Highly Effective Hybrid Copper(I) Iodide Cluster Emitter with Negative Thermal Quenched Phosphorescence for X‐Ray Imaging

Abstract

The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)4Cu4I4, where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra‐bright triplet yellow‐orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon‐assisted de‐trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X‐ray imaging. The (DBA)4Cu4I4 wafer demonstrates a light yield higher than 104 photons MeV−1 and a high spatial resolution of ≈5.0 lp mm−1, showing great potential in practical X‐ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.

One‐Dimensional Chiral Copper Iodide Chain‐Like Structure Cu4I4(R/S‐3‐quinuclidinol)3 with Near‐Unity Photoluminescence Quantum Yield and Efficient Circularly Polarized Luminescence

“…[28,29,49,50] The Cu 4 I 4 cubane tetramers based hybrid compounds usually exhibit bright emission with high PLQYs, comparing with other Cu n I n nanoclusters. [28,29,[51][52][53] The strong Cu−Cu interactions as a result of short Cu−Cu interatomic distances in these Cu 4 I 4 cubane tetramers, generally lead to cluster-centered (CC) luminescence.…”

Thermally Activated Delayed Fluorescence Coinage Metal Cluster Scintillator

“…The light yield of 1 was calculated to be 26 000 photons MeV −1 by using the integral area ratio of the emission peak with a Bi 4 Ge 3 O 12 crystal as reference (Figure S4). 15 The light yields of CsI:Tl, YAlO 3 :Ce, and Bi 4 Ge 3 O 12 are 66 000, 21 000, and 10 000 photons MeV −1 , respectively. 24 These results suggest that the radioluminescence properties of 1 can match the commercial inorganic scintillators.…”

“…Moreover, due to the inherent heavy atomic core, metal clusters have a good X-ray absorption potential. Recently, Cu–I-cluster-based phosphorescence scintillators have drawn the attention of researchers, and Cu–I clusters with various radioluminescence properties have been reported successively. − However, the phosphorescence character of these clusters causes the singlet excitons not to be used for radioluminescence effectively, limiting their exciton utilization rate. To solve this problem, introducing the thermally activated delayed fluorescence (TADF) property into the metal cluster scintillators has become a promising approach.…”

Colloidal Cu4I4 Clusters for High-Resolution X-ray Imaging Scintillation Screens

“…Very recently, Sun and co-workers presented a novel copper iodide cluster scintillator, Cu 4 I 4 (DBA) 4 , with a light yield of ∼12842 photons MeV −1 . 41 However, the spatial resolution of the X-ray image taken with the Cu 4 I 4 (DBA) 4 wafer is only ∼5.0 lp mm −1 , which still falls far behind the standard for high-resolution imaging. Therefore, exploring new copper-based cluster scintillation screens and novel processing techniques to further improve their scintillation performance is a promising direction for X-ray imaging.…”

“…Copper halide clusters have been extensively investigated because of their large structural diversity and unique photophysical properties, such as high PLQY even in the solid state as well as thermo- and mechanochromism. , By virtue of these luminescence properties, copper halide clusters have found applications in various fields such as light-emitting diodes, bioimaging, and optical, temperature, and pressure sensors. − Because of the existence of heavy copper halide cores, copper clusters with high PLQY were also employed as scintillation materials. − For instance, Kirakci et al first discovered that Cu 4 I 4 (PPh 3 ) 4 and Cu 4 I 4 (py) 4 clusters with cubane-like structures have strong radioluminescence (RL) under X-ray excitation . Zhao et al expanded further on the scintillation properties of Cu 4 I 4 (py) 4 clusters and explored multicolor cluster scintillators .…”