In situ synthesis of a highly crystalline Tb-doped YAG nanophosphor using the mesopores of silica monoliths as a template

Abstract

This report describes the first synthesis of a highly crystalline YAG:Tb nanophosphor inside the pores of a mesoporous silica monolith (MSM).

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“…Only when protective matrices are used during the calcination, individual nanocrystals are formed. , Starting from a sol–gel synthesis, the YAG precursor is first combusted − (sometimes in a microwave oven − ) and then calcined in an oven. The matrix approach made use of an oven, without separate combustion step . The resulting particles are either large crystals ,,, or sintered materials. − ,, The solvothermal procedure is a one-step synthesis to yield either agglomerated − or individual nanocrystals. ,− One paper reports subsequent calcining in a matrix, yielding large crystals …”

“…The matrix approach made use of an oven, without separate combustion step . The resulting particles are either large crystals ,,, or sintered materials. − ,, The solvothermal procedure is a one-step synthesis to yield either agglomerated − or individual nanocrystals. ,− One paper reports subsequent calcining in a matrix, yielding large crystals …”

“…Above, we discussed the use of a protective LiCl or K 2 SO 4 matrix during the calcination treatment to prevent sintering of the YAG (precursor) particles made via a coprecipitation procedure. For the sol–gel synthesis route, another matrix material is proposed by Aboulaich et al: mesoporous silica. This porous material was impregnated by a solution of YCl 3 , TbCl 3 , and Al-isopropoxide in isopropanol and subsequently calcined for 3 h at 1100 °C (Figure A).…”

“…(B) Transmission electron microscopy image of resulting YAG particles. Reprinted (adapted) with permission from ref (Copyright 2015 The Royal Society of Chemistry).…”

“…99 The resulting particles are either large crystals 86,91,97,98 or sintered materials. [87][88][89][90][91][92][93][94]96,99 The solvothermal procedure is a one-step synthesis to yield either agglomerated 100−103 metal salts and urea is used, which then sinter after calcination at 1200 °C for 4 h to individual particle sizes of >50 nm. Baranwal et al 83 start from hydroxide precursors and report that a calcination time of 10 h is needed to crystallize YAG at 900 °C, while 5 h is sufficient at 1000 °C.…”