Co-regulation strategy dominated by double short molecules permitting the regrowth of quantum dots for efficient deep-blue perovskite light-emitting diodes

Recently, blue perovskite quantum dots (PeQDs) have garnered considerable attention for use in full-color optoelectronic displays. However, the large specific surface area caused by the small particle size of blue PeQDs results in high defect state density, which severely limits their optical pursuit. To address this issue, a co-regulation strategy using double short-chain molecules of tetraoctylammonium fluoride and tetraethylammonium perfluorooctanesulfonate is proposed to enhance the regrowth of blue CsxRb1−xPb(ClyBr1−y)3 PeQDs. Long-chain insulated oleylamine and oleic acid ligands, which restrict the growth of PeQDs, are substantially replaced using short-chain ligands with higher adsorption energy. This replacement promotes PeQDs to regrow considerably from ∼8 to ∼18 nm, and the defect-state density decreases by 3–5 times. Consequently, highly efficient blue PeQDs with a photoluminescent quantum yield of unity are obtained. Moreover, the PeQDs exhibit lower insulating ligand density and improved charge injection property. As a result, the synthesized deep-blue PeQD light-emitting diodes (PeQLEDs) exhibit a maximum external quantum efficiency of 5.7% at the CIE coordinate of (0.148, 0.032). According to the International Telecommunication Union Radiocommunication Sector television standard (Rec. 2100), the obtained PeQLEDs are state-of-the-art among colloidal deep-blue PeQDs. This study provides a novel strategy to improve the optical performance of deep-blue PeQLEDs and paves the way for developing high-end wide color-gamut displays. [Display omitted] •This work promotes the crystal growth of perovskite quantum dots from 8 to 18 nm, with enhanced crystallinity and stability.•The defect state density is suppressed 3–5 times to achieve near-unity photoluminescence quantum yield of deep-blue emission.•The replacement of surface long-chain insulating ligands with short-chain ligands improves charge injection performance.•Patterned aerosol inkjet printing based on regrowth perovskite quantum dots with well dispersion stability is realized.•High color purity and efficient deep-blue colloidal perovskite quantum dots light-emitting diode is achieved.