Nucleation-controlled growth of ultra-small perovskite quantum dots for bright blue light-emitting diodes

Creating highly efficient and stable pure blue (≈470 nm) perovskite quantum dots (PQDs) remains a considerable challenge. Here, we report an effective synthesis strategy of ultrasmall (≈3.8 nm) blue CsPbBr3 QDs by using PbBr2 clusters as nucleation sites, which then react with Cs-oleate at relatively low temperatures. The emission wavelength of CsPbBr3 QDs ranging from 460 nm to 497 nm could be facilely tuned by the amount of Cs-oleate or reaction temperature. The optimum PL QY of the blue CsPbBr3 QDs reaches as high as above 64%. The CsPbBr3 QDs are further coated with superhydrophobic fluorinated silica and successfully applied in blue light-emitting diodes (LEDs). The nucleation-controlled growth of ultra-small blue PQDs provides a new synthesis strategy for efficient and stable blue PQDs.