Light emission from ultrathin organic films grown by in-vacuo electrospray deposition

X-ray excited optical luminescence (XEOL) and optically-detected x-ray absorption spectroscopy (ODXAS) have been applied in parallel to correlate light emission and local chemical structure in thin films of polymer/dye blends grown by in-vacuo electrospray deposition. This technique enables soft materials to be grown in uniform layers from solution in vacuum and studied by soft x-ray and electron-based techniques. Growth of polymers, dyes and blends in vacuum has been shown to be more uniform than growth in atmosphere and they can be grown with sub-nm thickness precision. Soft x-ray excitation enables luminescence from wide-gap materials to be probed over a wider energy range than is often possible with laser excitation and the tuneability of the soft x-rays provides chemical and electronic information on the same sampling volume. Using this approach, x-ray excited light emission from dye molecules has been shown to be significantly modified when the molecules are incorporated into a wide-gap polymer matrix. ODXAS measurements relate the source of light emission to the local bonding within the thin film.