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Проведены исследования структуры, ИК-спектров поглощения, морфологии и спектральных характеристик фотолюминесценции полученных методом гидротермального синтеза твердых растворов Lu1-x-yCexTbyBO3. Согласно данным рентгенофазового анализа, полученные в результате гидротермального синтеза при T=200oC образцы Lu1-x-yCexTbyBO3 имеют структуру ватерита, и все дифракционные пики соответствуют гексагональной фазе с пр.гр. P63/mmc, изоструктурной чистому LuBO3. Отжиг этих образцов при T= 970oC приводит к изменению структурной модификации и переходу образцов в моноклинную фазу с пространственной группой C2/c. Обнаружено, что после отжига этих образцов при T=800-970oC интенсивность свечения ионов Tb3+ при возбуждении в полосе поглощения ионов Cе3+ увеличивается более чем на два порядка и становится значительно выше, чем в соединениях такого же состава, полученных при высокотемпературном синтезе. В то же время отжиг бората лютеция, легированного только тербием, не приводит к заметному изменению интенсивности свечения ионов Tb3+. Обсуждаются возможные причины многократного усиления свечения ионов тербия при отжиге полученного методом гидротермального синтеза ортобората лютеция, легированного церием и тербием. DOI: 10.21883/FTT.2017.06.44487.426

The structure, IR absorption and luminescence spectra of solid solutions of Lu 0.99 -x Gd x Eu 0.01 BO 3 at 0 ≤ x ≤ 0.15 were studied. The correspondence between the structure and spectral characteristics of these compounds was established. It is shown that at x ≤ 0.05, the orthoborates Lu 0.99 -x Gd x Eu 0.01 BO 3 , consisting of lutetium borate LuBO 3 , which has two stable structural modifications (calcite and vaterite), and gadolinium borate GdBO 3 , which has only one structural modification (vaterite), form a solid solution with a calcite structure and a microcrystal size of 15-20 μm. As x increases, the amount of vaterite phase increases sequentially, and at x ≥ 0.1, the entire volume of the sample has a vaterite structure. At Gd 3+ concentration in the range of 0.05 < x ≤ 0.1, the samples of Lu 0.99 -x Gd x Eu 0.01 BO 3 are two-phase. It is shown for the first time that at x > 0.05, the vaterite phase appears both in the volume of large microcrystals (15-20 μm) and in the form of small microcrystals (1-2 μm).

The structure and the IR absorption and luminescence spectra of the Lu0.98-хInхEu0.02BO3 orthoborates are studied at 0 ≤ x ≤ 0.1. The Lu1-xInxBO3 solid solution, which consists of lutetium borate LuBO3 having two stable structural modifications (calcite, vaterite) and indium orthoborate InBO3 having one structural modification (calcite), crystallizes at x = 0.1 to form a calcite structure almost throughout the volume. We showed that the structural transformations in the Lu0.98-хInхEu0.02BO3 orthoborates induced by an increase in the In3+ ion concentration begin in the near-surface layers of the orthoborate microcrystals. The amount of calcite increases in the sample volume with x, and calcite occupies 98% of the Lu0.88In0.1Eu0.02BO3 sample volume.

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The main focus of this paper is the description of qualitatively new facilities for diagnostics of biological and medical objects and medical therapy obtained by applications of nanocrystalline scintillators. These facilities are based on abilities of nanoscintillators to selective conjugation with various biomolecular objects and noticeable variations of their atomic structures, X-ray diffraction (XRD) patterns, and light-emission characteristics induced by modifications of conditions on their external surfaces. Experimental results presented in this paper provide development of detection in vivo just inside a living organism of various viruses, cancer cells, and other pathological macromolecules by means of scanning X-ray diffractometry of nanoparticles introduced into the body. These data are produced by selective adsorption of pathological bioobjects by these nanoparticles and subsequent modifications of their XRD patterns. Application of narrow collimated X-ray beams and new types of X-ray detector matrices providing microscopic spatial resolution due to usage of nanoscintillators enables determination of the regions where these pathologies are localized with high accuracy. The procedure of detection of pathological organelles by this method improves possibilities for effective destruction of these pathologies by low-dose X-ray irradiation of the places of their localization. High effectiveness of this X-ray destruction is provided by concentrated absorption of X-ray quanta by the nanoscintillators and direct transfer of the absorbed energy to the pathological objects that are attached to the absorbing particles. Constructions of 3-D radiation detector matrices providing necessary microscopic spatial and angular resolutions of X-ray imaging are described on the basis of nanoscintillators, fiber light guides, and microcapillary matrices.

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