Band Alignment Engineering in ns² Electrons Doped Metal Halide Perovskites

Abstract

Luminescent metal halide perovskites (MHPs) open new avenues for highly efficient radiation detection. To challenge the state‐of‐art technology, fundamental understanding of factors controlling radiation light yield of MHP scintillators is urgent. Herein, a design method is established by simultaneously considering charge‐transfer and recombination efficiencies via band alignment engineering in doped MHPs materials, and this strategy is corroborated experimentally and computationally by applying it to the luminescence of ns2 electron (Sb3+, Bi3+, and Te4+) doped vacancy‐ordered double perovskite Cs2ZrCl6. Alloying Te4+ into Cs2ZrCl6 is optimized and significantly improves the scintillation performance, including a twofold increase in light yield and a threefold increase in detection limit over pristine Cs2ZrCl6, and high‐resolution X‐ray imaging with 20 μm for 2D and 0.2 mm for 3D imaging. It is believed that doping engineering in MHPs enabling band alignment method holds great potential for the development of next‐generation MHP scintillators.

Zn2+ Doping in Organic Manganese(II) Bromide Hybrid Scintillators toward Enhanced Light Yield for X‐Ray Imaging

“…Recently, luminescent metal halides are endowed with potentiality as promising scintillation materials by DOI: 10.1002/adom.202300330 virtue of their high charge-carrier mobilities, low trap density and low-cost solutionprocessability. [2] For instance, Rb 2 CuX 3 , (TBA)CuX 2 (TBA = tetrabutylammonium cation; X = Cl, Br), (C 38 H 34 P 2 )MnBr 4 , (ETP) 2 MnBr 4 (ETP = ethyltriphenylphosphonium), and TPP 2 MnBr 4 (TPP = tetraphenylphosphonium) in the form of single crystals, composite films or transparent glass or ceramics were studied with LY ranging from 17 000 to 91 000 photons MeV −1 . [3] In this respect, it opens a new avenue to explore novel metal halides with enhanced LY to meet the demands for radiation detection applications.…”

First-Principles Investigation on the Stability, Electronic Structure, and Exciton Self-Trapping Mechanism of 0D and 1D Cs3Cu2Cl5

“…Metal halides including lead halide perovskites and their derivatives have drawn broad interest in optoelectronic applications, including photovoltaics, light-emitting diodes, and photodetectors. − Particularly, the self-trapped exciton (STE)-based emission is widely observed in low-dimensional (2D to 0D) metal halides that feature a soft lattice and strong electron-phonon coupling. − In contrast to the narrow band photoluminescence (PL) from band-edge emission typically observed in rigid 3D materials, the STE emission associated with a transient local lattice distortion results in a broad PL band with the full width at half-maximum often greater than 60 nm and a large Stokes shift . Besides lead halides, low-dimensional Ge­(II), Sn­(II), Sb­(III), Bi­(III), In­(III), Ag­(I), and Cu­(I) halides with high PL quantum yield (PLQY) have also been reported. − Among them, copper halides have attracted particularly great interest in recent years because of the earth abundance and nontoxicity of the copper element, structural diversity, and impressive photophysical properties that are promising for commercial applications. − …”

Sn2+doping-induced large extra vibrational energy of an excited state for efficient blue emission in Cs2SnCl6:Bi

“…Recently, many lead-free metal halides have been explored, such as Cs 2 NaInCl 6 , Cs 2 AgInCl 6 , Cs 3 Bi 2 I 9 , Cs 3 Cu 2 I 5 and Cs 2 ZrCl 6 , owing to their excellent optoelectronic properties and stable structures. 17–23 Among them, Cs 2 SnCl 6 with its stable tetravalent cation is considered as a promising candidate for photoelectric applications. 24,25 The Cs 2 SnCl 6 crystal is derived from the three-dimensional CsSnCl 3 perovskite, which periodically removes half of the Sn atoms at the center of each [SnCl 6 ] 2− octahedron, forming a vacant-ordered double perovskite structure (space group Fm 3̄ m ).…”