NUS Enterprise

Solution-Processable Functionalised Graphene Nanosheets

Technology #ho-p-04

Solution-Processible Graphene For Plastic Electronics

Prof. Peter Ho, Prof Chua Lay-Lay, Dr. Wang Shuai, Dr. Chia Perq-Jon,

Dr. Goh Ghim Siong  

Department of Physics

Industry Problem

Graphene is attractive for a wide range of applications such as high frequency transistors, flexible electronics and supercapacitor electrodes. However, graphene fabrication by chemical vapor deposition on catalytic metal substrates requires temperatures above 1000oC and an additional transfer step to deposit graphene on the target substrate. Graphene fabrication by graphite exfoliation results in partially exfoliated structures of thick aggregated stacks of graphene sheets. Hence, there is a need for solution dispersible graphene sheets that can be readily deposited onto target substrates at relatively low temperatures (>150oC), for organic electronic applications. 

Solution

Prof. Peter Ho’s group from the Department of Physics has developed oxygen-containing graphene nanosheets which are: (i) surface-grafted with organic-soluble or water-soluble components; (ii) form stable dispersions at high concentrations in the appropriate organic or water-based solvents, and (iii) the ratio of oxygen atoms bonded to the graphene oxide nanosheet to the carbon atoms in the graphene nanosheet is sub-stoichiometric (that is O:C is less than 1:2). This material is dispersible in high concentration (>15 mg mL-1) in appropriate solvents without aggregating/precipitating over extended periods at room temperature. The excellent dispersability of the surface grafted oxygen containing graphene nanosheets at the single sheet level in organic solvents is sufficient for spin coating and printing onto a variety of substrates. The films may then be readily deoxidized to graphene (eg. about 80% completion at 300oC, or by chemical reduction) to give, for example, a network of low dimensional graphenite tracks and dots on the nanosheets. NUS has applied for patent protection for the invention.

Fig. 1: X-ray diffraction of graphite oxide.

Fig. 2: Spin-coated layer nanosheet of surface-grafted oxygen-containing graphene.

Fig. 3: Field-effect transistor with a layer of graphene.

Value Proposition

  • Direct deposition of graphene nanosheet films on a variety of substrates possible, without the need of transfer process.
  • Graphene films are fabricated at low temperatures (<300oC), easy integration for plastic electronics.
  • Graphene nanosheet films are customisable to be soluble in organic solvents or water.

Potential Applications

  • Electrodes for supercapacitors, batteries and devices
  • Semiconductors in field-effect transistors
  • Heat conductive coating

 For more information contact: NUS Industry Liason Office

+65 6516 7175/+65 6601 2812

iloquery@nus.edu.sg/tan.yan.ny@nus.edu.sg

Case Manager: Dr. Tan Yan Ny

Ref : HO-P04

Principal Investigator: Prof Peter Ho