Controllable Fabrication of Transparent Macroporous Graphene Thin Films and Versatile Applications as a Conducting Platform

Abstract

4334 wileyonlinelibrary.com strength, [ 2 ] and prominent optical and electrochemical properties. [ 3 ] However, the macroscopic properties of graphene materials are determined by the assembled structures of graphene sheets. So far, various types of graphene-assembled structures have been developed, including graphene fi bers, [ 4 ] 2D compact constructs including graphene papers and fi lms, [ 5 ] and 3D porous graphene scaffolds such as monoliths [ 6 ] and beads. [ 7 ] 2D compact graphene thin fi lms (CGTFs) can be prepared by chemical vapor deposition (CVD), [ 8 ] vacuum fi ltration, [ 5a,b ] Langmuir-Blodgett method, [ 5c ] spin coating, [ 9 ] and layer-by-layer assembly, [ 10 ] and they have been demonstrated potential applications in photo response and chemical/biological sensors, [ 10,11 ] as well as transparent electrodes for fl exible electronic and optoelectronic devices. [ 5b , 12 ] 3D porous graph ene structures can be prepared by hard template-assisted CVD, [ 6a ] hydrothermal approach, [ 13 ] freeze-drying method, [ 6b ] and functional polymer-assisted assembly. [ 7,14 ] And such 3D graphene structures have been widely used in electromagnetic interference shielding, catalyst carriers, and energy storage and conversion. [13][14][15] As a new assembly structure of graphene, transparent macroporous graphene thin fi lms (MGTFs) that combine the features of the 2D graphene fi lms (being micrometers thick and transparent) and the 3D porous monoliths (having macroporous structure and large specifi c surface area) are destined to be promising as porous electrode materials for applications such as optoelectronics, photo/photoelectrochemical catalysis, energy storage/conversion devices, and chemical/biological sensing, where the specifi c surface area and/or the transparency play important roles in determining the performance of electrodes. [ 16 ] However, preparation of such transparent MGTFs is challengeable due to both scientifi c and technical limitations: the π-π stacking and van der Waals force interactions between the basal planes of graphene sheets result in irreversible aggregation and restacking of the graphene sheets during processing. Recently, strategies, including nucleate boiling, [ 17 ] breath fi gure, [ 18 ] and electrochemical deposition of graphene oxide (GO), [ 15e ] were proposed to assemble graphene sheets into macroporous thin fi lms. However, the walls in the macroporous structures prepared by these methods were thick due to the restacking of GO Controllable Fabrication of Transparent Macroporous Graphene Thin Films and Versatile Applications as a Conducting PlatformJinhua Sun , Mushtaque A. Memon , Wei Bai , Linhong Xiao , Bin Zhang , Yongdong Jin , Yong Huang , and Jianxin Geng * Graphene sheets have been demonstrated to be the building blocks for various assembly structures, which eventually determine the macroscopic properties of graphene materials. As a new assembly structure, transparent macroporous graphene thin fi lms (MGTFs) are not readily prepared due to the...

Real-time imaging of Na + reversible intercalation in “Janus” graphene stacks for battery applications

“…S1 and S4D). The change in chemical functionalization was evident also from water contact angle measurements ( 22 ); the AB and NB functional groups are more hydrophilic than pristine CVD graphene; thus, water contact angle decreased from ca. 83° to ca.…”

Encoding Enantiomeric Molecular Chiralities on Graphene Basal Planes

“…As illustrated in Figure 2a, the molecular imprints introduced on the graphene basal plane would either adsorb or block a Trp enantiomer from approaching the electrode depending on their geometries (i.e., their chirality). The peaks observed in the DPV curves are due to the oxidation of Trp ( S6a) [13] [14] This was verified by repeating the experiments with compact D-Trp-rG-O and L-Trp-rG-O films as electrodes, where no enantioselective detection was observed (Figure S7). It is noted here that the chirality-encoded electrodes prepared from CVD graphene showed noticeable enantioselective responses (Figure 2b-e).…”

Calcium Carbonate@silica Composite with Superhydrophobic Properties

“…The hydrophobic performance was obtained by measuring the contact angle of water droplets on the surface of the materials [ 66 , 67 ]. The contact angles of the cubic calcium carbonate, spherical calcium carbonate and composite material are shown in Figure 9 .…”