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Scintillators with high light yield, spatial resolution, and detection sensitivity are desirable for X‐ray imaging. Howerer, it remains challenging to improve the light yield and radiation detection capability of alkali metal rare‐earth fluoride (ALnF4). Herein, a type of Cu2+ ion heterovalent co‐doped LiLuF4:Tb,Cu microcrystalline scintillation material with high light yield, persistent, and thermostimulated luminescence is obtained by defect engineering. The heterovalent codoping strategy not only increases the radioluminescence (RL) intensity, but also introduces more carrier traps in the material to enhance the long‐afterglow and thermoluminescence intensity of LiLuF4:Tb microcrystals. After doping of 3 mol% Cu2+ ions, the RL efficiency is increased by 88.61%, and the X‐ray detection limit of LiLuF4:Tb,Cu reaches 2.7928 nGy·s‒1. This detectivity is considerably lower than the medical imaging requirements (5.5 µGy·s‒1). Furthermore, a large‐area flexible scintillation film of dimensions 30 × 30 cm2 is prepared to achieve high spatial resolution X‐ray imaging of 22 LP mm−1@MTF(modulation transfer function) = 0.2. Besides, this flexible film enables X‐ray imaging of curved objects and stores optical information for >48 h. This work provides a paradigm for improving the RL intensity and X‐ray detection sensitivity of alkali rare‐earth fluorides by crystal defect engineering, and enriches X‐ray high resolution extended imaging applications. [ABSTRACT FROM AUTHOR]

X-ray detectors based on scintillators are widely used in the fields of medical imaging, high-energy physics, geological exploration, and industrial detection. The development of scintillation materials with different characteristics has become the focus of considerable research interest. Herein, we report a facile hydrothermal synthesis of Gd- and Eu-codoped LiLuF4 microcrystals (MCs), which exhibit strong luminescence of Eu3+ ion characteristic emission, characterized by distinct red fluorescence emission. The research shows that Gd3+ co-doping effectively improved the sensitivity and light yield of LiLuF4:Eu MCs by regulating the proportion of co-doping ions. In addition, the detection limit is 140.72 nGy s−1 for LiLuF4:Eu,Gd MCs, approximately 39 times lower than the dose requirement of medical diagnosis. Based on LiLuF4:Eu,Gd MCs with the superior scintillation properties, a MC-composited film with 250 μm thickness was prepared by a direct coating method. The uniform and high-loading scintillation film exhibits outstanding imaging performance with a high spatial resolution of 14.8 LP mm−1, which confirms the application potential of X-ray imaging. [ABSTRACT FROM AUTHOR]

Enhancing the thermoelectric transport properties of conductive polymer materials has been a long-term challenge, in spite of the success seen with molecular doping strategies. However, the strong coupling between the thermopower and the electrical conductivity limits thermoelectric performance. Here, we use polaron interfacial occupied entropy engineering to break through this intercoupling for a PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonate)) thin film by using photochromic diarylethene (DAE) dopants coupled with UV-light modulation. With a 10-fold enhancement of the thermopower from 13.5 μV K−1 to 135.4 μV K−1 and almost unchanged electrical conductivity, the DAE-doped PEDOT:PSS thin film achieved an extremely high power factor of 521.28 μW m−1 K−2 from an original value of 6.78 μW m−1 K−2. The thermopower was positively correlated with the UV-light intensity but decreased with increasing temperature, indicating resonant coupling between the planar closed DAE molecule and PEDOT. Both the experiments and theoretical calculations consistently confirmed the formation of an interface state due to this resonant coupling. Interfacial entropy engineering of polarons could play a critical role in enhancing the thermoelectric performance of the organic film. [ABSTRACT FROM AUTHOR]

Scintillators, which can emit visible photons under γ- or X-ray excitation, are widely used in radiation detection. Traditional inorganic scintillators usually have some drawbacks, such as hygroscopicity or a high synthesis temperature, and most of them are poisonous. Hence, we report the synthesis of metal iodate scintillators (Eu(IO3)3 and Tb(IO3)3) by a facile hydrothermal reaction that exhibit good radioluminescence (RL) intensity. To further increase the RL intensities, we prepared Eu(IO3)3:xSm and Tb(IO3)3:xGd with stronger RL intensities and higher sensitivities than BaF2 and PbWO4 powders when x = 3%. Furthermore, we obtained scintillating films consisting of Eu(IO3)3:3%Sm and Tb(IO3)3:3%Gd for X-ray imaging. Our Eu(IO3)3:3%Sm and Tb(IO3)3:3%Gd films revealed excellent luminescence under high-energy X-ray excitation and spatial resolutions down to 9 lp mm−1 and 8 lp mm−1, respectively. Thus, these films can be regarded as candidate materials for X-ray imaging. [ABSTRACT FROM AUTHOR]

The current development direction of magneto-optical (MO) isolators involving miniaturisation and application in high-power lasers encounters difficulties in material application because preparing materials with excellent optical quality and a high Verdet constant remains a challenge. Herein, (Tb1−xCex)3Sc2Al3O12 (x = 0.001, 0.0025, 0.005, 0.01, 0.015, 0.02) MO ceramics with different doping concentrations were prepared by vacuum sintering. The phase structure, element distribution, microstructure, relative density, optical properties, surface properties and MO properties of the (Tb1−xCex)3Sc2Al3O12 ceramics were also characterised. Experimental characterisation reveals that the (Tb1−xCex)3Sc2Al3O12 ceramics have a pure Tb3Sc2Al3O12 (TSAG) phase and exhibit an excellent uniform element distribution. In addition, no secondary phase was detected in FESEM images with the increase in Ce concentration. However, a few small-sized residual pores, which remain entrapped in the Ce0.015TSAG and Ce0.02TSAG ceramics, can be observed. Moreover, all the obtained ceramics have good optical quality, and the in-line transmittances of the (Tb1−xCex)3Sc2Al3O12 ceramics at 1064 nm are 81.7%, 83.7%, 80.0%, 84.0%, 68.8% and 77.7%. The Verdet constant of the ceramics is optimised by Ce doping, and the Verdet constants of all the ceramics at the test wavelength are better than those of TSAG ceramic. The Verdet constant of the Ce0.01TSAG ceramic is still superior to that of the TSAG ceramic in the same temperature range. Finally, the extinction ratio values for the CexTSAG (x = 0.001, 0.0025, 0.005, 0.01) ceramics exceeded 40 dB. The Ce0.01TSAG ceramic shows the best optical transmittance, the highest magneto-optical FoM values and the highest Verdet constants. Thus, this ceramic can be used for a high-power laser in the visible and near-infrared regions in the future. [ABSTRACT FROM AUTHOR]