UV-Photopolymerization of functional materials via up-conversion of nanoparticles with NIR-Laser

 
Lanthanide-doped up-conversion nanoparticles (UCNPs) combine two of the most common radiation technologies of today. These are ultraviolet (UV) and near infrared (NIR) radiation. They are able to connect the advantages of both, such as high intensities and thermal processes of NIR lasers and the reactivity of UV photoinitiators. The UCNPs based on NaYF4 doped with Tm3+ and Yb3+ possess the capability to convert low energy radiation like NIR light around 980 nm into high energy radiation in the region of UV and blue light. The emitted light was studied by steady state and time-resolved luminescence measurements. Furthermore, the function of UV active initiators working in the NIR were tested in compositions comprising functional materials like crosslinkable monomers, UV-filter materials and pigments to cover the absorption in different spectral regions. Photoinitiators were synthesized for binding the photoactive component directly on the UCNP. First investigations of these modified particles show promising results.