Solid-State White Light-Emitting Diodes Based on 3D-Printed CsPbX₃-Resin Color Conversion Layers

Inorganic metal halide-based perovskites have tremendous potential for use in solid-state lighting due to their earth-abundant elements, solution processability, high photoluminescence quantum yield (PLQY), and tunable band gap energy and emission. However, the stability issue remains a challenge. Here, we report the use of a 3D printing technique to fabricate resin-perovskite color conversion layers to bridge the gap between material development and device applications. This not only simplified the fabrication process but also significantly improved the performance of the device. By using an economic 3D printer, color-emitting perovskite nanocrystals (green, yellow, and red) were mixed with highly transparent UV resin to obtain a thin color conversion layer. These 3D-printed color conversion layers retained above 80% of their original PLQY after 180 days of storage in ambient conditions, confirming their exceptional stability. Furthermore, we stacked the printed color conversion layers on top of the UV light-emitting diode chip, resulting in white lights with tunable correlated color temperatures, high color rendering indexes up to 94, color coordinates of (0.32, 0.33) close to the standard neutral white light, and high luminous efficacy of radiation up to 299 lm/W. As a result of this work, the adoption of solid-state lighting on a broader scale will be one step closer to reality.