Measurement Against a Standard in Solution

The most commonly utilised way to measure the unknown emission efficiency of a lanthanide ion complex x is by comparison to a standard ST of known emission efficiency. 

For A 0.05 the terms involving the factorials are below 5%, so that for dilute solutions with very low absorbance they can be safely ignored and Equation 2.6 simplifies to 

If the emission quantum yields are measured with sample and standard in different solvents, the differences in refractive index should be corrected by using Equation 2.9. 

Common standards used for these measurements are summarised in Table 2.1. 

If measuring at A 0.05 is impractical, either because the metal ion decomplexes at the concentration needed, or sensitisation is not observed at 2 - for this low absorbance, measurements of a series of solutions of different concentrations can be done instead. Samples with different concentrations are prepared and the integrated emission spectra for each are plotted as a function of sample absorbance. Similarly, integrated emission spectra for a series of solutions of standard at different concentrations are plotted as a function of their absorbance. The slopes m of the obtained lines are then used to calculate the emission efficiency of the sample, following Equation 2.10. 

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Luminescence of Lanthanide Ions In Coordination Compounds and Nanomaterials 2.3.1 Measurement Against a Standard in Solution... 

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