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Microwave-Assisted Synthesis of Boron and Nitrogen co-doped Reduced Graphene Oxide for the Protection of Electromagnetic Radiation in Ku-Band

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journal contribution
posted on 2015-09-09, 00:00 authored by Sima Umrao, Tejendra K. Gupta, Shiv Kumar, Vijay K. Singh, Manish K. Sultania, Jung Hwan Jung, Il-Kwon Oh, Anchal Srivastava
The electromagnetic interference (EMI) shielding of reduced graphene oxide (MRG), B-doped MRG (B-MRG), N-doped MRG (N-MRG), and B–N co-doped MRG (B–N-MRG) have been studied in the Ku-band frequency range (12.8–18 GHz). We have developed a green, fast, and cost-effective microwave assisted route for synthesis of doped MRG. B–N-MRG shows high electrical conductivity in comparison to MRG, B-MRG and N-MRG, which results better electromagnetic interference (EMI) shielding ability. The co-doping of B and N significantly enhances the electrical conductivity of MRG from 21.4 to 124.4 Sm–1 because N introduces electrons and B provides holes in the system and may form a nanojunction inside the material. Their temperature-dependent electrical conductivity follows 2D-variable range hopping (2D-VRH) and Efros–Shklovskii-VRH (ES-VRH) conduction model in a low temperature range (T < 50 K). The spatial configuration of MRG after doping of B and N enhances the space charge polarization, natural resonance, dielectric polarization, and trapping of EM waves by internal reflection leading to a high EMI shielding of −42 dB (∼99.99% attenuation) compared to undoped MRG (−28 dB) at a critical thickness of 1.2 mm. Results suggest that the B–N-MRG has great potential as a candidate for a new type of EMI shielding material useful in aircraft, defense industries, communication systems, and stealth technology.