The thermal stability of organic functional materials affects the performance and lifetime of organic light-emitting diodes (OLEDs). We have developed a thermally stable inverted OLEDs (IOLEDs) by employing silver (Ag) doped into 4,7-diphenyl-1,10-phenanthroline (Bphen) as an n-type doped electron injection layer (EIL). We found that the formation of Ag complexes by coordination reaction could enhance the thermal stability and produce an asymmetric diffraction pattern based on an analysis of grazing incidence small angle X-ray scattering. Interestingly, with the annealing temperature increasing to 100 °C, the electrical properties of electron-only cells show differentiated phenomenon that the current density based on Ag dopant remains basically unchanged, which is opposite to Cs₂CO₃ dopant. In addition, at the high temperature of 100 °C, the IOLEDs with Cs₂CO₃ doped Bphen as an EIL was damaged completely, while the Ag dopant-based devices still maintained good photoelectrical characteristics. Finally, we have demonstrated that the optimized IOLEDs achieved a 40.3% enhancement in current efficiency compared to the conventional device. This work provides a new strategy to increase the thermal stability and performance for the application of IOLEDs operated under high temperature.

有机功能材料的热稳定性影响有机发光二极管 (OLED) 的性能和寿命。我们通过将银 (Ag) 掺杂到 4,7-二苯基-1,10-菲咯啉 (Bphen) 中作为n型掺杂电子注入层 (EIL)，开发了一种热稳定的倒置 OLED (IOLED )。我们发现，基于掠入射小角 X 射线散射的分析，通过配位反应形成的 Ag 配合物可以提高热稳定性并产生不对称的衍射图案。有趣的是，随着退火温度升高到 100 °C，纯电子电池的电学性质表现出分化现象，即基于 Ag 掺杂剂的电流密度基本保持不变，这与 Cs ₂ CO正好相反。₃掺杂剂。此外，在 100 °C 的高温下，以 Cs ₂ CO ₃掺杂 Bphen 作为 EIL的 IOLED完全损坏，而基于 Ag 掺杂剂的器件仍保持良好的光电特性。最后，我们证明了优化的 IOLED 与传统设备相比，电流效率提高了 40.3%。这项工作为在高温下操作的 IOLED 的应用提供了一种提高热稳定性和性能的新策略。