Laser-induced S-doped carbon on flexible polycarbonate substrate for electromagnetic interference shielding

Abstract

Biomass-derived carbon structures are attractive candidates for developing electromagnetic (EM)-wave-shielding materials because of their stability and unique porous structures. Lignin is the second-most abundant biomass that can be converted to porous carbon structures by using different methods. Herein, laser writing/patterning was employed to prepare lignin-derived S-doped carbon on a flexible polycarbonate substrate (C/PC) for EM wave shielding. An ultrathin carbon area (thickness of ∼ 20 µm) was formed on the flexible PC after laser processing, and its average surface resistance was 50.5 Ω. The performance of the prepared C/PC as an EM-wave-shielding material was examined in the X-band. Most of the incident EM waves can be reflected through S-doped carbon surface and remaining waves can be absorbed. The total shielding effectiveness (SE_T) attained 32.7 dB at 9.6 GHz when three layers of carbon were used as the shielding material; the absorption effectiveness (SE_A) values were higher than the reflection effectiveness (SE_R) values throughout the X-band. This result indicated that the presence of porous conductive carbon skeletons can effectively provide surface reflections and facilitate multiple reflections and scattering of the incident EM waves Our investigation provides a rapid and easy synthesis method for designing EM-wave-shielding materials based on lignin-derived porous carbon.