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We report for the first time the optimized content and excellent scintillation properties of single crystalline film (SCF) scintillators of multicomponent Gd3–xLux Al5–yGay O12:Ce garnet compounds grown by liquid phase epitaxy (LPE) method. The Gd1.5Lu1.5Al2.75Ga2.25O12:Ce and Gd3Al2.75–2Ga2.25–3O12:Ce SCF show the light yield (LY) comparable with that of high‐quality bulk crystal analogues of these garnets but faster scintillation decay and very low thermoluminescence in the above room temperature range. To our knowledge, these SCF possess the highest LY values ever obtained in LPE grown garnet SCF scintillators exceeding by at least 1.5–1.6 times the values previously reported for SCF scintillators. Left figure: image of Gd1.5Lu1.5Al2.75Ga2.25O12:Ce (PbO) (inset, left) and Gd3Al2.35Ga2.65O12:Ce (BaO) (inset, right) SCF scintillators, grown by LPE method onto Gd3Al2.5Ga2.5O12 (GAGG) substrate; in the middle, green–yellow light emitting by Gd1.5Lu1.5Al2.75Ga2.25O12:Ce (BaO) SCF under 350 nm laser illumination. Right figure: XRD pattern of (1200) planes of the Gd1.5Lu1.5Al2.75Ga2.25O12:Ce (PbO) (black) and Gd3Al2.75Ga2.25O12:Ce (BaO) (red) SCFs, grown onto GAGG substrates. The film/substrate lattice misfit is –0.73% and –0.3%, respectively. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

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-The nature of the intrinsic luminescence of the lutetium aluminum garnet Lu 3 Al 5 O 12 (LuAG) has been analyzed on the basis of time-resolved spectral kinetic investigations upon excitation of two model objects, LuAG single crystals and single-crystal films, by pulsed X-ray and synchrotron radiations. Due to the differences in the mechanisms and methods of crystallization, these objects are characterized by significantly different concentrations of Lu Al antisite defects. The energy structure of luminescence centers in LuAG single crystals (self-trapped excitons (STEs), excitons localized near antisite defects, and Lu Al antisite defects) has been established. For single-crystal LuAG films, grown by liquid-phase epitaxy from a Pb-containing flux, the energy parameters of the following luminescence centers have been determined: STEs in regular (unperturbed by the presence of antisite defects) sites of the garnet lattice and excitons localized near Pb 2+ ions. The structure of the luminescence centers, related to the background emission of impurity Pb 2+ ions, has also been established in the UV and visible ranges. It is suggested that, in contrast to the two-halide hole self-trapping, a self-trapped state similar to STEs in simple oxides ( Al 2 O 3 , Y 2 O 3 ) is formed in LuAG; this state is formed by self-trapped holes in the form of singly charged O -ions and electrons localized at excited levels of Lu 3+ cations. PACS numbers: 78.55.-m

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Intrinsic emission of complex oxides with perovskite structure was analyzed in the undoped single crystal (SC) and single crystalline films (SCF) of YAlO 3 (YAP) using the time-resolved luminescence spectroscopy under excitation by synchrotron radiation. In contrast to bulk SC the YAP SCF are characterized by much lower concentration of YAl antisite and vacancy-type defects, which contribute to the intrinsic emission of YAP SC. Such a difference comes mainly from much lower temperature of the film growth using the Liquid Phase Epitaxy. For this reason, comparison of YAP SC and SCF appears very useful to study the nature of the intrinsic emission of perovskites consisting mainly of the exciton and defectrelated luminescence.1 Introduction The nature of intrinsic emission of oxides with the perovskite ABO 3 structures is still not clearly understood. The perovskites are complex oxides with two cation sublattices. The A cations are distributed over the octahedral position formed by six oxygen ligands whereas B cations are located in the voids between the octahedrons created by the twelve nearest oxygen ions. The intrinsic UV luminescence of these compounds was mainly investigated for the case of YAlO 3 perovskites (YAP) and usually consists of two or more bands in the UV region [1][2][3][4]. The positions and intensities of these bands depend on the method of material preparation, type and concentration of host defects [3,4].To clarify the nature of the intrinsic luminescence bands in YAP, various models have been proposed [1][2][3][4]. In earlier papers [1,2], the UV YAP emission in the bands at 5.9 and 4.0 eV was related to the decay of self-trapped excitons (STE) with the hole component, which is localized on the single-and twocharged oxygen ions in the form of О -and О 2 3-centers, respectively. At the same time due to high temperature crystallisation from melt usually in the oxygen-free atmosphere and existence of two cation sublattice the YAP single crystals (SC) always possess a certain concentration of the Y Al antisite defects (AD), as well as the vacancy-type defects (VD), first of all, the oxygen vacancies [5]. It was shown [6,7] that Y Al AD as analogues of the cation isoelectronic impurities in complex oxides, for instance, in garnets, create the emission and trapping centers, which contribute to the intrinsic luminescence of these compounds. Oxygen vacancies usually create the sites for one-or two-electron capture in the form of F + (V O¯) and F(V O ) centers which also contribute to the intrinsic emission of YAP SC [4,8]. Therefore, it is demanding to study the intrinsic luminescence of perovskites with different concentrations of such defects. The SC grown from melt with high concentration of AD and VD, and single crystalline films (SCF) of the same composition grown from melt-solution (MS) using Liquid Phase Epitaxy (LPE) offer

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