Density of states of the lowest exciton band and the exciton bandwidth in coronene single crystals

The thermo-absorption spectra of coronene single crystals were investigated over the temperature range between 193 and 287 K. The density of states and the exciton bandwidth of the lowest exciton band were obtained from the thermo-absorption spectra for the 0-1 absorption band region. The density of states function of the lowest exciton band, we observed in coronene has double peaks, as is expected for the one-dimensional model. The peak-to-peak energy separation gives the exciton a bandwidth of 490 cm−1. The bandwidth obtained (490 cm−1) is larger compared with the magnitude 370 cm−1 reported for coronene at 10 K. This difference can be explained in terms of the structural phase change that occurs at 140-180 K.