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Quantum Dots of [Na 4 Cs 6 PbBr 4 ] 8+ , Water Stable in Zeolite X, Luminesce Sharply in the Green
Author(s) -
Kim Joon Young,
Shim Kyu In,
Han Jeong Woo,
Joo Jin,
Heo Nam Ho,
Seff Karl
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202001868
Subject(s) - photoluminescence , materials science , zeolite , luminescence , nanocrystal , ion , quantum yield , quantum dot , perovskite (structure) , crystal (programming language) , mesoporous material , analytical chemistry (journal) , crystallography , nanotechnology , chemistry , optoelectronics , catalysis , physics , optics , fluorescence , biochemistry , programming language , organic chemistry , chromatography , computer science
Nanocrystals (NCs) of CsPbX 3 , X = Cl, Br, or I, have excellent photoluminescent properties: high quantum yield, tunable emission wavelengths (410−700 nm), and narrow emission band widths. CsPbBr 3 NCs show high promise as a green‐emitting material for use in wide color gamut displays. CsPbBr 3 NCs have, however, not been commercialized because they are sensitive to moisture and heat. To avoid these problems, this work attempts to introduce CsPbBr 3 into five zeolites. The zeolite X product, Pb,Br,H,Cs,Na−X, shows superior stability toward moisture, maintaining its initial luminescence properties after being under water for more than a month. Its structure, determined using single‐crystal X‐ray crystallography, shows that quantum dots (QDs) of [Na 4 Cs 6 PbBr 4 ] 8+ (not of CsPbBr 3 ) have formed. They are tetrahedral PbBr 4 2− ions (Pb−Br = 3.091(11) Å) surrounded by Na + and Cs + ions. Each fills the zeolite's supercage with its Pb 2+ ion precisely at the center, a position of high symmetry. The peaks in the emission spectra of Pb,Br,H,Cs,Na−X and the CsPbBr 3 NCs are both at about 520 nm. The FWHM of Pb,Br,H,Cs,Na−X, however, is narrower than any previously reported for any of the CsPbBr 3 NCs, and for zeolite Y and the various mesoporous materials treated with CsPbBr 3 .