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Abstract In this paper, BaAl 11 O 16 N (BAON) based oxynitride phosphors have been synthesized via the employment of the flux method and Eu2+/Mn2+ co-doped technique. The effects of different fluxes on phase formation of the phosphor have been investigated. It has been found that BaF 2 is the best flux to prepare BAON as it can decrease the pure phase-forming temperature (∼1550 °C) than the normal solid state synthesis (∼1700 °C). It also gives the best luminescence quantum efficiency. The crystallinity, morphology and grain size of the phosphor can be improved when more BaF 2 flux has been added. The photoluminescence (PL) spectra and decay curves for Eu2+/Mn2+co-doped BAON phosphors reveal that an efficient energy transfer (ET) from Eu2+ to Mn2+ takes place in the BAON host. The corresponding ET efficiencies and mechanisms are evaluated and the critical distance (R c) is calculated in terms of the experimental data and analysis. The emission colors of the co-doped phosphors can be tuned from blue to green by simply varying the doping concentrations of Mn2+. White light-emitting diodes (WLEDs) are fabricated by coating the as-prepared samples on a near ultraviolet (n- UV) LED chip to explore the real application potentials. The excellent performance of this WLEDs verifies that the co-doped phosphor can be used as an efficient green component. Graphical abstract Image 1 Highlights • A simple flux fusion routine for synthesizing BaAl 11 O 16 N:Eu2+,Mn2+ oxynitride phosphors. • Energy transfer between Eu2+ and Mn2+ takes a place in the BaAl 11 O 16 N host. • The WLEDs based on the as-prepared phosphors presents excellent warm white light performance. [ABSTRACT FROM AUTHOR]

The short-wavelength sub-nanosecond luminescence in BaF 2 material, discovered in the early 80s, gave a new direction to research into fast scintillators and phosphors. In contrast to 'typical' luminescence occurring within the forbidden band gap, the new type of emission was due to transitions between the upper core and valence bands. Thus it was named core-valence luminescence (CVL); the terms cross-luminescence and Auger-free luminescence have also been used. Given its unusual nature, this new luminescence process has attracted considerable interest in the field of condensed matter physics. During the sequent decades (till the end of the previous century) CVL has been experimentally observed in several dozen compounds and the conditions for detecting CVL have been established. Interest in this kind of luminescence increased in recent years due to the emergence of new methods of crystal synthesis, the development of high-speed solid-state photodetectors, and the construction of unique modern set-ups using synchrotron radiation. This paper analyzes the numerous studies of CVL, obtained mainly over the past decade. Experimental and theoretical data on this topic are considered in detail. Special attention is given to new results on scintillation characteristics of BaF 2 in the form of single crystals, ceramics, nanoparticles, and composites. The features of CVL in binary and ternary compounds are discussed. Some Cs- and Ba-based ternary halides show relatively high light yields and represent promising fast scintillators. The prospects of using materials with CVL as fast scintillators for time-of-flight positron emission tomography and other applications are deliberated. • Overview of recent theoretical and experimental findings on Core Valence luminescence. • Most attractive CVL crystals for ultrafast scintillator applications analyzed. • Prospects for future studies and underexplored CVL materials listed. [ABSTRACT FROM AUTHOR]

Our recent study was focused on the emission from Laser Induced Plasma (LIP) at the delay times of tenths of microseconds after the laser pulse. At these long delays, the spectrum is dominated by the broadband molecular emission and plasma induced luminescence (PIL) produced by a luminescent matrix; only solitary atomic emission lines can be seen. Barium fluoride BaF 2 activated by thulium (Tm) is a famous scintillator that presents the promising object for LIP in terms of both the potential for BaF molecular emission and Tm3+ PIL. The detection of molecular and PIL bands presents a new opportunity for analysis of halogens and rare-earth elements, which are the difficult objects for LIBS. In this paper, we show that the UV, Green, Extreme Red, and Infrared molecular bands from BaF and blue luminescence from Tm3+ are present in the LIP emission spectra while the detection of atomic emission from F I and Tm I was impossible with the same experimental setup. Thus, the detection of molecular emission and PIL can be more sensitive than the traditional detection of emission from atoms and ions. Unlabelled Image • We studied LIBS of BaF 2 activated by Tm3+. • Emission and temporal behavior of BaF molecules were determined. • Plasma Induced Luminescence of Tm3+ was found. [ABSTRACT FROM AUTHOR]