Research on all-inorganic perovskite quantum dots (PQDs) has been actively pursued due to their unique and excellent optoelectronic properties. In particular, blue light-emitting diodes (LEDs) based on PQDs have been thoroughly explored because their ...
Research on all-inorganic perovskite quantum dots (PQDs) has been actively pursued due to their unique and excellent optoelectronic properties. In particular, blue light-emitting diodes (LEDs) based on PQDs have been thoroughly explored because their efficiency is substantially lower than those of the red and green perovskite-based LEDs. However, blue-emitting PQDs still face numerous obstacles, such as phase separation, halide vacancies, and surface defects, eventually leading to poor emission stability and low external quantum efficiency. Here, we successfully synthesized highly efficient and stable blue-emitting CsPbBr3 QDs with a uniform size distribution of 4.6±0.9 nm by introducing trioctylphosphine (TOP) as a surface-capping ligand. The TOP-capped CsPbBr3 QDs showed a near-unity photoluminescence quantum yield of 97.9%. The phosphine in TOP effectively passivates the surface of the small-size CsPbBr₃ QDs, consequently improving their emission efficiency and long-term stability. Blue LEDs fabricated by the TOP-treated CsPbBr3 QDs exhibited an improved luminance of 328 cd/m2 and exceptional color stability, maintaining longer emission stability than the pristine QDs.