Ionic Doping of CsPbI₃ Perovskite Nanocrystals Improves Luminescence and Stability in Patterned Large-Area Light-Emitting Diodes

With high quantum efficiency, unique bandgap, and narrow emission band, all-inorganic CsPbI₃ halide perovskite nanocrystals have been widely acknowledged as competitive candidates for pure red light-emitting diodes (LEDs). However, the large-scale manufacturing and stability of CsPbI₃ perovskites are the main obstacles for practical LEDs. In this work, by Mg²⁺/Yb³⁺ codoping, we successfully improve the luminous intensity (192%) in an ambient environment. What is more, these ionic doped CsPbI₃ perovskite nanocrystals are thermally stable at 120 °C. Based on these perovskite nanocrystals, we also fabricate large-scale patterned LEDs (25.4 × 25.4 mm). At a bias voltage of 6 V, the fabricated LEDs exhibit a luminance of 749 cd m^-2. At a current density of 6.4 mA cm^-2, the fabricated LEDs achieved an external quantum efficiency of 10.9%. This result is expected to fuel the rapid growth of large-area pure red LEDs.