Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 27: Nanoparticles and Composite Materials II
CPP 27.6: Vortrag
Mittwoch, 13. März 2013, 16:15–16:30, H39
Absolute Photoluminescence Quantum Yield of Hexagonal β-NaYF4:Er3+, Yb3+ Upconversion Nanoparticles — •Martin Kaiser1, Würth Christian1, Resch-Genger Ute1, Hyppänen Iko2, and Soukka Tero2 — 1BAM Bundesanstalt für Materialforschung und -prüfung, Richard-Willstätter-Str. 11, 12489 Berlin — 2Department of Biotechnology, University of Turku, Tykistökatu 6A, FI-20520 Turku, Finland
Hexagonal β-NaYF4 doped with Er3+ and Yb3+ is currently the most efficient upconversion (UC) phosphor to convert near-infrared (NIR) to green light. For the design of nm-sized UC particles, there is a need for reliable spectroscopic tools for the characterization of the signal-relevant optical properties of these materials like the absolute quantum yield (QY), which equals the ratio of emitted to absorbed photons. Due to the upconverting nature of the photoluminescence and the lack of UC QY standards and conventional QY standards with absorption at 980 nm, the QY of these particles can be presently measured only absolutely. This presents a considerable challenge due to the low absorption coefficient of these materials and the power density dependence of QY. We present here a custom-designed integration sphere setup equipped with a power-stabilized 980 nm-laser diode for spectrally resolved and power density-dependent measurements of the absolute UC QY as well as the transmission and reflection of UC materials in suspension and in the solid state. The characterization of this setup is detailed as well as first QY of nm-sized β-NaYF4:Er3+, Yb3+ in different environments.