Carbon Fiber Reinforced Polymer (CFRP) coated with 2D TMDs - WSe₂, and topological insulator, Bi₂Se₃, films for EMI shielding applications.

Electromagnetic interference (EMI) pollution is significantly caused by the high density of electronic equipment in our proximity due to the ever-growing IT industry. Remediation of EMI pollution can be in the form of engineered shielding materials. TMDs show layer-dependent shielding efficiency (SE) at microwave frequencies. At the same time, carbon composites are excellent EMI shielding materials, so we designed heterostructures of TMD and CFRP to get the combined efficiency. TMD materials - WSe2, a p-type semiconductor, and Bi2Se3 - a topological insulator (TI) are used used for coating on the CFRP. Thin films of WSe2 and Bi2Se3 (thickness 1ML and 10ML) were deposited on CFRP by pulsed DC and RF sputtering, respectively. The films transport properties were characterized by PPMS and structural properties by TEM, SAED, EDS, RAMAN and XPS. The shielding efficiency (SE) is measured using the free space-focused beam method for 18- 40 GHz. The SE of specimens varies from ~-60 dB to ~-4.0 dB, as applied electric field direction changes from transverse to orthogonal w.r.t the directions of the fibers. The increased SE of CFRPs coated with 2D TMDs, involves both reflection and absorption mechanisms, and result in a multifunctional electromagnetic material. The films were further pattern-coated with carbon nanotubes (CNT) to study the effect of CNT deposited in different shapes to increase the SE of the samples prepared.