Spectroscopic Analysis and Study of Charge Transport Properties for Pinacyanol Chloride-Organic Acceptor Complex as Potential Optoelectronics Material

Abstract

Organic photoconductor, pinacyanol chloride, has been studied with infrared spectroscopy because of its thermal activation energy ( E a ) and band gap ( E g = 2 E a ) lying in the infrared range. Particularly, pinacyanol chloride and its charge transfer (CT) complexes with chloranil, DDQ, TCNQ and TCNE as organic acceptors are studied in details. The CT complexes are having neither two absorption edges like ternary complex having one donor and two acceptors nor binary type with Lorentzian or Gaussian envelopes. The forbidden gap is direct band gap except chloranil complex due to increase in molecular distance and CT interaction. There is imperfect nesting and partial screening determining the mid-IR envelope, which is qualitatively different from the envelopes in binary systems. There is inverted parabola in some range below this envelope. It is explained how infrared absorption is related with the applications of such organic photoconductors in optoelectronic devices.