High‐Speed Fabrication of All‐Inkjet‐Printed Organometallic Halide Perovskite Light‐Emitting Diodes on Elastic Substrates

Abstract Halide perovskites have great potential for use in high‐performance light‐emitting diodes (LEDs) and displays. Here, a perovskite LEDs (PeLEDs) fabricated directly on an elastomer substrate, in which every single layer in the device from bottom anode to top cathode is patterned solely using a highly scalable inkjet printing process, is reported. Compared to PeLEDs made using conventional microfabrication processes, the printing process significantly shortens the fabrication time by at least tenfold (from over 5 h to less than 25 min). The all‐printed PeLEDs have a novel 4‐layer structure (bottom electrode, perovskite emissive layer, buffer layer, top electrode) without separate electron or hole transporting layers. For flexible PeLEDs printed directly in ambient conditions, a turn‐on voltage, maximum luminance intensity, and maximum current efficiency of 3.46 V, 10227 cd m⁻², and 2.01 cd A⁻¹, respectively, is achieved. The devices also exhibit excellent robustness and stability even when bent to a curvature radius of 2.5 mm. The reported device structure and fabrication processes can enable high‐performance flexible PeLEDs to be manufactured over a larger area at extremely low cost and fast speed, which can facilitate the adoption of the promising PeLED technology in the emerging foldable displays, smart wearables, and many other applications.