Voltammetric investigation for electron-transfer characteristics of organic semiconductors

Abstract

Two voltammertic techniques, cyclic voltammetry (CV) and chronocoulometry (CC), were employed to investigate the redox characteristics of two organic semiconductors in organic light-emitting diodes (OLED), fac-tris(2-phenylpyridine)iridium (Ir(ppy)3) and N, N'-di(1-naphthyl)-N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB). The electron-transfer characteristics including of oxidation formal potentials (Eo'), diffusion coefficients (Do), electron-transfer rate constants (ko') were estimated by the combination of CV and CC measurements. The energy level of the highest-occupied molecular-orbital (EHOMO) was also found by quantitative relationship between the oxidation potential and the ionization energy.