Enhanced upconversion emission in colloidal (NaYF4:Er3+)/NaYF4 core/shell nanoparticles excited at 1523 nm
2014 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 39, no 6, 1386-1389 p.Article in journal (Refereed) Published
In this work, we report on efficient visible and near-IR upconversion emissions in colloidal hexagonal-phase core/shell NaYF4:Er3+/NaYF4 nanoparticles (similar to 38 nm) under IR laser excitation at 1523 nm. Varying amounts of Er3+ dopants were introduced into the core NaYF4:Er3+ nanoparticles, revealing an optimized Er3+ concentration of 10% for the highest luminescent efficiency. An inert epitaxial shell layer of NaYF4 grown onto the core of the NaYF4:Er3+ 10% nanoparticle increased its upconversion emission intensity fivefold due to suppression of surface-related quenching mechanisms, yielding the absolute upconversion efficiency to be as high as similar to 3.9 +/- 0.3% under an excitation density of 18 W/cm(2). The dependence of the intensity of upconversion emission peaks on laser excitation density in the core/shell nanoparticle displayed "saturation effects" at low excitation density in the range of 1.5-18 W/cm(2), which again demonstrates high upconversion efficiency.
Place, publisher, year, edition, pages
2014. Vol. 39, no 6, 1386-1389 p.
Core/shell nanoparticles, Excitation density, Luminescent efficiency, Quenching mechanisms, Saturation effects, Shell layers, Up-conversion efficiency, Up-conversion emission Efficiency, Laser excitation, Nanoparticles
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-144363DOI: 10.1364/OL.39.001386ISI: 000332943800016ScopusID: 2-s2.0-84897438402OAI: oai:DiVA.org:kth-144363DiVA: diva2:713409
QC 201404232014-04-232014-04-222014-04-23Bibliographically approved