Development of novel scintillation and photo-conversion materials based on Gd3(Sc,Al,Ga)5O12:Ce single crystals grown by micro-pulling-down method

Luminescence, scintillation and photoconversion properties of Gd3Al5−x−yScxGayO12:Ce crystals, grown by the micro-pulling-down method, were studied upon substitution of Al for Sc3+ and Ga3+ in the x = 1–2;y = 1–3 ranges. A decrease of the band gap and crystal field strength occurs in these garnets with increasing Sc3+ and Ga3+ content, resulted in blue-shift and reduced thermal stability of Ce3+ emission. Lowering of the scintillation light yield of crystals by two times and scintillation decay kinetic acceleration from 97 to 27 ns is observed at increasing Ga content in the y = 1–3 range. Sc and Ga admixing increases the number of deep charge traps, which additionally deteriorate of crystals scintillation performance. Application of Gd3Al5−x−yScxGayO12:Ce crystals as phosphor converters of white LED was considered. Increasing the Sc3+ and Ga3+ content in crystals leads to linear blue shift of the converter emission and results in increasing the color temperature of LEDs from neutral to could white light.