High-sensitivity instrumentation for spectrally-resolved optically detected X-ray absorption spectroscopy

The design use and implementation of simple but highly efficient instrumentation is described, that allows for the possibility of wavelength-resolving optically detected X-ray absorption spectra (OD-XAS) of even the weakest luminescent systems emitting in the range 380-1020 nm (1.2-3.3 eV). The instrument, based on linearly-variable interference filters, provides significant improvement in light throughput as compared with standard grating monochromators, and is used to demonstrate the power of wavelength-resolved OD-XAS in unravelling luminescence processes that are typically encountered in two common types of systems: (i) single-phase materials that possess a combination of radically different recombination pathways and (ii) materials where the recombination mechanisms are essentially invariant throughout the system, but which are chemically phase-separated on a sub-microscopic scale. (C) 2004 Elsevier B.V. All rights reserved.