The study of aggregation dynamics of conjugated polymer solutions in UV-vis absorbance spectra by considering the changing rate of average photon energy.

The changing rate of average photon energy ('Eave) can describe the UV-vis absorbance spectra over a wavelength range. During the aggregation process of poly (3-hexylselenophene) (P3HS) and poly (3-hexylthiophene) (P3HT) solutions that form J-aggregates, 'Eave always decrease and the relationship between 'Eave and time is an exponential model. 'Eave can predict the time when the aggregation process is completed or how far the aggregation process is from the completion. Hansen Solubility Parameter (HSP) of the solvent can be used to predict 'Eave of some conjugated polymer solutions without doing experiments. ''Eave (changing rate of 'Eave at the beginning of the aggregation process) has been calculated to reflect the overall changing trend of 'Eave and reflects the compatibility between solvent and solute. Therefore, 'Eave is suitable to describe the aggregation dynamics of conjugated polymer solutions by evaluating the aggregation process in UV-vis absorbance spectra.