Dimensionality and temperature dependence of the radiative lifetime of J-aggregates with Davydov splitting of the exciton band

The temperature dependence of the radiative exciton lifetime (τrad) of J-aggregates of 3,3′-bis(sulfopropyl)-5,5′-dichloro-9-ethylthiacarbocyanine (THIATS) characterized by a Davydov splitting of the exciton band has been determined over the temperature range from 4.2 to 130 K. The Davydov splitting of the exciton band was taken into account during the calculation of the coherent length (Nc) from the values of τrad. The temperature dependence of τrad(T) in units of (Nc)−1 was compared to that for PIC aggregates. In contrast to the observations for the PIC J-aggregates [Potma and Wiersma, J. Chem. Phys., 108 (1998) 4894] the τrad(T) of J-aggregates of THIATS can be rationalized within the framework of a 1-D exciton model.