Uniformly connected conductive networks on cellulose nanofiber paper for transparent paper electronics

Abstract

We demonstrate the fabrication of highly transparent conductive networks on a cellulose nanofiber paper, called cellulose nanopaper. Uniform coating of the conductive nanomaterials, such as silver nanowires (AgNWs) and carbon nanotubes, is achieved by simple filtration of their aqueous dispersions through the cellulose nanopaper, which acts as both filter and transparent flexible substrate. The as-prepared AgNW networks on the nanopaper offer sheet resistance of 12 X sq. À1 with optical transparency of 88%, which is up to 75 times lower than the sheet resistance on a polyethylene terephthalate film prepared by conventional coating processes. These results indicate that the 'filtration coating' provides uniformly connected conductive networks because of drainage in the perpendicular direction through paper-specific nanopores, whereas conventional coating processes inevitably cause self-aggregation and uneven distribution of the conductive nanomaterials because of the hard-to-control drying process, as indicated by the well-known coffee-ring effect. Furthermore, the conductive networks are embedded in the surface layer of the nanopaper, showing strong adhesion to the nanopaper substrate and providing foldability with negligible changes in electrical conductivity. This filtration process is thus expected to offer an effective coating approach for various conductive materials, and the resulting transparent conductive nanopaper is a promising material for future paper electronics.

Water-Resistant, Transparent Hybrid Nanopaper by Physical Cross-Linking with Chitosan

“…1 , 2 It allows strong films, leading to several potential applications including structural materials and gas barriers in packaging, templates for functional materials, and substrates for transparent electronics and devices. 3,4,5,6,7,8,9,10,11 The strength of the junctions between the nanofibers forming the disordered networks is central to transfer the high mechanical properties of the individual nanofibers up to the macroscopic material. Such interactions can be subtle, involving hydrogen bonding and other interactions.…”

All-nanocellulose nonvolatile resistive memory

“…[10][11][12][13][14][15][16] Therefore, nanopaper has recently received much attention as a substrate for flexible electronics. 9,[17][18][19][20][21][22][23][24][25][26][27][28][29] To date, various electronic devices including organic/inorganic thin-film transistors, 9,21-23 light-emitting diodes, 24 solar cells, 23,25,26 antennas 27,28 and triboelectric generators 29 have been demonstrated on nanopaper substrates. However, a nonvolatile memory, which is the essential component for IoE technology, has not been demonstrated on a nanopaper substrate so far.…”

Clear transparent cellulose nanopaper prepared from a concentrated dispersion by high-humidity drying

“…In the current process, starting from a low concentration dispersion of less than 0.5 wt%, clear transparent nanopaper can be fabricated by ltration 1,8,16,17 or castdrying, 2,10,17 both of which are highly energy-and timeconsuming because of the high water load (99.5 wt%) in the cellulose nanober dispersion (0.5 wt% cellulose nanober). In this context, therefore, the fabrication of clear transparent nanopaper should start from a high concentration dispersion, which will reduce energy and time consumption, leading to the realization of exible devices based on nanopaper.…”