Multiscale Charge Transport in van der Waals Thin Films: Reduced Graphene Oxide as a Case Study
Artikel i vetenskaplig tidskrift, 2021

Large area van der Waals (vdW) thin films are assembled materials consisting of a network of randomly stacked nanosheets. The multiscale structure and the two-dimensional (2D) nature of the building block mean that interfaces naturally play a crucial role in the charge transport of such thin films. While single or few stacked nanosheets (i.e., vdW heterostructures) have been the subject of intensive works, little is known about how charges travel through multilayered, more disordered networks. Here, we report a comprehensive study of a prototypical system given by networks of randomly stacked reduced graphene oxide 2D nanosheets, whose chemical and geometrical properties can be controlled independently, permitting to explore percolated networks ranging from a single nanosheet to some billions with room-temperature resistivity spanning from 10-5 to 10-1 ω·m. We systematically observe a clear transition between two different regimes at a critical temperature T*: Efros-Shklovskii variable-range hopping (ES-VRH) below T∗ and power law behavior above. First, we demonstrate that the two regimes are strongly correlated with each other, both depending on the charge localization length ζ, calculated by the ES-VRH model, which corresponds to the characteristic size of overlapping sp2 domains belonging to different nanosheets. Thus, we propose a microscopic model describing the charge transport as a geometrical phase transition, given by the metal-insulator transition associated with the percolation of quasi-one-dimensional nanofillers with length ζ, showing that the charge transport behavior of the networks is valid for all geometries and defects of the nanosheets, ultimately suggesting a generalized description on vdW and disordered thin films.

van der Waals thin films

charge transport


graphene-based materials


composite materials

conductive polymers


Alessandro Kovtun

Istituto per la Sintesi Organica e la Fotoreattività (ISOF-CNR)

Andrea Candini

Istituto per la Sintesi Organica e la Fotoreattività (ISOF-CNR)

Anna Vianelli

MISTER Smart Innovation

Alex Boschi

Istituto per la Sintesi Organica e la Fotoreattività (ISOF-CNR)

Simone Dell'Elce


Marco Gobbi


Basque Foundation for Science (Ikerbasque)

Université de Strasbourg

Kyung Ho Kim

Royal Holloway University of London

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Samuel Lara Avila

Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik

Paolo Samorì

Université de Strasbourg

Marco Affronte

Dipartimento di Scienze Fisiche

A. Liscio

Consiglo Nazionale Delle Richerche

Vincenzo Palermo

Istituto per la Sintesi Organica e la Fotoreattività (ISOF-CNR)

Chalmers, Industri- och materialvetenskap, Material och tillverkning

ACS Nano

1936-0851 (ISSN) 1936-086X (eISSN)

Vol. 15 2 2654-2667


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