Deep submicrometer YAG:Ce phosphor particles with high photoluminescent quantum yield prepared by flame spray synthesis

Abstract

YAG:Ce materials have been extensively studied as phosphors for blue to white light conversion. In the last years, the preparation methods of YAG:Ce powders in the nanometric scale have received intensive attention due to their special optical properties. In this context, the preparation of luminescent particles with high quantum yield (QY) and particle size in the deep submicrometer range is the main focus of this work. Amorphous and hexagonal YAG:Ce nanoparticles (<20 nm) with the stoichiometric composition of YAG:Ce were synthesized by liquid-feed flame spray synthesis. The crystal phase, particle size, and specific surface area (SSA) evolution with the calcination temperature were investigated. A direct conversion from the amorphous/hexagonal phase to the cubic one was observed at T≥900°C, together with an increase in the particle size into the range 100-350 nm and a corresponding decrease in the SSA. Zeta potential of the particles in aqueous dispersions and their photoluminescent properties were characterized. The QY increased for the phosphor powders with lower Ce 3+ concentration. The highest QY of 70%-72% was obtained for powders containing cerium doping of 0.1 mol % and spanning the size range between 130 and 270 nm. K E Y W O R D SCe, flame spray synthesis, photoluminescence, quantum yield, YAG

Towards a Correlation between Structural, Magnetic, and Luminescence Properties of CeF3:Tb3+ Nanocrystals

“…Figure 8 shows the Commission Internationale de l’Eclairage (CIE) chromaticity diagram of CeF 3 :Tb 3+ nanocrystalline powder with the coordinates x = 0.252 and y = 0.725 in the region of green light characteristic to the Tb 3+ luminescence region. In the present case, the quantum yield (QY) of the Tb 3+ ions green-related luminescence is about 20% (for 250 nm excitation wavelength) and is smaller than for YAG:Ce phosphor nanoparticles (of about 130 to 270 nm size), where a QY of 70–72% was reported [ 32 ]. On the other hand, the QY is influenced by the nanocrystals’ size: the QY of Ca 3 Sc 2 Si 3 O 12 :Ce 3+ nanopowders is about 50% and increases to 70–72% for microparticles [ 33 ].…”

Ce3+ and Eu3+ emissions in YAG via a core-shell strategy for warm white LED lighting

“…Based on the results presented in this work, the core-shell methodology presents some advantages in comparison with the materials prepared by co-doping such as (a) no competition between Ce and Eu for substituting the Y position in the YAG matrix; and (b) the core and the shell can be optimized independently, achieving the highest PL emission in both cases and avoiding the Ln quenching at high concentrations [3,5].…”

“…YAG:Ce is a yellow phosphor with a high quantum efficiency and good thermal and chemical stability [2][3][4]. The strategies to achieve warmer white light have been codoping YAG:Ce with Pr, Cr, Gd and Eu among others [5][6][7][8][9] or to prepare dual-layered YAG-based materials [1,7] to increase the red component in the emission, and to use transparent YAG:Ce ceramics to solve the thermal decomposition of the organic resin and to decrease the scattering [9][10][11].…”

Dual precipitating reagents-assisted deep blue-emitting borate and near-white oxide-based luminescent materials

“…The value of QY was comparable to the literature and bulk Ce-doped YAG. [80][81][82] The reason for the variation in the QY of samples may have been due to the manner of synthesis, presence of defects, distribution of Ce ions within the matrix, and calcination temperature. So, the prepared phosphor materials could be suitable candidates for lighting and display applications.…”