Optimization of CsPb(Br/I) 3 Perovskite Nanocrystal Embedded Borosilicate Glasses as a Robust Red Color Converter

ABSTRACT Despite recent progress in CsPbX 3 (X = Cl, Br, I) perovskite nanocrystals (PNCs) for color converters, the luminance of pure red LEDs with the Rec. 2020 standard Commission Internationale de l'Eclairage (CIE) 1931 color coordinates of (0.708, 0.292) has yet to meet the requirement for outdoor display. The present study demonstrates an effective method for improving the photo‐luminescence quantum yield (PLQY) of the pure red emission of CsPb(Br/I) 3 PNCs embedded in borosilicate glasses, to provide a robust color converter for ultra‐high definition (UHD) display applications. Improvement in the PLQY in the range 620–700 nm was achieved by changing the Br/I content ratio in the perovskite nanocrystals and optimizing the heat treatment condition, resulting in a PLQY of up to 80.5%. Spectroscopic changes as well as structural modification of the glasses with the halide ratio and heat treatment conditions were studied to elucidate the formation of CsPb(Br/I) 3 PNCs and their enhanced PLQY. The optimized red PNC embedded glass (PNEG) was fabricated as a wLED with a CsPbBr 3 PNEG as a green color converter and 450 nm InGaN blue LED chip to demonstrate its practical feasibility for display applications, with a wide color gamut reaching ∼140% of the National Television Standard Committee (NTSC) defined area.