Ligand‐Free CsPbBr₃ Perovskite Quantum Dots in Silica‐Aerogel Composites with Enhanced Stability for w‐LED and Display by Substituting Pb²⁺ with Pr³⁺ or Gd³⁺ Ions

Abstract

Colloidal all‐inorganic lead halide perovskite nanocrystals (LHP NCs) feature with tunable high‐efficiency photoluminescence from blue to red for optoelectronic applications but suffer from instability under water moisture, UV light illumination, high‐temperature shock, as well as oxygen erosion. Previous work to improve LHP NCs stability was mainly focused on either glass bulk sealed LHP quantum dots (QDs) with low quantum efficiency, or mesoporous silica matrixes confined LHP QDs with organic ligands still existing. Here, a facile, noncolloidal, ligand‐free LHP QDs growth with physical confinement is proposed by integrating the growth of perovskite QDs with the fabrication process of hydrophobic silica‐aerogel powders (SAPs). As a result, the as‐synthesized mono‐ and mixed‐cesium‐lead‐halide QDs @ SAPs composites show tunable photoluminescence from purple to deep red. Besides, the Pr3+ ions doped CsPbBr3 QDs @ SAPs composites exhibit moderate quantum efficiency, excellent stability under UV illumination, water moisture as well as temperature variation. Furthermore, performances of white LED device encapsulated Pr3+ doped composite with blue GaN chip and commercial red (Sr, Ca)AlSiN3:Eu2+ phosphor are evaluated. This work demonstrates a facile and general strategy for synthesizing high‐stable all‐inorganic cesium‐lead‐halide QDs for applications in white LED and display devices.

Epitaxial Growth of MgGa2O4/CsPbBr3 Heterostructure with Controlled Defect Tolerance for Dynamic Photoluminescence

“…The relative PL intensity of MgGa 2 O 4 /CsPbBr 3 increased significantly from 100% to 131.3% after soaking in H 2 O for 56 days due to the further surface defects passivation during immersion, as has been discovered in ligand-free CsPbBr 3 NCs. [42] However, the PL intensity for pure CsPbBr 3 NCs directly quenched to 14% after 21 days. Moreover, MgGa 2 O 4 /CsPbBr 3 heterostructure showed reversible PL intensity upon heating-cooling cycles in 10-100 °C (Figure S6c, Supporting Information).…”

Capping Ligand Engineering Enables Stable CsPbBr3 Perovskite Quantum Dots toward White-Light-Emitting Diodes

“…In recent years, inorganic (CsPbX 3 ; X = Cl, Br, and I) perovskite quantum dots (PeQDs) have been extensively studied and developed in the field of light-emitting devices, − benefiting from their tremendously excellent properties of long carrier diffusion lengths, , narrow and finely tunable emission spectra, high absorption coefficients, and facile band gap tunability. − Room-temperature synthesis of PeQDs, which do not have strict requirements on the synthesis environment, has shown great development potential, − compared with the high-temperature hot-injection method. − However, since the capping ligand is in a highly dynamic adsorption–desorption state, PeQDs are easily subject to stability issues triggered by moisture, heat, and polar solvents. − Furthermore, some defects will inevitably be introduced during synthesis, including halide ion vacancies, Pb ion vacancies, and Pb ion gaps, which serve as non-radiative recombination centers, quenching photogenerated excitons and photogenerated carriers, thus greatly reducing the luminous efficiency of inorganic perovskites. , …”

Ce3+–Eu2+ Co-doped BaCa13Mg2(SiO4)8 cyan phosphor—ultra-high energy transfer efficiency for white light emitting diodes

“…White light-emitting diodes (WLEDs) as a fourth-generation lighting source have the advantages of being green, long lifetime, pollution-free, and high luminous efficiency. 1–6 Commercially available WLEDs are mostly prepared by blue InGaN chips with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce). 7,8 However, the spectrum of the WLEDs created in that way has a significant red wavelength deficiency, leading to highly correlated color temperatures and a low color rendering index( R a ).…”