Laser nanowire films promise EMI shielding for 6G devices

A new nanofabrication method developed at the University of Glasgow could influence how next-generation electronic devices are designed to cope with electromagnetic interference (EMI), especially for upcoming technologies such as 6G wireless communication networks, Wi-Fi systems, radar, and biotelemetry.

Published in the December 2025 issue of ACS Nano, the research outlines a dual-process innovation combining interfacial dielectrophoresis (i-DEP) with non-contact picosecond laser processing to fabricate ultrathin, transparent, and flexible EMI shielding films using aligned silver nanowire (AgNW) networks.

The method provides a solution to a longstanding material challenge—achieving high shielding effectiveness without compromising optical transparency or requiring complex manufacturing steps.

Scalable EMI Shielding for Next-Gen Wireless Devices

As wireless spectrum becomes more crowded and transmission power increases across consumer, industrial, and healthcare domains, EMI shielding has become critical to ensure signal integrity and device safety. Traditional shielding materials, such as metal foils, are rigid, opaque, and unsuitable for modern flexible electronics.

The University of Glasgow’s James Watt School of Engineering team, led by researchers at its Microelectronics Laboratory (meLAB), addressed this gap by designing a method that allows nanowires—each a thousand times thinner than a human hair—to be arranged in precise geometries onto thin polyimide (PI) substrates, using electric fields to guide their positioning.

This first step, the i-DEP, uses a non-uniform AC electric field to orient nanowires both translationally and rotationally across predefined patterns. The research demonstrated programmable assemblies spelling out “NANO” and “UOG” to validate directional control.

In the second step, ultrafast picosecond laser pulses were applied to the aligned nanowire films. This laser post-treatment fused junctions between wires and removed residual polyvinylpyrrolidone (PVP) insulating layers, thereby enhancing both electrical conductivity and optical transmittance. Notably, the films achieved a 46× reduction in sheet resistance and a 10% increase in transparency, reaching 83.1% at 550 nm.

The tests showed that the films provide over 35 dB shielding effectiveness across the 2.2 to 6 GHz frequency band. This range includes signals used by Wi-Fi 6/7, mid-band 5G, radar systems, and emerging 6G applications, making the films highly relevant for future-proofing telecom equipment.

Overcoming the Conductivity-Transparency Trade-Offs

“This is the first time anyone has overcome the longstanding trade-off between electrical conductivity and optical transparency in metallic nanowire networks,” said Jungang Zhang, lead author of the study. “After our laser post-treatment, both the conductivity and transparency improve simultaneously”.

A core innovation lies in the creation of a capacitively coupled interwire network. The aligned structure leaves nanogaps between wires, forming microscopic capacitors that enhance local electric-field coupling and displacement current. This mechanism contributes significantly to EMI shielding—well beyond the role of conductivity alone.

Compared to randomly oriented drop-cast networks, the aligned and laser-treated films deliver a 1000× improvement in shielding effectiveness. The total film thickness is just 5.1 microns, allowing the films to bend, wrap, and conform to surfaces without loss of performance, making them suitable for wearables, foldable displays, transparent antennas, and implantable medical devices.

Use Cases: From Wireless Healthcare to Smart Infrastructure

The transparent and flexible EMI shielding material could play a key role in several high-growth telecom-related domains.

• 6G and Wi-Fi 7 base stations: With higher frequencies and antenna densities, these systems face more cross-talk and need passive EMI suppression at the component level.
• Transparent user interfaces: In smart glasses, head-up displays, or foldable phones, display-integrated antennas and sensors require shielding layers that do not block light or interfere with form factor.
• Wearables and implantables: Devices for remote patient monitoring, such as ECG patches or neural sensors, often suffer from interference caused by nearby smartphones or Wi-Fi routers. These films could serve as bio-compatible shielding enclosures.
• Radar and edge computing: In automotive or industrial IoT applications, especially those using radar or mmWave communication, the films can prevent performance degradation due to environmental EM noise.

In real-world testing, the researchers demonstrated the material's effectiveness by blocking a 5 GHz Wi-Fi signal in an anechoic chamber. A mobile phone acting as a hotspot saw a 15 dB drop in signal strength when shielded by the AgNW film, indicating a 30-fold reduction in signal power at that frequency.

Enabling Telecom Hardware Innovation Without a Cleanroom

Beyond the material performance, the fabrication approach offers advantages in cost and scalability. The maskless, cleanroom-free laser ablation process enables fast production of customised electrode geometries for large-area nanowire assemblies. The researchers demonstrated prototypes measuring up to 80 cm², with the potential to scale further using roll-to-roll techniques.

“The EMI shielding performance of the materials we created improves on the performance of non-aligned nanowires by more than a thousand times,” said Professor Hadi Heidari, corresponding author and head of meLAB.

The research was funded by the UK’s Engineering and Physical Sciences Research Council (EPSRC), and the team plans to explore integration with multilayered and conductive top-coating systems to further enhance shielding performance in complex electromagnetic environments.