X-ray Excited Optical Luminescence (XEOL)

23 October, 2023

A new experiment set-up, allowing for the measurement of emission spectra under X-ray beam irradiation, is now available at the end station of BM08-XAFS/XRF. 

X-ray Excited Optical Luminescence (XEOL) is an X-ray photon in/optical photon out technique that is related to the conversion of the X-ray energy absorbed by the materials to optical photons, involving multi-step energy transfer cascade processes. XEOL is often used together with XANES to reveal the electronic structure and optical properties of the system of interest, such as rare earth down conversion phosphors, quantum confined semiconductors, heterogeneous materials etc., and is applied in display/lighting technologies (TV, smartphone and LED lamps), scintillators, rechargeable batteries and energy conversion devices (photovoltaic cells). Combined with XAFS and XRF at BM08-XAFS/XRF beamline, the new capability enables users to probe optical channels in materials, and directly correlate them with the chemical composition, oxidation state/symmetry site, coordination geometry, and local atomic structure order of the photoabsorbers. The set-up can also accommodate a LASER source - provided by the users - allowing to measure emission spectra under simultaneous LASER excitation. This experimental setup was financially supported by International Atomic Energy Agency (IAEA).

General view of the XEOL experimental setup at BM-08 XAFS/XRF beamline. Sample environment with optical fiber for collecting the luminescence signals (right) and Spectrometer for acquiring the emission spectra under irradiation with X-ray beam (left).