Paper
21 August 2020 Surface engineering of small and bright upconversion nanoparticles providing chemical and colloidal stability in biological media
Angelina Hirmer, Susanne Märkl, Alexandra Schroter, Thomas Hirsch
Author Affiliations +
Abstract
One of the main challenges for any applications of nanoparticles in biological media is to control the surface chemistry of the nanomaterials preventing chemical disintegration and agglomeration. When the surface effects dominate over the bulk properties, which is especially the case for small lanthanide doped NaYF4 nanocrystals, the surface capping significantly affects the brightness of the upconversion luminescence. Here, we present the influence of commonly used buffer systems such as N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid) (HEPES) and 2-(N morpholino)ethanesulfonic acid hydrate (MES) on the stability and surface chemistry of NaYF4:Yb,Er nanoparticles. The results indicate that surface modifications by ligand exchange provide a simple strategy for attaching many different ligands to the particle surface and render them water dispersible. Nevertheless, one has to take into account that particle surfaces are not fully covered and certain buffers, especially those with sulfo groups, may alter the surface chemistry with time.
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Angelina Hirmer, Susanne Märkl, Alexandra Schroter, and Thomas Hirsch "Surface engineering of small and bright upconversion nanoparticles providing chemical and colloidal stability in biological media", Proc. SPIE 11467, Nanoengineering: Fabrication, Properties, Optics, Thin Films, and Devices XVII, 114670X (21 August 2020); https://doi.org/10.1117/12.2568758
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Particles

Nanoparticles

Upconversion

Luminescence

Lanthanides

Nanoparticle functionalization

Back to Top