Self-absorption and luminescence quantum yields of dye-zeolite L composites

Electronic absorption and fluorescence spectra based on transmission measurements of thin layers obtained from new perylene-zeolite L composites and new dye1,dye2-zeolite L sandwich composites, the latter acting as antenna systems, have been investigated and analyzed. The influence of extra-and intraparticle self-absorption on the spectral shape and fluorescence quantum yield is discussed in detail. Due to its intraparticle origin, self-absorption and re-emission can often not be avoided in organized systems such as dye-zeolite L composites where a high density of chromophores is a prerequisite for obtaining the desired photophysical properties. We show, however, that it can be avoided or at least minimized by preparing dye1,dye2-zeolite L sandwich composites where donors are present in a much larger amount than the acceptors because they act as antenna systems.