TY  - JOUR
A1  - Frenzel, F.
A1  - Fiedler, S.
A1  - Bardan, A.
A1  - Güttler, Arne
A1  - Würth, Christian
A1  - Resch-Genger, Ute
T1  - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
JF  - Analytical chemistry
N2  - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW  - Quality assurance
KW  - Fluorescence
KW  - Nano
KW  - Particle
KW  - Quantum yield
KW  - Characterization
KW  - Silica
KW  - Scattering
KW  - Uncertainty
KW  - Film
KW  - Pphosphor
KW  - YAG:Ce
KW  - LED
KW  - Converter material
KW  - Solid material
KW  - Polymer
KW  - Composite material
KW  - Advanced material
PY  - 2025
UR  - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO  - https://doi.org/10.1021/acs.analchem.4c06726
SN  - 1520-6882
SP  - 1
EP  - 8
PB  - ACS Publications
AN  - OPUS4-63830
LA  - eng
AD  - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER  -