Quantum yield (QY) is one of the most important quantitative properties of a luminescent sample and robust ways to measure it are essential in the application of luminescence techniques. In this project, the task group will perform an inter-laboratory comparison of the two main methods for QY measurements, the classical relative method based on standards, and the absolute method using integrating spheres which has recently gained popularity.
A previous IUPAC project (www.iupac.org/project/2004-021-1-300; see Pure Appl. Chem. 2011, 83, 2213-2228) has clearly shown a shortage of standards for relative QY measurements of solutions. Recently, absolute measurements have become more popular as a result of the wider availability of integrating sphere equipment, but their reliability is still to be established.
Further standards are needed to fully cover the wavelength range of interest, from ~250 to ~1000 nm. Preferred reference compounds have broad and featureless absorption spectra and have proven emission quantum yields independent of the excitation wavelength. The reference values should preferably be those of air-equilibrated samples. The second purpose of the project is to establish the variability of independent QY measurements in different laboratories. Therefore ten laboratories world-wide have been invited to take part in this test. The laboratories are well-equipped and experienced, but are not specialists or method developers in the field. We are interested in find out what is the current practice in a normal good laboratory.
Twenty-two samples have been selected in the first stage of the project. For eight of these samples, the quantum yields are considered very well established. The other samples have been measured against these eight standards, or were measured using integrating spheres. The results of the measurements are currently being collected.
The outcomes of this new project will provide insight into the reproducibility and inter-laboratory variability of QY measurements using the two methods and detail an extended set of standards and protocols for QY measurement.
For further information, contact the Task Group Chair Fred Brouwer <a.m.brouwer@uva.nl>
©2015 by Walter de Gruyter Berlin/Boston
