The Swiss Federal Institute of Technology EPFL has developed a concept of an integrating sphere for the absolutes measures of the quantum efficiency for small quantities of solid samples or solutions (60 µL).
The GMP G8 Integrating Sphere allows for the determination of Quantum Yield with a repeatability within of a few percent and a precision over 95%.
Quantum yield is frequently used to characterize luminescent material. It corresponds to the ratio between the number of emitted photons at a given wavelength, usually in the UV-visible region, and the number of absorbed photons. Using an integrating sphere is a classical approach to that measurement. However, greatest care must be given to the signal to noise ratio, to retro diffusion of the excitation light, to possible contamination of the sphere when manipulating the sample and to the critical calibration process. Designed by qualified and experienced specialists in Spectroscopy, the GMP G8 Sphere addresses these concerns. The result is a neat, practical and easy to use device intended for high precision and reproducibility measurements.
- Small diameter of the sphere for a higher intensity emission signal.
- Very small quantities of sample required, whether solid (powders) or liquid (e.g. 60 μl for solutions).
- Possibility to adjust the position of the sample vertically in order to optimize the intensity of the emission signal.
- Two emission windows at +90° and -90°: the same measurement setup applies to calibration and measurement, only thesphere pivots by 180°
- Two rectractable baffles: pushed in they protect the detector from direct radiation; pulled out, they allow the recording of the emission spectrum without modifying the measurement setup.
- Quartz insert to receive the capillary tube containing the sample, thus avoiding contamination inside the sphere while sample is manipulated. So, no need to open the sphere.
- Measurement of very low quantum yields are possible, even in the near IR range (down to 0.02%).
- Samples of air sensitive products which are very difficult to measure, may be inserted into sealed capillary tubes.