What is it for?

Our FTPS setup is used to determine absorption and photocurrent spectra of various materials.

More generally, it can be used to determine the presence of some molecules or gases in air or on a substrate by analyzing their absorption/emission/transmission spectra.

For our solar applications, we have developed a specific setup for multijunction stacks in order to localize absorption into the layers and identify their specific properties. This work resulted in improved optoelectrical characterization of our tandems solar cells (see graphs below).

How does it work?

FTPS uses FTIR (Fourier Transform Infra Red) spectroscopy in order to retrieve absorption/transmission spectra. A beam of light containing many frequencies (typ. 1 to a few microns) is shined at once on the sample and the optical response is analyzed through Michelson interferometry. Fourier transform is used to transform time domain signal into the frequency domain.

FTIR is sensitive to vibration between molecules/atoms and may serve to analyze very narrow and specific absorption peaks. It offers speed, sensitivity, mechanical simplicity and built-in calibration capabilities.