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Improving Lead‐Free Double Perovskite Cs 2 NaBiCl 6 Nanocrystal Optical Properties via Ion Doping
Author(s) -
Yao MingMing,
Wang Li,
Yao JiSong,
Wang KunHua,
Chen Chen,
Zhu BaiSheng,
Yang JunNan,
Wang JingJing,
Xu WeiPing,
Zhang Qun,
Yao HongBin
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901919
Subject(s) - materials science , photoluminescence , quantum yield , nanocrystal , doping , perovskite (structure) , dopant , halide , ion , quantum dot , analytical chemistry (journal) , nanotechnology , optoelectronics , crystallography , inorganic chemistry , optics , chemistry , fluorescence , physics , organic chemistry , chromatography
Abstract The exploration of lead‐free halide perovskite nanocrystals (NCs) with intriguing optical properties is highly desirable owing to the toxicity and instability of lead halide perovskite NCs. Here, a new kind of uniform lead‐free double perovskite Cs 2 NaBiCl 6 NCs are reported as versatile hosts to accommodate ionic dopants for improving optical properties especially the photoluminescence (PL). In contrast to the low deep‐blue PL with a quantum yield of only 1.7% of the as‐synthesized pristine Cs 2 NaBiCl 6 NCs, the PL of the Cs 2 NaBiCl 6 NCs can be impressively regulated and enhanced via doping Ag + , Mn 2+ , or Eu 3+ ions in the double perovskite lattices. The femtosecond time‐resolved transient absorption spectroscopy is adopted to unravel the PL enhancement mechanism of the ion doping in the Cs 2 NaBiCl 6 NCs. For the Ag + ‐doping, the excitonic absorption energy of the Cs 2 NaBiCl 6 NCs can be tuned from 3.82 to 3.48 eV with the significant improvement of the PL quantum yield (PLQY) from 1.7% to 20%. The Mn 2+ ‐doped Cs 2 NaBiCl 6 NCs show broad orange–red emission peak centered at 585 nm with a PLQY of 3%, owing to the 4 T 1 → 6 A 1 transition of octahedrally coordinated Mn 2+ . Eu 3+ ‐doped Cs 2 NaBiCl 6 NCs are endowed with strong Eu 3+5 D 0 → 7 F J ( J = 1, 2) orange–red emission at 591 and 615 nm.