Luminescent, Scintillation, and Photoconversion Properties of Micro‐Pulling‐Down‐Grown Single Crystals of Ce3+‐Doped Gd3−xLuxAl5−yGayO12 Garnets

Herein, the development of phosphor‐converted white light‐emitting diodes (pc‐WLED) and scintillators based on the crystals of Ce3+‐doped multicomponent garnets, grown by the micro‐pulling‐down (MPD) method is studied. The combined technique of the “bandgap engineering” and “positioning of Ce3+ 5d‐levels” is applied to the crystals of Gd3−xLuxAl5−yGayO12 (x = 0–1.5 and y = 2–3) mixed garnets for improving their color‐rending properties in pc‐WLEDs application as well as their scintillation figure of merit. The absorption, cathodoluminescence, photoluminescence, photoconversion (PC), and also the scintillation light yield and scintillation decay time measurements under excitation by α‐particles of 239Pu radioisotope are used for the characterization of the crystals. Among all the investigated garnet compounds, the best photoconverting properties are observed in Gd3−1.5Lu0−1.5Al5−yGayO12:Ce crystals at x = 0–1.5 and y = 2.5–3. Meanwhile, the best scintillation characteristics are found in Gd3−xLuxAl5−yGayO12 crystals at x = 0–1.5 and y = 2–2.5. The optimization of Gd3+ and Ga3+ contents in Gd3−xLuxAl5−yGayO12:Ce mixed garnets allows obtaining single crystals using micro‐pulling‐down (MPD) or other grown method with predicted optical properties for photoconversion and scintillation applications. Namely, a large number of uniform white light‐emitting diode (WLED) converters with suitable sizes can be easily created from the crystals grown using the MPD method due to their specific form.