Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 51: 2D Materials: Session III (joint session DS/CPP/HL)

HL 51.7: Talk

Friday, March 16, 2018, 11:30–11:45, H 2032

Evidence for low-dimensional charge transport in carbon nitride polymers — •Christoph Merschjann — Helmholtz-Zentrum-Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin — Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin

Carbon nitride (CN) polymers have gained much interest in recent years due to their potential application as both dark- and photocatalysts for various renewable-energy tasks, including water-splitting and CO₂ reduction, and others. Given their layered, van-der-Waals bound structure, these materials resemble graphite, and are hence often called "graphitic carbon nitrides" (g-C₃N₄). The main technical advantage of CNs is the abundance of their constituents (C, N, and H) and the absence of precious metals. However, compared to metal-based catalysts, the activity of CN materials is still rather low, a fact that has been largely attributed to their low conductivity. Recently, we found evidence that this low conductivity is due to polaronic hopping motions of photoexcited electrons and holes, which predominantly move vertical to the graphitic planes of the material. Backed-up by very recent transient-spectroscopy studies, we will discuss the validity of such a low-dimensional transport scenario, and its consequences for applications in catalysis as well as in organic electronics in general.