Undoped and Tl‐Doped Cs₃Cu₂I₅ Thin Films as Potential X‐ray Scintillators

Abstract

0D halide perovskite Cs3Cu2I5‐based nanocrystals and bulk crystals are proven to be sensitive and efficient scintillators for X‐ray and γ‐ray detection. Herein, undoped and Tl‐doped Cs3Cu2I5 microcrystalline films are synthesized by a thermal evaporation method. Both films crystallize into a Pnma space group of orthorhombic crystal lattice with preferred (004) growth orientation. The undoped Cs3Cu2I5 thin film shows a sole emission peaking at 440 nm associated with the self‐trapped exciton emission. Doping of Tl+ ions introduces another emission that peaks at 520 nm. The scintillation efficiency of both undoped and Tl‐doped Cs3Cu2I5 thin films is about one‐third of that of CsI:Tl thin film with the same size and thickness. Within the first 5 s after X‐ray cutoff, afterglow signals of both the undoped and Tl‐doped Cs3Cu2I5 thin films are over one order of magnitude lower than that of CsI:Tl thin film.

Light Emission of Self‐Trapped Excitons in Inorganic Metal Halides for Optoelectronic Applications

“…For example, the intrinsic and Tl + ‐doped Cs 3 Cu 2 I 5 single crystal was demonstrated by several groups to be the bright and efficient γ‐ray scintillator, which revealed the potential of STE‐emission metal halides as the promising alternatives for the high‐performance γ‐ray detection. [ 100–103 ]…”

“…For example, the intrinsic and Tl + -doped Cs 3 Cu 2 I 5 single crystal was demonstrated by several groups to be the bright and efficient γ-ray scintillator, which revealed the potential of STE-emission metal halides as the promising alternatives for the high-performance γ-ray detection. [100][101][102][103] Another critical design principle for scintillators is to lower the afterglow which is known to produce ghost images through a "memory effect" and deteriorates the quality of demanded images. As a measure of the contribution of phosphorescence in scintillation, the afterglow is the amplitude of the luminescence signal excited by ionizing radiation and measured after a fixed time, for example, 10τ r (τ r = radiating time of the luminescence transition).…”

Potassium-regulated lead-free cesium copper iodide Cs3Cu2I5 perovskites with enhanced scintillation properties and their application in high-resolution X-ray imaging

“…28,36 Although several measures have been adopted for improving the PLQYs of Cs 3 Cu 2 l 5 powders, single crystals, and thin films, their light yield is still far below the theoretical limit, which seriously hinders their application in cost-effective and high-resolution flexible X-ray detection. 33,39,40 Furthermore, less research has focused on the effect of K + doping on the scintillation properties of Cs 3 Cu 2 l 5 to date. Therefore, it is necessary to obtain a Cs 3 Cu 2 l 5 flexible material with high scintillation performance by a doping strategy to modify the optical and optoelectronic properties of halide perovskites.…”

Mn2+‐Activated Cs3Cu2I5 Nano‐Scintillators for Ultra‐High Resolution Flexible X‐Ray Imaging

“…Flexible X-ray detectors have great advantages in threedimensional imaging of non-flat or irregularly shaped objects, and are considered to be an effective solution to reduce misdiagnosis caused by vignetting problems, exhibiting great superiority in medical radiography, nondestructive inspection, is still plenty of room for further improvement in the scintillator efficiency and environmental stability before such an application can be realized outside of the laboratory. [31][32][33] As an effective approach to improve the performance of nanomaterials, doping with transition metal ions has been widely explored to modulate the optical, electrical and magnetic performances via introducing strong exchange interactions of the d orbit electrons with charge carriers of the host semiconductors and activating forbidden transition in the host materials. [34][35][36][37][38][39] Taking the most representative Mn 2+ ion as an example, the replacement of Pb 2+ with Mn 2+ in CsPbX 3 perovskite can generate intense sensitized dopant luminescence to boost photoluminescence (PL) efficiency by introducing new carriers transition pathway, and stabilize specific crystallographic phases by increasing crystal formation energy.…”