Electronic Spectra of Perylene and Coronene Evaporated Films as a Function of Their Crystallinity

The absorption spectra of evaporated thin films of perylene and coronene have been studied as a function of their crystallinity. The amorphous films deposited on a low-temperature substrate in vacuo gave rise to “molecular” spectra which are very different from those of the polycrystalline films. The absorption spectra of amorphous films gradually changed with an increase in the substrate temperature to become similar to those of the polycrystalline films.