Abstract
Fluorescence is an important property when determining
the colour and appearance of a solid opaque material.
Relative and absolute measurements of angular
fluorescence spectra and quantum yield are important in
many industrial fields including paper, textile and also
in medical industry. The uncertainty of the measurements
is naturally dependent on the uncertainty of the
reference standards and therefore it is important to have
high-accuracy calibration instruments capable of absolute
measurements.
Lambertian behaviour of fluorescent emission in solid
amorphous materials is a commonly made assumption.
Deviation from this behaviour has been shown [1][2] by
using goniometric measurements of fluorescence
[3][4].This finding is significant since most commercial
and research instruments are limited to fixed geometry
measurements and usually rely on the assumption of
Lambertian emission of fluorescence. This may result in
errors in inter geometry measurements of fluorescence and
also absolute quantum yield estimations. To address these
challenges, either more Lambertian standard materials or
reliable methods to correct for these effects are needed.
Figure 1. The relative luminescent radiance factors ?L
and reflected radiance factors ?R at peak emission
wavelength for each sample and reflected wavelength (380
nm) respectively.
In this work bispectral luminescent radiance factors and
reflected radiance factors of a number of commercially
available fluorescence standards and a novel standard
material candidate have been measured in a wavelength
range from 380 nm to 700 nm with an uncertainty (k=2) of
1%. The angular distribution of the emitted radiation
from the standard materials is in addition to being
non-Lambertian also shown to be different from the
angular distribution of reflected radiation as seen on
Figure 1. The novel sample is shown to exhibit more
Lambertian emission and reflection behaviour than the
commercially available standard materials. In addition
the effects of the angular profiles of measured radiation
on the absolute quantum yield estimation of the materials
are shown.
Original language | English |
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Publication status | Published - 2015 |
Event | PTB International Summer School on Metrology - Drübeck, Germany Duration: 24 Aug 2015 → 28 Aug 2015 |
Course
Course | PTB International Summer School on Metrology |
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Country/Territory | Germany |
City | Drübeck |
Period | 24/08/15 → 28/08/15 |
Keywords
- fluorescence
- goniometrical
- uncertainty
- measurement