Bright Infrared‐to‐Ultraviolet/Visible Upconversion in Small Alkaline Earth‐Based Nanoparticles with Biocompatible CaF 2 Shells

Fischer, Stefan; Siefe, Chris; Swearer, Dayne F.; McLellan, Claire A.; Alivisatos, A. Paul; Dionne, Jennifer A.

doi:10.1002/anie.202007683

Title: Bright Infrared‐to‐Ultraviolet/Visible Upconversion in Small Alkaline Earth‐Based Nanoparticles with Biocompatible CaF ₂ Shells

Journal Article · Wed Sep 23 00:00:00 EDT 2020 · Angewandte Chemie (International Edition)

DOI:https://doi.org/10.1002/anie.202007683· OSTI ID:1786193

Fischer, Stefan ^[1];

^[1]; Swearer, Dayne F. ^[1]; McLellan, Claire A. ^[1]; Alivisatos, A. Paul ^[2];

^[1]

Department of Materials Science and Engineering Stanford University 496 Lomita Mall Stanford CA 94305 USA
Materials Science Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA, Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA, Department of Materials Science and Engineering University of California, Berkeley Berkeley CA 94720 USA, Kavli Energy Nanoscience Institute Berkeley CA 94720 USA

Abstract Upconverting nanoparticles (UCNPs) are promising candidates for photon‐driven reactions, including light‐triggered drug delivery, photodynamic therapy, and photocatalysis. Herein, we investigate the NIR‐to‐UV/visible emission of sub‐15 nm alkaline‐earth rare‐earth fluoride UCNPs (M _{1− x} Ln _x F _{2+ x ,} MLnF) with a CaF ₂ shell. We synthesize 8 alkaline‐earth host materials doped with Yb ³⁺ and Tm ³⁺ , with alkaline‐earth (M) spanning Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. We explore UCNP composition, size, and lanthanide doping‐dependent emission, focusing on upconversion quantum yield (UCQY) and UV emission. UCQY values of 2.46 % at 250 W cm ⁻² are achieved with 14.5 nm SrLuF@CaF ₂ particles, with 7.3 % of total emission in the UV. In 10.9 nm SrYbF:1 %Tm ³⁺ @CaF ₂ particles, UV emission increased to 9.9 % with UCQY at 1.14 %. We demonstrate dye degradation under NIR illumination using SrYbF:1 %Tm ³⁺ @CaF ₂ , highlighting the efficiency of these UCNPs and their ability to trigger photoprocesses.

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Sponsoring Organization:: USDOE

OSTI ID:: 1786193

Journal Information:: Angewandte Chemie (International Edition), Journal Name: Angewandte Chemie (International Edition) Vol. 59 Journal Issue: 48; ISSN 1433-7851

Publisher:: Wiley Blackwell (John Wiley & Sons)Copyright Statement

Country of Publication:: Germany

Language:: English

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