Recent advances in perovskite-sensitized photon upconversion via triplet-triplet annihilation (TTA) in rubrene have yielded several unanswered questions about the underlying mechanism and processes occurring at the interface. In particular, the near-infrared perovskite emission is not significantly quenched and a rapid reversible "photobleach" of the upconverted emission can be observed under fairly low excitation densities of 3.2 mW/cm2. In this contribution, we investigate the perovskite/rubrene interface in more detail and conclude that noncovalent interactions between the organic layer and the perovskite result in surface trap passivation. In addition, band bending results in a space charge region at the perovskite/rubrene interface, which "precharges" the rubrene with holes. Upon initial illumination, electrons can rapidly transfer to the excited triplet state of rubrene, followed by efficient TTA upconversion. As the device is continuously illuminated, the existing holes are consumed and a new equilibrium is reached, resulting in the previously investigated steady-state upconversion efficiency.

中文翻译：

---

预充电光子上转换：溶液处理的钙钛矿上转换装置中的界面相互作用。

通过红三烯中三重态-三重态an灭（TTA）的钙钛矿敏化光子上转换的最新进展产生了一些关于在界面处发生的潜在机理和过程的未解决的问题。特别是，近红外钙钛矿的发射没有被显着淬灭，并且在3.2 mW / cm2的相当低的激发密度下，可以观察到上转换发射的快速可逆的“光漂白”。在这项贡献中，我们将更详细地研究钙钛矿/钌界面，并得出结论，有机层与钙钛矿之间的非共价相互作用会导致表面陷阱钝化。另外，带弯曲在钙钛矿/钌界面处产生空间电荷区域，该空间电荷区域将红荧烯“预填充”有孔。初始照明时 电子可以迅速转移到红荧烯的激发三重态，然后进行有效的TTA上转换。随着设备的持续照明，现有的孔被消耗，并且达到了新的平衡，从而导致了先前研究的稳态上转换效率。