Biexponentiality charge recombination

Steady-state fluorescence spectra recorded after the addition of the NDI or PM I acceptor to the bisporphyrin tweezer ( rrl = 660 nm), demonstrated substantial quenching (75%) with increasing quantities of the NDI or PM I acceptors. Time-resolved emission spectra recorded in toluene for the complex 26 were biexponential containing a dominant short-lived CS components (80 ps, -95%) attributed to photoinduced ET from donor porphyrin to NDI, and a minor long-lived component (Ins, 5%). The lifetime of the dominant short-lived CS state is increased two- to threefold relative to covalently linked systems under similar conditions of solvent, donor-acceptor distance and thermodynamics [37]. Charge recombination rates from 1.4 to 3.8 x 1()9s 1 were observed, depending on whether the NDI or PM I acceptor was bound within the cavity. 

Charge injection and charge recombination rate constants for details about light source, light intensity, and excitation wavelength see the reference. The kinetic models used to obtain the rate constants varies first-order, biexponential, multiexponential or second-order kinetic models are used see references for detail. Listed units are not suitable for those who use second-order kinetic models. 

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