Efficient Thermally Evaporated Near-Infrared Perovskite Light-Emitting Diodes via Phase Regulation

• α-phase formamidinium lead triiodide (FAPbI3) was prepared based on triple-source co-evaporation. • A partial Cs-doping in the FAPbI3 can help with the suppression of the non-radiative recombination, elimination of the metallic Pb, improvement of spatial confinement. • Near-infrared perovskite light-emitting diodes (NIR-PeLEDs) based on triple-source co-evaporated FACsPbI3 thin films achieved a maximum external quantum efficiency of 10.25%, which was around 6 times higher than that of FAPbI3-based NIR-PeLEDs. • The work demonstrates a reliable and effective strategy to achieve α-FAPbI3 via thermal evaporation, paving the way toward highly efficient perovskite optoelectronic devices for future commercialization.