Microwave assisted synthesis and characterizations of near infrared emitting Yb/Er doped fluorapatite nanoparticles

Trivalent Yb and Er doped fluoroapatite nanoparticles were prepared by a microwave assisted wet precipitation method using calcium nitrate tetrahydrate, diammonium hydrogen phosphate, ammonium fluoride and Yb, Er nitrate tetrahydrate as precursors. Well crystallized nanoparticles of rod like morphology with length and width of about 26 ± 3 and 9 ± 2 nm was obtained. Under 980 nm excitation the nanoparticles exhibit strong near infrared emission at 1532 nm with a maximum measured internal quantum yield of 74% in 3 mol% Er and 9 mol% Yb doped sample which is 26% less than the 100% radiative quantum yield predicted by Judd-Ofelt procedure. The measured quantum yield shows a linear dependence of quantum yield on Yb concentration.