) blue perovskite quantum dots (PQDs) along with optimization of the material synthesis. Beyond that, a novel compositional strategy of organic-inorganic hybrid A+ cation doping is created to effectively tune the bandgap so as to lower the interface energetic barrier of the blue PQDs to enhance the hole injection efficiency and balance the electron and hole injection. Based on the well control over the PQDs, interfaces among the blue PQDs active layer and the rest carrier transportation/collection layers are also paid great attention. Through optimization and passivation of these interfaces, their influences are unraveled on how to improve the quality of the synthesized film, lower the leakage current and defect density, and control over the transportation and injection of the carriers. On the device level, through construction of the physical model of the photons transportation, the hidden dynamics of the carriers are elucidated. The pathways are unraveled of the photon generation, transportation, dissipation, and emission within the blue PeLEDs. On the basis of that, the optical micro-nano structures are incorporated to further boost the light extraction efficiency to a new level. Combining all these, this research will lay the theoretical and technological foundation for the development of bright and highly efficient blue PeLED.

新兴的钙钛矿量子点发光二极管（PeLED）在低成本、宽色域、柔性显示领域具有巨大应用前景。目前蓝光PeLED外量子效率（EQE）已报道的最高仅为2.6%，已成为制约高效全彩色PeLED发展的主要瓶颈之一。蓝光钙钛矿量子点（PQDs）表面缺陷态，及蓝光PeLED载流子注入失平衡、界面缺陷、取光受限等问题的存在严重降低了蓝光PeLED效率。本项目围绕实现高效蓝光PeLED开展研究，阐明新型极性溶剂调控离子化方法（PCI）实现高量子产率蓝光PQDs的作用机理，优化材料制备工艺；建立通过A位有机-无机复合阳离子掺杂实现蓝光PQDs能带调控以减小界面势垒的方法，提高空穴注入效率，平衡载流子注入；明确蓝光PeLED中界面优化与钝化对减少界面缺陷、提高成膜性的作用关系；优化微纳光学结构，提高取光效率；多因素协同优化共同提升EQE。本项目的研究将为高效蓝光PeLED材料与器件的研制提供理论支持和技术指导。

钙钛矿发光二极管（Perovskite LED，PeLED）已成为新型显示发光材料与器件的重要研究方向。本项目针对蓝光PeLED所面临的主要挑战，开展了高效率蓝光PeLED材料和器件的基础研究。在理论上：阐明了PeLED中光子产生、传输、耗散与出射的机理与途径，建立了光子在器件中传输的物理模型；明晰了PeLED中载流子输运特性；阐明了双官能团配体对同时钝化缺陷和搭建起钙钛矿之间载流子传递桥梁的作用机制。在技术方法上：提出了基于光学隧穿的PeLED光提取方案；提出了引入电偶极层增强PeLED空穴注入的新方法；引入双官能团配体，在钝化缺陷的同时，减小钙钛矿之间的范德华间隙，搭建起载流子传递的桥梁。最终实现高效蓝光PeLED，准二维蓝光PeLED的EQE高达11.5%，位于目前蓝光PeLED最高性能之列。本项目为高性能蓝光PeLED的实现提供了新的解决思路，为高性能蓝光PeLED的未来产业化实现奠定理论和技术基础。..本项目期内，申请人诱发受资助国家级项目1项（国家优秀青年科学基金）；申请人在Advanced Materials、Advanced Science、ACS Energy Letters等学术期刊以通讯作者发表相关SCI论文42篇（影响因子 IF>10论文17篇）；EI 论文4篇；申请中国发明专利5项；获得广东省自然科学奖二等奖1项（已公示）；培养博士毕业生2人，硕士毕业生3人；受邀参加6次国内外高水平学术会议并作邀请报告。所获得的成果达到并超过项目计划书所要求的全部指标（请详见报告正文和附件证明材料）。同时，资金使用符合《国家自然科学基金资助项目资金管理办法》要求。