title: Electrohydrodynamic-assisted Assembly of Hierarchically Structured, 3D Crumpled Nanostructures for Efficient Solar Conversions.
abstract: The tantalizing prospect of harnessing the unique properties of graphene crumpled nanostructures continues to fuel tremendous interest in energy storage and harvesting applications. However, the paper ball-like, hard texture, and closed-sphere morphology of current 3D graphitic nanostructure production not only constricts the conductive pathways but also limits the accessible surface area. Here, we report new insights into electrohydrodynamically-generated droplets as colloidal nanoreactors in that the stimuli-responsive nature of reduced graphene oxide can lead to the formation of crumpled nanostructures with a combination of open structures and doubly curved, saddle-shaped edges. In particular, the crumpled nanostructures dynamically adapt to non-spherical, polyhedral shapes under continuous deposition, ultimately assembling into foam-like microstructures with a highly accessible surface area and spatially interconnected transport pathways. The implementation of such crumpled nanostructures as three-dimensional rear contacts for solar conversion applications realize benefits of a high aspect ratio, electrically addressable and energetically favorable interfaces, and substantial enhancement of both short-circuit currents and fill-factors compared to those made of planar graphene counterparts. Further, the 3D crumpled nanostructures may shed lights onto the development of effective electrocatalytic electrodes due to their open structure that simultaneously allows for efficient water flow and hydrogen escape.
authors.affiliation: School of Engineering, University of California, Merced, California 95343, USA.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Ishihara
authors.affiliation: School of Engineering, University of California, Merced, California 95343, USA.|Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, California 94720, USA.
authors.forename: Yen-Chang
authors.initials: YC
authors.lastname: Chen
authors.affiliation: School of Engineering, University of California, Merced, California 95343, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: De Marco
authors.affiliation: Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, California 94720, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Lin
authors.affiliation: Department of Electrophysics, National Chiao Tung University, Taiwan.
authors.forename: Chih-Meng
authors.initials: CM
authors.lastname: Huang
authors.affiliation: School of Engineering, University of California, Merced, California 95343, USA.
authors.forename: Vipawee
authors.initials: V
authors.lastname: Limsakoune
authors.affiliation: Department of Electrophysics, National Chiao Tung University, Taiwan.
authors.forename: Yi-Chia
authors.initials: YC
authors.lastname: Chou
authors.affiliation: Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA.|California NanoSystems Institute, California 90095, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Engineering, University of California, Merced, California 95343, USA.
authors.forename: Vincent
authors.initials: V
authors.lastname: Tung