Thermally Activated Delayed Fluorescent Scintillators Based on Mononuclear Copper(I) Halide Complexes for High‐Resolution X‐Ray Imaging

Abstract

non-destructive testing and medical theranostic applications. [1] Conventional scintillators containing heavy atoms (e.g., CsI:Tl, Bi 4 Ge 3 O 12 , PbWO 4 , YAlO 3 :Ce) have been commercially utilized in X-ray imaging, however, almost all of them relied on costly bulk crystals and were grown by the Czochralski method under harsh preparation conditions. [2] Recently, lead halide perovskite-based scintillators exhibited outstanding performance, but the self-absorption, hygroscopicity and elemental toxicity severely limit their practical applications. [3] Numerous attempts have been made to address these issues by developing lead-free perovskite analogs, trying to replace lead with other elements such as silver, [4] bismuth, [5] antimony, [6] manganese [7] and copper. [8] Lanthanide-doped inorganic oxide or fluoride nanoscintillators [9] and organic scintillators [10] have also been reported. Despite enormous efforts, the development of novel scintillators with low cost, high performance, and good solution processability remains a formidable challenge.The general scintillation process mainly consists of three stages: conversion, transport, and luminescence. [11] Under X-ray irradiation, electrons and holes were mainly generated in the inner layers of atoms through the photoelectric effect and Compton scattering. Subsequently, the cascaded secondary electrons migrated to the conduction band and valence band or generated low-energy excitations for luminescence. In this sense, most of the light emission in scintillators was excited by electronic transitions caused by electron impact, which was similar to the electroluminescence in some respects. [12] A large number of triplet excitons and singlet excitons can be generated in a ratio of 3:1. Thus, we can naturally think that those molecules that have been successfully utilized in organic light-emitting diodes (OLEDs) are likely to be good candidate for X-ray excited luminescence (XEL) materials. Yang and coworkers reported three organic thermally activated delayed fluorescence (TADF) scintillators for high-resolution X-ray imaging, which demonstrated the importance of harvesting both singlet and triplet excitons for efficient X-ray scintillation. [13] Although these organic scintillators showed high relative light yields, in fact, their XEL intensity Scintillators have attracted tremendous attention due to their great potential in radiation detection, industrial non-destructive testing, and medical theranostic applications. Thermally activated delayed fluorescence (TADF) based scintillators can simultaneously harvest radiation-induced singlet and triplet excitons for high-efficient X-ray excited luminescence. However, pure organic TADF materials composed of light elements exhibit low X-ray absorption coefficients, resulting in relatively weak X-ray excited luminescence. Herein, a series of novel high-performance X-ray scintillators based on TADF mononuclear Cu(I)-halide complexes are successfully developed. Together with high X-ray absorption coefficient of heavy h...

Rational design and synthesis of scintillating lanthanide coordination polymers for highly efficient X-ray imaging

“…The X-ray imaging was conducted using an home-made imaging system constructed by an Au target X-ray tube (Amptek Mini-X2, tube voltage 50 kV) and a digital camera (Nikon 850D). 33 All of the X-ray excited luminescence spectra and X-ray imaging were conducted in a lead box. The X-ray attenuation efficiency, relative light yields and modulation transfer function (MTF) measurements were conducted according to the reported methods.…”

“…The X-ray attenuation efficiency, relative light yields and modulation transfer function (MTF) measurements were conducted according to the reported methods. 33,34…”

Chirality–Racemization Strategy Toward Copper (I) Iodide Hybrid Single‐Crystalline Scintillators for X‐Ray Detection and Imaging Applications

“…The radioluminescence processes are systematically depicted in Figure S17 (Supporting Information) when exposed to X-ray irradiation condition. [66][67][68][69][70] According to the photoelectric effect and Compton scattering effect, the highenergy photon interacts with the lattice atoms of the material and exciting electrons in the inner shell transit to high energetic levels. [71] The Auger process and electron scattering produce a large number of secondary electrons that dissipate the energy of carrier.…”

Chiral hybrid manganese(ii) halide clusters with circularly polarized luminescence for X-ray imaging

“…Due to the advantages of eco-friendliness, low cost and high luminescence quantum efficiency, manganese(II) halides can be used for promising and efficient luminescent materials. [23][24][25][26] Their luminescence mechanism comes from the d orbital electron transition in the crystal field. [27][28][29] At present, manganesebased hybrid halides are widely used in light-emitting diodes, solar cells, photoelectric detection and other fields.…”

“…[27][28][29] At present, manganesebased hybrid halides are widely used in light-emitting diodes, solar cells, photoelectric detection and other fields. 26 However, the discovery of chiral hybrid manganese halides is very scarce, and in particular there is no report on chiral manganese(II) halide clusters. Therefore, the development of novel chiral manganese(II) halide clusters is crucial for the further study of manganese-based halides.…”