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

Abstract

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.

Facile Green Synthesis of BCN Nanosheets as High‐Performance Electrode Material for Electrochemical Energy Storage

“…For comparison, Raman spectra of the BN adduct and h‐BN are shown in Figure S1 of the Supporting Information. In the case of the BN adduct no peak was detected, but in the case of h‐BN one distinct peak appeared at 1371 cm −1 (Supporting Information, Figure S1) …”

“…In the case of the BN adduct no peak was detected, but in the case of h-BN one distinct peak appeared at 1371 cm À1 (Supporting Information, Figure S1). [19,30,31] Figure 1C shows superimposed FTIR spectra of BCN NSs and glucose-derived carbon to revealt he common features. For example,t he peak at 785 cm À1 is due to the presence of BÀN bondsi nB CN,a nd the broad peak between 1100 and 1250 cm À1 is due to the C=Ns tretching vibration.…”

Modulating the electronic and magnetic properties of graphene

“…Among the elements of group IIIA, extensive studies have been conducted on substitutional doping of boron in graphene due to its similar atomic size to the C atoms of graphene. Different techniques, such as the arc discharge method, 152 CVD, 153,154 hydro and solvothermal treatments, 155,156 Wurtz-type reductive coupling 157 and post functionalization 158 with different graphene and boron sources have been adopted by many groups for the synthesis of boron-substituted graphene (B-G). The substituted B atom does not change the hexagonal sp 2 planar characteristics of graphene.…”

Ultrathin flexible graphene films with high thermal conductivity and excellent EMI shielding performance using large-sized graphene oxide flakes

“…For the portion of waves able to enter shielding materials, absorption loss is the dominant consumption of this EM energy, which depends on the interaction between conducting parts of shielding materials and EM waves. 7,9,10 Hence, materials with high electrical conductivity, such as metals, carbon materials and conductive polymers, have been applied as effective EMI shielding materials. However, metal shielding materials have the disadvantages of high densities and easy corrosion, limiting their application in lightweight, wearable electronic equipment.…”