International Journal of Applied Research

Abstract
The ternary charge transfer complexes of the well-known organic donor namely diphenyl-p-phenylene-diamine (DPPD) have been studied with FTIR spectroscopy. There are two absorption edges – one at the Peierls gap (0.225 eV) and the other at the half of it, i.e. at 0.1125 eV. There is non-universal additional shrinkage of the second gap due to electron-electron scattering. The third gap at 0.056 eV is not observed as observed in the case of benzidine ternary complexes. Rather a free-carrier absorption revealing scattering of charge carriers by acoustic phonons is observed in 700-1000 cm-1 range. This also shows that bipolarons are the charge carriers in DPPD ternary complexes.