Tailoring Substitutional Sites for Efficient Lanthanide Doping in Lead-Free Perovskite Nanocrystals with Enhanced Near-Infrared Photoluminescence.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40214125.
- Also identified by DOI 10.1021/acsnano.5c00487 and PMC identifier 12020422.
- Licence recorded as CC BY.
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Abstract
The incorporation of rare earth lanthanide ions (Ln<sup>3+</sup>) into lead-free halide perovskite nanocrystals (NCs) is an effective and promising strategy to expand their optical, magnetic, and electrochemical properties. Herein, we designed and synthesized various Ln<sup>3+</sup> (including Yb<sup>3+</sup>, Er<sup>3+</sup>, and Nd<sup>3+</sup>), doped Sb<sup>3+</sup>- or Bi<sup>3+</sup>-based and Sb<sup>3+</sup>/Bi<sup>3+</sup> alloyed lead-free perovskite NCs, including vacancy-induced perovskite (A<sub>3</sub>B(III)<sub>2</sub>X<sub>9</sub>), double perovskite (A<sub>2</sub>B(I)B (III)X<sub>6</sub>), and layered-double perovskite (A<sub>4</sub>B(II)B(III)<sub>2</sub>X<sub>12</sub>) NCs with different energy transfer pathways to study the Ln<sup>3+</sup> dopant photoluminescence (PL). While a small size mismatch between dopant ions and host substitutional sites are critical for efficient doping of many first-row transitional metal ion doped metal chalcogenides, surprisingly, the Ln<sup>3+</sup> ions, including the large Nd<sup>3+</sup> ions (112 pm), prefer smaller isovalent Sb(III) octahedral (O<sub>h</sub>) sites (90 pm) instead of Bi(III) O<sub>h</sub> sites (117 pm) in these lead-free perovskite NCs. Significantly, similar substitutional site-dependent Ln<sup>3+</sup> doping efficiencies were obtained across all three different perovskite host lattices, despite differences in host-to-dopant energy transfer mechanisms, which can provide strong evidence of the preferred Sb<sup>3+</sup> substitutional sites for lanthanide dopants in these lead-free perovskite lattices. The efficient Ln<sup>3+</sup> doping in Sb<sup>3+</sup>-rich perovskite NCs leads to enhanced Ln<sup>3+</sup> ion PL of the doped NCs. The preference of smaller Sb (III) over Bi(III) substitutional sites for Ln<sup>3+</sup> dopants is attributed to the relatively high polarizabilities of lanthanide ions and the smaller cationic sites inside [SbX<sub>6</sub>]<sup>3-</sup> compared with [BiX<sub>6</sub>]<sup>3-</sup> octahedra. This study provides a fundamental understanding of Ln<sup>3+</sup> doping behavior in lead-free perovskite NCs and opportunities for designing efficient Ln<sup>3+</sup>-doped functional materials by tuning the microenvironment of the host lattice for enhanced properties.