Highly transparent multilayer organic thin film for effective antistatic and electromagnetic interference shielding applications

Graphene-based materials have garnered tremendous interest as electromagnetic interference shields for various applications in healthcare, wireless communications and positioning systems, and space microelectronics. This is because they can circumvent the common drawbacks of metal-based shields, including weight and corrosion. In the present work, we report a ~30-nm highly transparent shield with 93% optical transmission that can attenuate the incident electromagnetic waves by ~94% in the X-band frequency range, offering an electromagnetic interference (EMI) shielding effectiveness of 13.3 dB at 8.2 GHz. The shield is designed in a layer-by-layer assembly, featuring two layers of the conductive sulfuric acid post-treated poly(3,4-ethylenedioxythiophene)poly(styrene sulfonate) (PEDOT:PSS) polymer sandwiching reduced graphene oxide (rGO) nanosheets in between. The assembled shield possesses a shielding to thickness figure-of-merit ratio of 400 dB µm –1 , which is far superior to the reported values for graphene-based metal-free transparent shields. The multilayer rGO/PEDOT:PSS ultrathin film can be easily fabricated by a simple, cost-effective approach for various electrostatic discharge and EMI shielding applications. Impact statement Our work is the first study to introduce the viability of a highly transparent antistatic and electromagnetic interference (EMI) shield using reduced graphene oxide (rGO) as an interlayer within two nanolayers of poly(3,4-ethylenedioxythiophene)poly(styrene sulfonate)—an intrinsically conducting polymer also known as PEDOT:PSS. The developed 30-nm sandwich assembly resulted in an ultrathin film with high optical transparency of 93% that could attenuate 93.5% of the incident electromagnetic waves. The fabricated thin shield demonstrates a total EMI shielding effectiveness of 13.3 dB at 8.2 GHz in the X-band frequency range. This specific assembly design of rGO and PEDOT:PSS presented a thickness-specific shielding effectiveness of 400 dB µm –1 , which is a record figure of merit compared with the reported values for previously “transparent” shields among “metal-free graphene-based” composites to date. To the best of our knowledge, no prior study has been reported on the “transparent” ESD/EMI shields based on the solution-processing of PEDOT:PSS and rGO. Graphical abstract