LAUSR

Transparent electromagnetic interference (EMI) shields are increasingly in demand for medical, military, wireless net-works, aerospace electronics and navigation control systems. To date, studies have mixed pristine and/or doped con-ductive polymers with carbon allotropes and metallic fillers to increase the total shielding effectiveness, compromising the transparency, amount of the material used and weight of the shields. Obtaining cost-effective and transparent EMI shields without the need to incorporate fillers is extremely desirable. Herein, we implement a design strategy for fabri-cating a gigahertz (GHz) highly transparent shield made of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). A total EMI shielding effectiveness of 15 dB is achieved in the X-band frequency range for a 50 nm ultra-thin film with a high transparency of 97.1%. The fabricated filler-free EMI shield holds a record thickness-specific shield-ing figure-of-merit of 300 dB/µm - far exceeding the best values for micron-thick silver-based, as well as carbon- and MXene-based composite materials shields - with even a higher transparency. The feasibility of the developed filler-free shield for large-scale applications is validated by its integration into a cell phone display glass, as a prototype, in which the EMI shielding effectiveness elevates to 18.3 dB.