Transparent Medium Embedded with CdS Quantum Dots for X‐Ray Imaging

Abstract

Herein, the performance of scintillator is the critical key to the X-ray imaging quality and accounts for the operation cost fundamentally.CsI: Tl and Bi 4 Ge 3 O 12 (BGO) have been employed successfully to commercial X-ray detectors [16,17] for their outstanding light yield with high spatial energy resolution (8-10 lp mm −1 ) and strong mechanical properties. [18] Although commercial scintillator as CsI: Tl possesses many advantages, a fatal drawback of CsI: Tl is the humid sensitivity. [19] When CsI: Tl is exposed to humid air, the absorbed water molecules affect the crystal structure, which leads to the declination of light yield performance of the corresponding scintillator and further deteriorates the X-ray imaging capacity of the detector. [13] In addition, the complex preparation process and long growth period of single crystal scintillator materials as BGO also challenges their practical application. [22] Notably, the halide perovskites, including single crystals, [20][21][22] wafer, [23][24][25] film, [26][27][28] crystallites, [29][30][31] exhibit compelling X-ray absorption and intense radiation luminescence (RL). Researchers devote their great enthusiasm to develop record-breaking detection limit and fast light decay for rendering the halide perovskites promi sing semiconductors in X-ray detection and imaging. [32] Successively progress has been achieved, nevertheless, issues that obstructs the application of halide perovskites in terms of their long-term instability, especially the photo-stability, moisture resistance, and thermal stability, has not been well addressed so far. [17,33,34] Hence, the exploration of scintillators that are easily synthesized, robust stable in ambient environment, and endurable for long-term operation is a persistent intriguing focus both for fundamental science and practical application.In this work, the in situ growth of CdS quantum dots (QDs) inside a robust amorphous matrix is realized by means of a facile heat treatment procedure, which presents an excellent RL performance under X-ray irradiation. Moreover, the uniform distribution of the precipitated CdS QDs embedded within the matrix endows a high transparency and homogeneous RL output. Herein, the as-explored CdS QDs glass-ceramic (GC) scintillator possesses a decent stable performance under an irradiation dose reaches 1 mGy air s −1 with a recorded spatial resolution of 10 lp mm −1 . Furthermore, it is demonstrated Scintillators, converting the absorbed high-energy X-ray photons into to visible ones, have been used in fields as medical diagnostics, radiation dosimetry, and security inspection. Commercial bulk scintillators generally suffer from time-consuming production, high-cost operation, and deteriorated performance especially exposed to humidity. Here, in situ precipitated CdS quantum dots (QDs) within the transparent glass matrix are achieved feasibly. The CdS QDs glass-ceramic (GC) is explored to be a superior scintillator with an outstanding weather resistance. A profound radioluminescence behavior and lo...

A novel fabrication strategy for alloyed Cd–Zn–S quantum dots–embedded glass with efficient red emission

“…According to the reported literatures, the radiative decay rate of two‐level system is determined by the optical density of states and the electromagnetic field strength at the local dielectric field of the emitter. The inhomogeneous local dielectric environment induced by different refractive indices (alloyed Cd–Zn–S composite: ∼2.45; glass: 1.46; air: 1.00) within subwavelength range of QDs would prolong the PL decay lifetime of QDs 55,56 . Moreover, gradient and shell structure of QDs also contribute to increasing the PL decay lifetime 57 .…”

“…The inhomogeneous local dielectric environment induced by different refractive indices (alloyed Cd-Zn-S composite: ∼2.45; glass: 1.46; air: 1.00) within subwavelength range of QDs would prolong the PL decay lifetime of QDs. 55,56 Moreover, gradient and shell structure of QDs also contribute to increasing the PL decay lifetime. 57 Therefore, the gradient structure of Cd x Zn 1−x S precursor solid solution and the complex local dielectric environment offered by glass matrix may be the reasons for the long lifetime.…”

High-Efficiency ZnS: Cu+, Al3+ Scintillator for X-ray Detection in a Non-Darkroom Environment

“…X-ray detecting has been widely utilized in industrial material inspection, lesion diagnosis, and scientific research. − Theoretically, X-ray detectors can be divided into direct and indirect types, in which the latter is cheaper and more stable. − However, common detection methods require sophisticated equipment and stringent environmental conditions, the scintillator signal will be treated further before it is fed back to the operator, especially the indirect detection, which collects the visible light signal from scintillator conversion in a non-darkroom. Due to the light adaptation phenomenon of human eyes, it is facile for people to observe luminescent objects in the dark .…”

Color‐Tunable and Stable Copper Iodide Cluster Scintillators for Efficient X‐Ray Imaging

“…[ 10 , 11 , 12 , 13 ] However, conventional scintillators often suffer from hygroscopicity due to the existence of strong ionic bonds. [ 14 ] In addition, luminescent ion‐based scintillation enables non‐tunable emission color because the luminescence of dopants, especially lanthanides, is inert to the host lattices in most cases due to the shielding effect of the 4f electrons by the completely filled 5s 2 and 5p 6 sub‐shells. [ 15 , 16 , 17 ] The emerged lead halide perovskite nanoscintillators with size‐/composite‐dependent bandgap characteristics add the feasibility to the production of multicolor radioluminescence (RL) covering the entire visible region, largely expanding the tools for multicolor radiation detection.…”