Defects such as uncoordinated lead ions and surface charged defects are still one of critical issues for perovskite light-emitting diodes (PeLEDs). The presence of these defects can trap excitons, resulting in enhanced nonradiative recombination and thus poor efficiencies of PeLEDs. Defect passivation via passivation agents is an effective way to solve this issue. In this work, we introduce a bifunctional phosphate molecule 6,6'-(ethane-1,2-diyl)bis(dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (DIDOPO) as a passivation agent into the perovskite, where DIDOPO can bind with the perovskite via the chemical interaction between the P=O groups and uncoordinated Pb ions. Thus, the incorporation of DIDOPO effectively passivates the defects, leading to improved radiative recombination. Simultaneously, the as-prepared perovskite film produces dense and smooth morphology, which is favorable to good contact with the adjacent charge transport layers and the reduction of leakage current. As a result, the sky-blue PeLEDs modified by DIDOPO show improved efficiency with the maximum EQE of 5.52% and the average EQE of 5.09%. Furthermore, attributed to the alkyl chain as the bridge between the phosphate groups, DIDOPO accumulated at the perovskite surface is able to decrease hydrophilic behavior of the perovskite. The PeLEDs containing DIDOPO possess enhanced moisture resistance, remaining ca. 91-92% of the initial EQE after storage for 120 h in ambient atmosphere with the humidity of ca. 40%.

铅离子不协调和表面带电缺陷等缺陷仍然是钙钛矿发光二极管 (PeLED) 的关键问题之一。这些缺陷的存在会俘获激子，导致非辐射复合增强，从而导致 PeLED 效率低下。通过钝化剂进行缺陷钝化是解决这一问题的有效方法。在这项工作中，我们将双功能磷酸盐分子 6,6'-(乙烷-1,2-二基)双(二苯并[c,e][1,2]氧代膦酸 6-氧化物) (DIDOPO) 作为钝化剂引入到钙钛矿，其中 DIDOPO 可以通过 P=O 基团和未配位的 Pb 离子之间的化学相互作用与钙钛矿结合。因此，DIDOPO 的加入有效地钝化了缺陷，从而改善了辐射复合。同时，所制备的钙钛矿薄膜形貌致密光滑，有利于与相邻电荷传输层的良好接触，降低漏电流。因此，经 DIDOPO 改性的天蓝色 PeLED 显示出更高的效率，最大 EQE 为 5.52%，平均 EQE 为 5.09%。此外，由于烷基链作为磷酸基团之间的桥梁，钙钛矿表面积累的 DIDOPO 能够降低钙钛矿的亲水行为。含有 DIDOPO 的 PeLED 具有增强的防潮性，保持约 储存 120 年后初始 EQE 的 91-92% 由 DIDOPO 改性的天蓝色 PeLED 显示出更高的效率，最大 EQE 为 5.52%，平均 EQE 为 5.09%。此外，由于烷基链作为磷酸基团之间的桥梁，钙钛矿表面积累的 DIDOPO 能够降低钙钛矿的亲水行为。含有 DIDOPO 的 PeLED 具有增强的防潮性，保持约 储存 120 年后初始 EQE 的 91-92% 由 DIDOPO 改性的天蓝色 PeLED 显示出更高的效率，最大 EQE 为 5.52%，平均 EQE 为 5.09%。此外，由于烷基链作为磷酸基团之间的桥梁，钙钛矿表面积累的 DIDOPO 能够降低钙钛矿的亲水行为。含有 DIDOPO 的 PeLED 具有增强的防潮性，保持约 储存 120 年后初始 EQE 的 91-92% h 在环境大气中，湿度为约。40%。