Nanosecond and sub-nanosecond time-resolved fluorescence spectroscopy at interfaces

It is well-known that the behavior of molecules at interfaces is of critical importance in areas ranging from energy conversion, energy transfer, and chromatography to catalysis and chemical sensing. In this Review we focus on the use of nanosecond and sub-nanosecond time-resolved fluorescence spectroscopy as a tool to probe the photophysics and dynamics of fluorescent centers adsorbed at or covalently attached to various interfaces under ambient conditions and/or in contact with solution. By using time-resolved fluorescence spectroscopy in concert with interfacially selective detection one is able to access the underlying kinetics (and hence mechanisms) associated with these surface bound molecules. In turn these results provide key insights into how the surface controls/modulates the behavior and thus performance of these molecules. For completeness and ease of discussion, this Review contains a complete theory section on time- and frequency-domain fluorescence intensity and anisotropy measurements at interfaces. This Section is followed by literature examples that are divided into non-biochemical and biochemical applications of time-resolved intensity and anisotropy decay measurements at interfaces.