Giant photo-effect in proton transport through graphene

Abstract

Graphene has recently been shown to be permeable to thermal protons, nuclei of hydrogen atoms, which sparked interest in its use as a proton-conducting membrane in relevant technologies. Here we report that proton transport through graphene can be enhanced strongly by iluminating it with visible light. Using electrical measurements and mass spectrometry, we find a photoresponsivity of ∼10<sup>4</sup> A W<sup>-1</sup>, which translates into a gain of ∼10<sup>4</sup> protons per photon, with response times in a microsecond range. These characteristics are competitive with thos of state-of-the-art photodetectors based on electron transport using silicon and novel two-dimensional materials. The photo-proton effect can be important for graphene's envisaged use in fuel cells and hydrogen isotope separation. Our observations can also be of interest for other applications such as light-iduced water splitting, photo-catalysis and novel photodetectors.

Recent Progress on Two-Dimensional Materials

“…One strategy is to tune the electrons distribution on 2D materials using proton-binding metal nanoparticles decorated on 2D materials to form heterostructures 1565 . The built-in electric field at the materialnanoparticle interface can be further enhanced if illuminated with visible light, leading to a graphene areal proton conductance above 2 S•cm −2 at room temperature 1584 .…”