Near-Unity Energy Transfer from Uranyl to Europium in a Heterobimetallic Organic Framework with Record-Breaking Quantum Yield

Abstract

Lanthanide organic frameworks (Ln-MOFs) have attracted increasing research enthusiasm as photoluminescent materials. However, limited luminescence efficiency stemming from restricted energy transfer efficiency from the organic linker to the metal center hinders their applications. Herein, a uranyl sensitization approach was proposed to boost the luminescence efficiency of Ln-MOFs in a distinct heterobimetallic uranyl-europium organic framework. The record-breaking photoluminescence quantum yield (PLQY, 92.68%) among all reported Eu-MOFs was determined to benefit from nearly 100% energy transfer efficiency between UO2 2+ and Eu3+. Time-dependent density functional theory and ab initio wave-function theory calculations confirmed the overlap of excited state levels between UO2 2+ and Eu3+, which is responsible for the efficient energy transfer process. Coupled with intrinsically strong stopping power toward X-ray of the uranium center, SCU-UEu-2 features an ultralow detection limit of 1.243 μGyair/s, outperforming the commercial scintillator LYSO (13.257 μGyair/s) and satisfying the requirement of X-ray diagnosis (below 5.5 μGyair/s) in full.

Synthetic Control of Thorium Metal‐Organic Frameworks for Sequencing and Sensing of Radioiodine Species

“…[ 1‐4 ] However, obtaining a comprehensive understanding of their structures and physiochemical properties represents the crucial first step. [ 5‐9 ] Actinide‐bearing metal‐organic frameworks (An‐MOFs), which are constructed from actinide centers and organic linkers in a hierarchical manner, have attracted particular attention due to their extensive range of synthetically accessible and remarkable structures. [ 10‐15 ] An‐MOFs can inherit the combinatorial advantages of high porosity, stability, and modularity of MOFs, which in conjunction with the properties of actinides, renders repurposing radioactive waste and expanding the applications of actinide‐bearing materials feasible.…”

Highly Efficient Stable Luminescent Radical-Based X-ray Scintillator

“…X-ray scintillators have widespread applications in medical imaging, X-ray nondestructive inspection, electron microscopy, and high-energy particle detectors. − The development of X-ray scintillators with high X-ray excited luminescence (XEL) efficiency has attracted widespread attention. − For classic closed-shell X-ray scintillators whose electrons are in pairs, the radioluminescence originated from the radiative transition of excitons from the singlet/triplet state to the ground state (Figure A). However, suffering from spin-forbidden transition, the triplet exciton utilization rate is usually limited. , Thus, the major challenge for the development of high-performance X-ray scintillators was to find an effective strategy to increase the triplet exciton utilization rate. , In recent years, phosphorescent scintillators and thermally activated delayed fluorescence (TADF) scintillators have been reported in succession, which significantly increased the triplet exciton utilization rate and pointed a new direction for the development of high-performance X-ray scintillators. − Nevertheless, the molecular design and material synthesis of these new X-ray scintillators are still a challenge, and it is of great significance to find a universal strategy to design high-performance X-ray scintillators with a high exciton utilization rate.…”

Local Structure and Speciation-Driven UO22+ → Sm3+ Energy Transfer for Enhanced Luminescence in Li2B4O7

“…The quest for red-emitting phosphors to compensate for the red spectral region aroused huge scientific interest in exploring novel Eu 3+ and Sm 3+ -based phosphors. − Sm 3+ phosphors are promising for achieving orange red emissions on near ultraviolet (NUV) and blue excitations . Despite the large progress, the problem of insufficient molar absorption coefficients of Ln 3+ ions in the NUV region due to parity forbidden 4f → 4f transitions needs to be tackled. , The introduction of sensitizer ions in the host matrix is a promising approach to improve the Ln 3+ emission via energy transfer (ET) routes. ,, …”

“…15,16 The introduction of sensitizer ions in the host matrix is a promising approach to improve the Ln 3+ emission via energy transfer (ET) routes. 15,17,18 Uranyl ions (UO 2 2+ ) are well-known for a strong absorption in the NUV and blue spectral region, and various reports have explored the efficiency of ET in UO 2 2+ → Eu 3+ pair. The 5 D 0 energy levels of Eu 3+ emissive states (∼20,000 cm −1 ) which resulted in effective sensitization.…”

“…The 5 D 0 energy levels of Eu 3+ emissive states (∼20,000 cm −1 ) which resulted in effective sensitization. 15,17,19,20 Wang et al have investigated the 4f/5f energy transfer between actinide (uranyl (VI)) and lanthanide (III) centers in europium-incorporated uranyl coordination polymers. 21 A tunable 4f/5f bimodal emission was reported for the first time in heterobimetallic compounds.…”