Photon recycling (PR), reabsorption and reemission of photons, can randomize the propagation direction of photons trapped in the waveguide mode and potentially increase the outcoupling efficiency of perovskite light-emitting diodes (PeLEDs). However, the contribution of PR in PeLEDs has not been experimentally quantified in real device structures. Here, we show that, with the PR effect, the external quantum efficiency (EQE) of PeLEDs remains above 15% with extraordinary thick perovskite layers up to 2200 nm, which is much higher than the outcoupling efficiency (4.3%) of the thick emissive layer device with an emission zone near the TPBi layer without PR. We designed monolithic device structures to experimentally quantify the PR contribution under device working conditions and reveal that the PR can contribute 2.4%–40.4% of the total emission in PeLEDs depending on film thickness. This work provides an important way of manipulation and quantification of PR contribution in perovskite optoelectronic devices.

中文翻译：

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利用增强的光子循环克服钙钛矿发光二极管的耦合输出限制

光子循环 (PR)、光子的重吸收和再发射可以使被困在波导模式中的光子的传播方向随机化，并有可能提高钙钛矿发光二极管 (PeLED) 的耦合效率。然而，PR 在 PeLED 中的贡献尚未在实际器件结构中通过实验量化。在这里，我们表明，在 PR 效应下，PeLED 的外部量子效率 (EQE) 保持在 15% 以上，钙钛矿层的厚度高达 2200 nm，远高于厚发光材料的外耦合效率 (4.3%)。层器件，在 TPBi 层附近有一个发射区，没有 PR。我们设计了单片器件结构来实验量化器件工作条件下的 PR 贡献，并表明 PR 可以贡献 2.4%–40。PeLED 总发射量的 4%，具体取决于薄膜厚度。这项工作提供了一种重要的方法来操纵和量化钙钛矿光电器件中 PR 的贡献。