High-performance near-infrared circularly polarized electroluminescence with an emission peak beyond 900 nm

Near-infrared spin-light-emitting diodes (NIR-Spin-LEDs), which generate circularly polarized light, offer opportunities for applications such as biomedicine. However, the longest reported emission wavelength of NIR-Spin-LEDs remains limited to 782 nm, making spin-polarized electroluminescence beyond 800 nm challenging. Here we show NIR-Spin-LEDs based on a mixed-dimensional tin-based perovskite heterostructure incorporating chiral R/S-α-methylbenzylammonium (R/S-MBA⁺) spacer cations. The low-dimensional phases induced by R/S-MBA⁺ provide chiroptical activity, while three-dimensional FA_0.9Cs_0.1SnI₃ domains serve as the near-infrared emissive centers. Controlled crystallization produces a cypress-leaf-like morphology that promotes carrier confinement and improves charge-injection balance. The resulting devices exhibit electroluminescence peaking at 905 nm, with an external quantum efficiency of 7.8% and a maximum electroluminescence dissymmetry factor (g_EL) of 5.5 × 10^-2. This work extends spin-polarized electroluminescence into the deep near-infrared region and provides a strategy for developing lead-free NIR-Spin-LEDs.