title: Transparent and flexible cellulose nanocrystal/reduced graphene oxide film for proximity sensing.
abstract: The rapid development of touch screens as well as photoelectric sensors has stimulated the fabrication of reliable, convenient, and human-friendly devices. Other than sensors that detect physical touch or are based on pressure sensing, proximity sensors offer controlled sensibility without physical contact. In this work we present a transparent and eco-friendly sensor made through layer-by-layer spraying of modified graphene oxide filled cellulose nanocrystals on lithographic patterns of interdigitated electrodes on polymer substrates, which help to realize the precise location of approaching objects. Stable and reproducible signals generated by keeping the finger in close proximity to the sensor can be controlled by humidity, temperature, and the distance and number of sprayed layers. The chemical modification and reduction of the graphene oxide/cellulose crystal composite and its excellent nanostructure enable the development of proximity sensors with faster response and higher sensitivity, the integration of which resolves nearly all of the technological issues imposed on optoelectronic sensing devices.
authors.affiliation: Center for EAPap Actuator, Dept. of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Ku, Incheon, 402-751, South Korea.
authors.forename: Kishor Kumar
authors.initials: KK
authors.lastname: Sadasivuni
authors.forename: Abdullahil
authors.initials: A
authors.lastname: Kafy
authors.forename: Lindong
authors.initials: L
authors.lastname: Zhai
authors.forename: Hyun-U
authors.initials: HU
authors.lastname: Ko
authors.forename: Seongcheol
authors.initials: S
authors.lastname: Mun
authors.forename: Jaehwan
authors.initials: J
authors.lastname: Kim
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D004563:Electrochemistry; D004566:Electrodes; D004581:Electronics; D004867:Equipment Design; D003368:Gossypium; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D006860:Hydrogen Bonding; D017953:Isocyanates / Q000737:chemistry; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation; D055095:Optics and Photonics; D010087:Oxides / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D017953:Isocyanates; D010087:Oxides; D006108:Graphite; D002482:Cellulose
keywords: cellulose; graphene oxide; nanocrystals; optoelectronics; sensors