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We report the photon (PL), electron (CL) and X-ray (XEL) induced luminescence characteristics of high aspect ratio ultra-long (~ 50 µm) ZnO nanorods (NRs) and discuss the potential for fast X-ray detection based on the consistent and efficient visible emission (~ 580 nm) from ZnO NRs. Nanostructured ZnO scintillators were rearranged to form a vertically well-aligned NR design in order to help light absorption and coupling resulting in luminescent and fast scintillation properties. The design of the nanorod array combines the key advantages of a low-cost growth technique together with environmentally friendly and widely available materials. A low temperature hydrothermal method was adopted to grow ZnO NRs in one cycle growth and their structural, optical and X-ray scintillation properties were investigated. The relatively short (~ 10 µm) ZnO NRs emitting in the near-band-edge region were found to be almost insensitive to X-rays. On the other hand, the higher XEL response of long ZnO NRs, which is a key parameter for evaluation of materials to be used as scintillators for high quality X-ray detection and imaging, along with a decay time response in the order of ns confirmed promising scintillation properties for fast and high-resolution X-ray detector applications. [ABSTRACT FROM AUTHOR]

Conjugated BaI2:Eu (5 at.%) nanocrystalline particles were synthesized, decorated with golden nanoparticles (GNP). GNP demonstrated some hydrophilic effect, leading to the BaI2·H2O phase creation. The Eu2+ luminescence intensity was reduced according to the GNP content. This was due to the decreased number of Eu2+ ions in the BaI2, most probably, arising from the Au substitution for Ba competing with Eu. Moreover, the decay time of luminescence was decreased upon GNP content. This was explained by the moderation of negative charge in the GNP, leading to the repulsion with an electron in the excited Eu2+. [ABSTRACT FROM AUTHOR]

The glass‐ceramics (GC) of gadolinium aluminum gallium garnets with the expected composition of Gd3Al3Ga2O12:Ce and Gd3Al3Ga2O12:Ce,Be (GAGG:Ce and GAGG:Ce,Be, respectively) are fabricated by crystallization from the Gd2O3–Al2O3–Ga2O3–CeO2–SiO2–BeO (Gd:Ga:Al ratio is close to 3:2:3) glasses. The influence of Be2+ co‐doping (including doping level) on the luminescent properties of the GAGG is demonstrated. In particular, Be co‐doping results in the suppression of the Ce3+‐related radioluminescence (RL) and as a consequence, the light yield is lowered as well. The conclusion is made that Be2+ creates effective electron or hole trapping centers. [ABSTRACT FROM AUTHOR]

Glass ceramics based on Ce-doped garnets were fabricated by the controlled crystallization of CaO(MgO)–Y2O3–Al2O3–GeO2–SiO2–CeO2 glasses. The optimal conditions for transforming these glasses into ceramics by heat treatment were found by using differential scanning calorimetry: 1400 °C for MgO–Y2O3–Al2O3–GeO2–SiO2–CeO2 and 1500 °C for CaO–Y2O3–Al2O3–GeO2–SiO2–CeO2. The structure was characterized by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy techniques, while the emission properties were studied by photoluminescence (PL) spectroscopy. The fine structure of XRD patterns evidences contributions from garnets of different compositions. Spatially-resolved PL spectroscopy using confocal microscopy shows that the garnet crystallites have a layered structure. The capability of tuning the PL peak position within the range from 530 to 580 nm by changing the excitation wavelength was demonstrated. This effect is caused by the localization of Ce3+ ions at the positions with different crystal fields, which varies due to a composition gradient in the crystallites. These glass ceramics have high potential for exploitation as phosphors in high-power white light sources. [ABSTRACT FROM AUTHOR]

The search for engineering approaches to improve the scintillation properties of Gd3Al2Ga3O12 crystals and enable their production technology is of current interest. This crystal, while doped with Ce, is considered a good multi‐purpose scintillation material for detecting gamma‐quanta and neutrons. It is observed that co‐doping with Mg affected intrinsic defects in the crystal structure that create shallow electronic traps. Other point structure defects, which are based on local variations of the crystal stoichiometry, are significantly diminished by use of a co‐precipitated raw material. Nano‐structuring of the raw material enables production of a homogeneous precursor mixture for growing a crystal with minimal evaporation of Ga from the melt. The demonstrated nano‐engineering approach increased the light yield from the crystal by approximately 20%, enabling its applications in well logging. A technological approach to control defect formation in Gd3Al2Ga3O12:Ce crystalline material and minimize their effect on the crystal scintillation properties is successfully implemented. Co‐doping of the crystal with an aliovalent impurity acts as an efficient tool for reducing the crystal structure disordering, while use of co‐precipitated nanostructured raw material diminishes the effect of gallium evaporation from the melt during the crystal growth. [ABSTRACT FROM AUTHOR]