Organic-Inorganic Charge Transfer Complex with Charge Modulation after Electrical Pre-biasing

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)37384-37390
Journal / PublicationACS applied materials & interfaces
Issue number33
Online published24 Jul 2020
Publication statusPublished - 19 Aug 2020


Several breakthroughs in organic optoelectronic devices with new applications and performance improvement have been made recently by exploiting novel properties of charge transfer complexes (CTCs). In this work, a CTC film formed by coevaporating molybdenum(VI) oxide and pentacene (MoO3:pentacene) shows a strong dipole of 2.4 eV with direction controllability via pre-biasing with an external voltage. While CTCs are most widely known for their much red-shifted energy gaps, there is so far no report on their controllable dipoles. By controlling this dipole with an electrical pre-bias in a MoO3:pentacene CTC based device, current changes over 2 orders of magnitude can be achieved. Kelvin probe force microscopy further confirms that surface potential of the MoO3:pentacene film can be modulated by an external electric field. It is shown for the first time that a dipole of controllable direction can be set up inside a CTC layer by pre-biasing. This concept is further tested by incorporating the CTC layer in organic photovoltaic (OPV) devices. It was demonstrated that by pre-biasing the OPV devices in different directions, their open circuit voltages (Voc) can be significantly tuned via the built-in potentials.

Research Area(s)

  • charge modulation, charge transfer complex, dipole, organic−inorganic, pre-bias