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

Inorganic metal halide-based perovskites have tremendouspotentialfor 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 issueremains a challenge. Here, we report the use of a 3D printing techniqueto fabricate resin-perovskite color conversion layers to bridge thegap between material development and device applications. This notonly simplified the fabrication process but also significantly improvedthe performance of the device. By using an economic 3D printer, color-emittingperovskite nanocrystals (green, yellow, and red) were mixed with highlytransparent UV resin to obtain a thin color conversion layer. These3D-printed color conversion layers retained above 80% of their originalPLQY after 180 days of storage in ambient conditions, confirming theirexceptional stability. Furthermore, we stacked the printed color conversionlayers on top of the UV light-emitting diode chip, resulting in whitelights with tunable correlated color temperatures, high color renderingindexes up to 94, color coordinates of (0.32, 0.33) close to the standardneutral white light, and high luminous efficacy of radiation up to299 lm/W. As a result of this work, the adoption of solid-state lightingon a broader scale will be one step closer to reality.