Sr2SiO4:Sm3þ phosphor weresynthesizedat600 1C bythe
sol–gel routeusingTEOSasaprecursorandcharacterizedbyX-
raydiffraction(XRD)andphotoluminescence(PL)techniques.
Fromtheemissionspectroscopythe 4G5/2-6H9/2 (ED) transitions
of Sm3þ ions weremoreintensethan 4G5/2-6H5/2 (MD) transi-
tion, indicatingtheasymmetricnatureofSm3þ ion inSr2SiO4 host
matrix. Fluorescencelifetimemeasurementshowedmonoexpo-
nential behaviorforSm3þ in strontiumsilicatewithalifetime
valueof2.23ms.Basedonlifetimeandemissionspectra,itcanbe
inferredthatSm3þ occupies 9-coordinatedSr2þ in strontium
silicate. Fromcrystal field splittingitwasinferredthattheactual
site symmetryofSm3þ is verylikelyreducedtoaC3v, duetothe
difference ofionicradiusandchargeimbalancebetweenSm3þ
and Sr2þ. ConcentrationquenchingofthePLsignalintensitywas
observed foradopantionconcentrationofmorethan1mol%.
Fromthis,thecriticalenergytransferdistanceofSm3þ was
calculated tobe21Åandthemechanismofconcentration
quenchingwasdeterminedtobethedipole–dipole interaction.
At higherconcentration(4x¼ 0.01);twolifetimevaluesare
observed forSm3þ one oftheorderof500 ms andtheotherofthe
order 2.3ms.Boththesespeciesarepresentin9-coordinated
environment,butspecieshavingrelativelylowerlifetimevalueis
nearer tochargecompensatingdefectsandtheonehavinghigher
lifetime isfarofffromchargecompensatingdefects.