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The high‐profile candidacy of low‐dimensional metal‐halide single crystals as promising light emitters originates from the intriguing emission properties (e.g., extremely broad luminescence spectra, large Stokes shift, high color rendition), which have enabled the recent great achievements on their application in lighting, artificial illumination, and scintillators. Among the family of low‐dimensional metal‐halide single crystals, zero‐dimensional (0D) materials have been featured in the lowest dimensionality, and as a consequence, strongest quantum confinement, softest lattice, and strongest electron–phonon coupling have been further translated into near‐unity photoluminescence (PL) efficiency with broadband emission. However, as far as it is known, 0D structures are significantly underexplored. Herein, an overview is provided on recent advances of 0D metal‐halide single crystals, with a focus on comprehensive understanding and insightful perspectives behind the photophysical mechanism. Additionally, the challenges and future opportunities currently faced by 0D bulk metal halides are discussed in order to provide a roadmap for the future development of novel materials with versatile optical properties suited for practical applications. [ABSTRACT FROM AUTHOR]

LiCaAlF 6 single crystals doped with different Eu concentrations varied from 1 at% to 5 at%, and LiCaAlF 6 :Eu single crystals co-doped with 3 at%Cu+, 2 at%Mg2+, 2 at%Ba2+ were grown by the Bridgman method in non-vacuum atmosphere. Their optical and scintillation performances were studied. The optimal scintillation efficiency was achieved in the LiCaAlF 6 :Eu single crystals with Eu concentrations between 2 and 2.5 at%. The influences of Cu+, Mg2+ and Ba2+ co-doping on optical properties, scintillation yield, scintillation decay and defect structures were studied. It was found that the Cu+ co-doping can improve the scintillation efficiency. The Mg2+ and Ba2+ co-doping have negligible effects on light yield. • Bridgman method in non-vacuum atmosphere were used to grow LiCaAlF 6 :Eu crystals. • The optimal scintillation efficiency obtained between 2 and 2.5 at%Eu concentration. • The Eu–Cu co-doping improve the scintillation efficiency than Eu doped LiCaAlF 6. • The Eu–Cu co-doping changed the defect structure than Eu doped LiCaAlF 6. [ABSTRACT FROM AUTHOR]

Europium doped strontium iodide (SrI 2 :Eu 2 +) is one of the cutting-edge halide scintillators for gamma-ray spectroscopy applications due to its low radioactive background, ultrahigh light yield (70,000–100,000 photons/MeV), and excellent gamma-ray energy resolution (2.6%–3% at 662 keV). In this work, we report an improvement in the scintillation characteristics of SrI 2 :Eu 2 + single crystals via tetravalent ion codoping, namely Zr 4 +. High quality SrI 2 :Eu 2 + single crystals codoped with 0, 0.05, 0.1, and 0.2 at.% Zr 4 + were grown by the Multi-ampoule Bridgman method. All of the as-grown crystals are transparent, crack-and inclusion-free. They have high optical quality with a transmittance of over 70%. The effects of Zr 4 + codoping on spectral properties and decay kinetics of SrI 2 :Eu 2 + under optical, and x- and gamma-ray excitation are studied. An enhancement of gamma-ray spectroscopic resolution from 2.8 to 2.5% at 662 keV and 5.4 to 5% at 122 keV is achieved upon Zr 4 + codoping with a slightly enhanced light yield of 95,000 photons/MeV. [ABSTRACT FROM AUTHOR]

Single crystal growth of undope CaCl 2 , CaBr 2 and CaI 2 was performed by Bridgman–Stockbarger (BS) method. Investigations of their crystal phases, luminescence and scintillation properties such light yield, energy resolution decay time were performed. In addition, linearity of gamma-ray response in 32–1275 keV range were also evaluated. The light output of 106,000 photon/MeV, energy resolution of 3.2%@662 keV, and scintillation decay time of 834 ns (84%) 1460 ns (16%) were observed. Luminescence properties of CaBr 2 also firstly reported. [ABSTRACT FROM AUTHOR]