In Situ Fabrication of Cs₃Cu₂I₅: Tl Nanocrystal Films for High-Resolution and Ultrastable X-ray Imaging

Abstract

Cs 3 Cu 2 I 5 nanocrystals (NCs) are considered to be promising materials due to their high photoluminescence efficiency and X-ray hardness. However, the present strategy depends on tedious fabrication with excessive chemical waste. The evasive iodide ion dissociation, inadaptable ligand system, low stability, and relatively low light yield severely impede their applications. Herein, we develop an in situ fabrication strategy for a flexible and large-area Tl-doped Cs 3 Cu 2 I 5 NC-polymer composite scintillation film with a high light yield (∼48800 photons/ MeV) and improved stability. Tween 80 and phosphinic acid successfully inhibit the oxidation of iodide ions, and the films can be stored for at least six months. As a result, a high spatial resolution of 16.3 lp mm −1 and a low detection limit of 305 nGy air s −1 were achieved. A radioluminescence intensity of >80% was maintained after a total irradiation dose of 604.8 Gy. These results indicate the promising application of these copper halide NCs in low-cost, flexible, and high-performance medical imaging.

High-Performance Copper-Doped Perovskite-Related Silver Halide X-ray Imaging Scintillator

“…Recently, a series of low-dimensional metal halides have exhibited potential as feasible and promising scintillation materials by virtue of their high atomic weight, near-unity photoluminescence quantum yield (PLQY), and negligible reabsorption owing to the presence of self-trapped excitons (STEs). − For instance, Tang and co-workers reported a copper-based scintillator containing rubidium that exhibited a record high light yield (∼91 000 photons/MeV) . However, the high natural radioactivity of rubidium could greatly limit its potential for practical application.…”

High-Resolution X-ray Imaging Based on Solution-Phase-Synthesized Cs3Cu2I5 Scintillator Nanowire Array

“…These results demonstrate that the length of Cs 3 Cu 2 I 5 NWs is not proportional to concentration in the range of 0.80–1.20 mol·L –1 . There may be two possible reasons for this phenomenon. , First, a higher concentration leads to higher viscosity. In this case, the solution is probably restricted to the surface of AAO, closing to the supersaturation, resulting in preferential nucleation and growth at these sites relative to pores.…”

“…However, the imaging resolution is still rather limited due to the lack of a scintillation waveguide, especially for the solution-processed nanocrystal scintillators. 1,9,10,12,13 The spatial resolution is one of the key indicators to evaluate scintillation performance, which largely depends on the geometry and morphology of the scintillation screen (i.e., thickness, dimension, and shape). 14−16 Various methods have been utilized to improve the spatial resolution of scintillators (Table S1).…”

“…Recently, the lead-free Cu­(I)-based metal halides, represented by Cs 3 Cu 2 I 5 , are favored as scintillators due to their solution-processability, high photoluminescence quantum yield (PLQY), large Stokes shift, and negligible self-absorption. − Many studies focus on the synthesis of Cs 3 Cu 2 I 5 scintillators, including nanocrystals (NCs), ,, single crystals (SCs), , and polycrystalline powder, and their applications in X-ray detection and imaging. However, the imaging resolution is still rather limited due to the lack of a scintillation waveguide, especially for the solution-processed nanocrystal scintillators. ,,,, The spatial resolution is one of the key indicators to evaluate scintillation performance, which largely depends on the geometry and morphology of the scintillation screen (i.e., thickness, dimension, and shape). − …”

Mn4+-Doped Fluoride Nanocrystals Enable High-Resolution Red-Emitting X-ray Imaging Screens

“…Recently, lead halide perovskite nanocrystals (NCs) with a lower synthesis temperature than that used for traditional scintillators, high X-ray absorption efficiency, intense radioluminescence, a low X-ray detection limit, and the ability to be processed from solution have been extensively studied as a new generation of X-ray scintillators. − In addition, reduced light scattering from the small particles in nanoscintillators ensures high spatial resolution . Despite their promising X-ray detection performance, the potential commercial applications of lead halide perovskite NCs are limited by the toxicity of lead, their low stability, and their strong reabsorption due to their small Stokes shift. − In this context, new lead-free metal halide materials with high X-ray performance have received increasing interest. ,− Thereby, a lead-free composition, high stability, narrow-band emission, high PLQY, large Stokes shift, and low reabsorption of Mn 4+ -doped hexafluoride NCs motivated us to test them for X-ray detection applications.…”