Perovskites are promising light emitters that can cover broad-range emissions over the entire visible spectrum. However, few studies have focused on uncommon wavebands, such as far-red emission of 700–750 nm that has broad applications in biology, horticulture lighting, optogenetics, etc. Here, a strategy is demonstrated to achieve high-performance far-red perovskite light-emitting diodes (PeLEDs) through antisolvent engineering. First, 1,3,5-tris(1-phenyl-1H-benzimidazole-2-yl) benzene (TPBi) is introduced into n-i-p perovskite matrix not only to passivate the defects but also to balance carrier mobility as well as adjust the energy level alignment between perovskite and the electron transport layer. The n-type TPBi can prevent hole carriers’ movements in perovskite light emitters and enhance electron injection. Furthermore, the incorporation of TPBi uplifts the Fermi energy level of perovskites by 0.32 eV as well as diminishes the conduction band offset between zinc oxide (ZnO) and the perovskite emitters, hence alleviating the accumulation of charges at the interface. Consequently, the PeLEDs with TPBi-modified perovskite emitters show an invariable far-red emission peak at around 735 nm with a champion external quantum efficiency of 14.22%. This work makes up the far-red emission of perovskite light-emitting devices and boosts latent capacity of PeLEDs for future application.

中文翻译：

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远红钙钛矿发光二极管中的平衡电荷载流子传输和缺陷钝化

钙钛矿是很有前途的发光体，可以覆盖整个可见光谱的宽范围发射。然而，很少有研究关注不常见的波段，例如在生物学、园艺照明、光遗传学等方面具有广泛应用的 700-750 nm 的远红光发射。在这里，展示了一种实现高性能远红钙钛矿的策略通过反溶剂工程制造发光二极管 (PeLED)。首先，将1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯(TPBi)引入nip钙钛矿基体中，不仅可以钝化缺陷，还可以平衡载流子迁移率并调节能量钙钛矿和电子传输层之间的水平排列。n 型 TPBi 可以防止空穴载流子在钙钛矿发光体中移动并增强电子注入。此外，TPBi的掺入将钙钛矿的费米能级提高了0.32 eV，并减少了氧化锌（ZnO）和钙钛矿发射极之间的导带偏移，从而减轻了界面处的电荷积累。因此，具有 TPBi 改性钙钛矿发射器的 PeLED 在 735 nm 左右显示出恒定的远红发射峰，外量子效率为 14.22%。这项工作弥补了钙钛矿发光器件的远红光发射，提高了 PeLED 的未来应用潜力。具有 TPBi 改性钙钛矿发射器的 PeLED 在 735 nm 左右显示出恒定的远红发射峰，外量子效率为 14.22%。这项工作弥补了钙钛矿发光器件的远红光发射，提高了 PeLED 的未来应用潜力。具有 TPBi 改性钙钛矿发射器的 PeLED 在 735 nm 左右显示出恒定的远红发射峰，外量子效率为 14.22%。这项工作弥补了钙钛矿发光器件的远红光发射，提高了 PeLED 的未来应用潜力。