Laser direct writing using nanomaterials and device applications towards IoT technology

Akira Watanabe, Jinguang Cai, Sayaka Ogawa, Eiji Aoyagi, Shun Ito

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


The electronic interconnection based on solution processes using nanomaterials is one of the key technologies in the printed electronics towards flexible and wearable devices in IoT. The laser direct writing of three kinds of conductive micropatterns and the device applications were studied. The first one is a Cu micro-grid structure using a Cu nanoparticle ink and the application to a strain sensor. The second one is a reduced graphene oxide (rGO) interdigitated electrode prepared by laser-induced reduction of graphene oxide (GO) and the application of an rGO/GO/rGO interdigitated microelectrode to a humidity sensor. The third one is a carbon interdigitated electrode prepared by laser carbonization of a polyimide (PI) film and the application to an in-plane micro-supercapacitor (MSC). One of the important features in wearable devices is the stability and reliability under bending conditions. The influences of bending in the electric properties were studied for the Cu micro-grid and an rGO/GO/rGO interdigitated electrode. Remarkable resistance change of the Cu micro-grid structure was observed in bending experiment. An unusual large resistance change was explained by a nanostructure remaining even after sintering. On the other hand, the rGO/GO/rGO structure showed excellent stability of the output signal in humidity sensing experiments against bending. Such a stable electronic properties against bending stress was attributed to the electronic conductivity based on π-π interaction between graphene planes. A crystalline layered structure of graphene planes were clearly observed in TEM images for an rGO film.

Original languageEnglish
Title of host publicationAdvanced Laser Processing and Manufacturing II
EditorsMinghui Hong, Rongshi Xiao, Jian Liu
ISBN (Electronic)9781510622241
Publication statusPublished - 2018 Jan 1
EventAdvanced Laser Processing and Manufacturing II 2018 - Beijing, China
Duration: 2018 Oct 112018 Oct 13

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherAdvanced Laser Processing and Manufacturing II 2018


  • IoT
  • flexible electronics
  • graphene oxide
  • humidity sensor
  • in-plane micro-supercapacitor
  • laser direct writing
  • metal nanoparticle ink
  • nanomaterial
  • reduced graphene oxide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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