Charge transport mechanism of thermally reduced graphene oxide and their fabrication for high performance shield against electromagnetic pollution

• Graphene oxide has been synthesized by Improved Hummer’s Method.
• Graphene oxide was reduced at different temperatures.
• The graphene sheets get segregated and dc conductivity increases with reduction.
• The maximum EMI shielding efficiency of 80.81 dB is obtained in highly reduced sample.
• Variable range hopping model is used to explain charge conduction in the samples.

Shielding devices from thermally reduced graphene oxide have been fabricated for superior electromagnetic interference (EMI) shielding effectiveness. The prepared pristine samples of graphene oxide were reduced at different temperatures. The samples of the thermally reduced graphene oxide were tested in the frequency range of 12.4–18 GHz (Ku band) and the maximum value of EMI shielding efficiency was found to be 80.81 dB for the sample reduced at 1073 K. The charge transport mechanism of thermally reduced graphene oxide samples was also investigated in the temperature range of 10–300 K. The increase in electromagnetic shielding efficiency of thermally reduced graphene oxide samples is attributed to increase in the conductivity and the number of graphitic domains in it. The increase in number of graphitic domains is quantitatively explained on the basis of Tuinstra and Koenig relation. The results show great potential of thermally reduced graphene oxide as a new type of microwave absorbing material.

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