Alkoxysilane‐Treated SnO₂ Interlayer for Energy Band Alignment of SnO₂ Electron Injection Layer in Inverted Perovskite Light‐Emitting Diodes

Abstract Efficient inverted perovskite light‐emitting diodes (PeLEDs) are demonstrated by the introduction of tetraethyl orthosilicate (TEOS)‐incorporated tin oxide (SnO₂) interlayer between the SnO₂ electron injection layer and the perovskite emission layer. The TEOS incorporation into the SnO₂ solution spontaneously converts it to a SiO₂–SnO₂ composite colloidal solution with a wide band gap, thermal stability, transparency, and chemical stability toward perovskite. The TEOS‐incorporated SnO₂ interlayer effectively restricts the charge transfer from perovskite into SnO₂ and promotes electron injection from SnO₂ into perovskite due to the shift toward favorable energy band alignment. In addition, the TEOS‐treated interlayer balances the electron injection rate and the hole injection rate, thereby facilitating radiative recombination of the charge carriers injected into perovskite. As a result, the inverted PeLEDs exhibit significantly improved performance of 33 996 cd m⁻² luminance, 9.99% of external quantum efficiency, and 44.83 cd A⁻¹ of current efficiency.