Marine diatoms as optical chemical sensors: A time-resolved study

Marine diatoms are microscopic algae living in aquatic environment; their skeleton, made of amorphous silica, possesses a complex geometrical structure that presents holes on different length scales in a fractal-like fashion, achieving a high surface-to-volume ratio and making them good candidates for gas detecting purposes. Indeed, different gas species can influence diatoms' photoluminescence emission according to their different polarizing abilities. In particular, to exploit marine diatoms as optical nitrogen dioxide sensors and in order to get a better insight on the nature of the photoluminescence quenching process induced by the gas molecules, continuous-wave and time-resolved photoluminescence studies have been carried out, showing that nitrogen dioxide affects only the photoluminescence yield without altering the dynamics of the recombination process. (C) 2007 Elsevier B.V. All rights reserved.