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Bismuth cations (e.g., Bi3+, Bi2+) are very promising non‐rare‐earth activators in persistent luminescence (PersL) materials. Recently, much work has been devoted to modulating the host structures and defects to obtain high‐intensity luminescence and/or tunable excitation and emission bands of Bi‐activated persistent phosphors. A timely review on Bi‐based PersL phosphors would be highly attractive for future materials' design and applications. The present review discusses the recent advances in Bi‐activated PersL phosphors with focus on the structure–defect–property relationships. Firstly, the basic ionic configurations of Bi cations as an activator are discussed in detail, followed by the classification as well as elaboration of Bi‐activated PersL phosphors according to emission wavelength. Then, the modulation strategies of PersL through adjusting the local structures are highlighted, which include defect engineering and theoretical prediction. These strategies allow for the effective regulation of PersL in Bi‐activated phosphors that have extensively been explored in information storage, X‐ray imaging, stress sensing, anti‐counterfeiting, etc. Finally, future challenges and perspectives toward Bi‐activated PersL phosphors are proposed. This review provides solid guidelines of designing diverse PersL materials with tunable properties for various optical applications in the future. [ABSTRACT FROM AUTHOR]

Eu3+-doped GdAlO3 (Eu:GAP) and Gd0.5La0.5AlO3 (Eu:GLAP) perovskite single crystals were successfully grown using the optical floating zone (OFZ) method. The microstructure, optical, photoluminescence (PL) and radioluminescence (under X-ray excitation, XEL) were investigated. Under the PL excitation of 275 nm, obvious emission bands peaking at 556 nm, 592 nm, 617 nm, 625 nm, 655 nm, and 706 nm were demonstrated, which correspond to the 5D0 → 7Fj (j = 0–4) transitions of Eu3+. The grown Eu:GAP single crystal showed a stronger PL intensity compared with that of Eu:GLAP in the red light region. After annealing at 1000 °C for 4 h in weak reductive atmosphere (Ar + 5% H2), a slight redshift and dramatic enhancement of PL and XEL intensity occurred. In addition, Eu:GLAP show a more intense XEL emission than that of Eu:GAP. Considering their different densities, these two kinds of red luminescence phosphors are proposed to be promising in a wide field of X-ray imaging, warm white, or plant lighting, respectively. [ABSTRACT FROM AUTHOR]

Ce3+, Pr3+ co-doped Lu3Al5O12 (Ce, Pr:LuAG) single crystals and ceramics were prepared using the optical floating zone (OFZ) and reactive vacuum sintering methods, respectively. The microstructure, photo- (λex = 450 nm), and radio-luminescence (under X-ray excitation) performance, as well as scintillation light yield (LY, under γ-ray, 137Cs source) of both materials, were investigated and compared. Ce, Pr:LuAG ceramics had an in-line transmittance of approximately 20% in the visible light range, while the analogous crystals were more transparent (~65%). The X-ray excited luminescent (XEL) spectra showed the characteristic Ce 3+ and Pr3+ emissions located at 310 nm, 380 nm, and 510 nm. The highest LY of the Ce, Pr:LuAG ceramics reached 34,112 pho/MeV at 2 μs time gate, which is higher than that of a single crystal. The ratio of LY values (LY2/LY0.75) between shaping times of 0.75 μs and 2 μs indicated a faster scintillation decay of ceramics regarding single crystals. It was ascribed to the lower effective concentration of luminescent activators in single crystals because of the coefficient segregation effect. [ABSTRACT FROM AUTHOR]

Environmental problem caused by carbon emission is of widespread concern. Involving CO2 as C1 resource into chemical synthesis is one of the most attractive ways for carbon recycling. Herein, the first example of host–guest composites featuring metal–organic framework (MOF)‐encapsulated binuclear N‐heterocyclic carbene (NHC) complex, Co2@MIL101, was developed with the molecularly dispersed [Co(IPr)Br]2(μ‐Br)2 (Co2) loading in the cage of MIL‐101(Cr) via a "ligand‐in‐dimer‐trap" strategy, which was comprehensively investigated through various techniques including synchrotron X‐ray absorption, electron microscopy, X‐ray diffraction, solid‐state nuclear magnetic resonance spectroscopy, and others. The noble‐metal‐free double‐sites catalyst Co2@MIL101 exhibited promising stability, activity, efficiency, reusability, and substrate adaptability for converting CO2 into various formamides with amines and hydrosilanes and achieved the best performance for one of the most useful formamides, N‐methyl‐N‐phenylformamide (MFA), among the recyclable catalysts at ambient conditions, providing a reliable approach to successfully unify the advantages of both homo‐ and heterogeneous catalysts. Density functional theory calculations were applied to illustrate the superior activity of the binuclear NHC complex center as double‐sites catalyst toward the activation of CO2. [ABSTRACT FROM AUTHOR]

SrAl2O4:Eu2+, Dy3+ has been widely studied as a classical persistent phosphor due to its stability and long green-afterglow duration. In this study, a series of Ce3+ co-doped SrAl2O4:Eu2+, Dy3+ phosphors were prepared by the traditional solid state reaction method, sintering under Ar + 5% H2 atmosphere in the temperature range of 1300–1500°C. The effect of Ce3+ co-doping on luminescence performance of SrAl2O4:Eu2+, Dy3+ was investigated at Ce3+ concentration of 0–0.3 at %. Under excitation wavelengths of 365, 400 and 460 nm, respectively, the luminescence intensity was found to increase linearly with rise of sintering temperature or Ce3+ doping concentrations. It was ascribed to the sufficient crystallization at high sintering temperature as well as the high absorption cross section of Ce3+ ion. Besides, the Ce3+ co-doping speeds up the afterglow time without introducing the emission wavelength shift. Therefore, Ce3+ co-doped SrAl2O4: Eu, Dy is a promising high efficient phosphor for compensated the dark period in alternating current driven light-emitting diodes (AC-LED) lighting. [ABSTRACT FROM AUTHOR]