Sb‐Doped Cs₃TbCl₆ Nanocrystals for Highly Efficient Narrow‐Band Green Emission and X‐Ray Imaging

Abstract

Metal halide nanocrystals (NCs) with high photoluminescence quantum yield (PLQY) are desirable for lighting, display and X‐ray detection. Herein, we are committed to designing the novel lanthanide‐based halide NCs, optimizing the optical and scintillating properties, so as to unravel the PL origin, exciton dynamics and optoelectronic applications. Sb‐doped zero‐dimensional (0D) Cs3TbCl6 NCs exhibit a green emission with a narrow full width of half maximum of 8.6 nm and the best PLQY of 48.1% is about three times higher than that of undoped NCs. Experiments and theoretical calculations indicate that 0D crystalline and electronic structures make the exciton highly localized on [TbCl6]3− octahedron, which boosts the Cl−‐Tb3+ charge transfer process, thus resulting in bright Tb3+ emission. More importantly, the introduction of Sb3+ not only facilitates the photon absorption transition, but also builds an effective thermally boosting energy transfer channel assisted by [SbCl6]3−‐induced self‐trapped state, which are responsible for the PL enhancement. The high luminescence efficiency and negligible self‐absorption of Cs3TbCl6: Sb nanoscintillator enable a more sensitive X‐ray detection response compared with undoped sample. The study opens a new perspective to deeply understand the excited state dynamics of metal halide NCs, which helps to design high‐performance luminescent lanthanide‐based nanomaterials.This article is protected by copyright. All rights reserved

Lanthanide/Bismuth-Codoped Lead-Free Halide Double Perovskite Nanocrystals with Upconversion and Short-Wave Infrared Luminescence

“…For SWIR PL of Yb/ Er/Bi-codoped Cs 2 NaInCl 6 NCs, under ultraviolet irradiation, the S → P transition of Bi 3+ in the [BiCl 6 ] 3− octahedron is activated, which causes the carriers to be in the excited state, implying that there should be an energy-transfer process from the [BiCl 6 ] 3− -induced trap state to the [ErCl 6 ] 3− octahedron. This is a typical photophysical process in inorganic halide DPs containing both ns 2 electron dopants and lanthanides that has been reported, 12,13,22,24,41,42 and it is reasonable to deduce that the [BiCl 6 ] 3− -induced trap state is an STE state.…”

“…The Cs 2 NaInCl 6 :Yb/Er/Bi NCs have a long SWIR PL lifetime of 20.34 ms as shown in Figure f. The typical long-lived single-exponential behavior of the NCs is the typical characteristic of f–f transitions of lanthanide ions The SWIR PL at 1540 nm arises from the Laporte forbidden 4 I 13/2 → 2 I 15/2 transition of the Er 3+ .…”

“…The typical long-lived single-exponential behavior of the NCs is the typical characteristic of f−f transitions of lanthanide ions. 42,43 The SWIR PL at 1540 nm arises from the Laporte forbidden 4 I 13/2 → 2 I 15/2 transition of the Er 3+ . 44 However, the SWIR PL lifetime of Cs 2 NaInCl 6 :Yb/Er NCs has not been measured due to their extremely weak SWIR PL.…”

Sb3+–doped 0D Cs3GdCl6 microcrystals with a near-unity photoluminescence quantum yield and high thermal quenching resistance for light-emitting application

“…with low phonon energies and suitable crystallographic sites, are promising candidates as efficient host materials for ns 2 -electron ion doping to achieve the desired properties. 32–37 However, synthesizing Cs 3 RECl 6 crystals through a wet chemical route at low temperatures remains a challenge, because rare-earth halides tend to crystallize into the hydrated phase in solution, 38–40 which may quench the PL due to the presence of the high-energy vibrational –OH group. In this regard, it is of fundamental significance to develop a new approach for the wet-chemical synthesis of ns 2 -electron ion doped Cs 3 RECl 6 crystals to facilitate efficient and tunable PL coupled with excellent thermal quenching resistance for device engineering in practical applications.…”

“…with low phonon energies and suitable crystallographic sites, are promising candidates as efficient host materials for ns 2 -electron ion doping to achieve the desired properties. [32][33][34][35][36][37] However, synthesizing Cs 3 RECl 6 crystals through a wet…”