A Study of Spectroscopy on TCAQ Microcrystal

UV-visible absorption spectra of 11,11,12,12-tetracyano-9,10-anthraquinodimethane (TCAQ) solution, crystal and evaporated film were, measured. The absorption spectrum of TCAQ solution in DMF had three bands at 287 nm(4.45), 310 nm(4.23) and 350 nm(4.38) respectively; that of evaporated films had one band at 370 nm and that of crystalline powder had four bands at 243 nm, 275 nm, 320 nm and 430 nm respectively. Surface photovoltage spectra of TCAQ microcrystal gave two bands at P₁ (320 nm) and P₂ (430 nm) respectively. The absorption bands were assigned and the energy levels of frontier orbitals were tentatively determined. In addition,the mechanism of hole, production and transportation in crystalline TCAQ was discussed.