Potical Energy Gap and Below Gap Optical Absorption of Fullerene Films Measured By Constant Photocurrent Method and Photothermal Deflection Spectroscopy

CPM spectra of the fullerene film was measured to obtain the below gap absorption. The optical energy gap E(o) was obtained by using the Tauc's plots. E(o) did not change so much with the intercalated impurities. The absorption due to intercalated impurities was found below 1.6eV.