Semiconductivities and Charge Transfer Spectra of Solid Molecular Complexes of 1,3,5-Trinitrobenzene

A series of solid complexes of aromatic hydrocarbons and amines, with 1,3,5-trinitrobenzene as the common electron acceptor, were prepared. These complexes were of the loose molecular complex type, and the charge transfer bands were observed with the solid complexes, which showed only small red-shifts from the corresponding bands of the solutions. These solid complexes are poor semiconductors, and the energy gap for the excitation to the conduction state is relatively large, and is nearly coincident with the energy for the charge transfer excitation. From these results, it has been suggested that the charge transfer state in the crystal may not be very different from the corresponding state in the isolated (1 : 1)-complex in the solution. The relation between the charge transfer state and the conduction state has been discussed, and a probable model for the formation of a charge carrier has been suggested.