Ambient-Spray Ni–Cu(–O)/Ag Nanowire Transparent Heaters for High-Temperature Heating and Far-/Near-Field EMI Suppression

Abstract

Modern optoelectronics demand highly efficient transparent heaters that concurrently suppress electromagnetic interference (EMI). To address this, we present a fully solution-processed, vacuum-free Ni–Cu(–O)/Ag nanowire platform stabilized by a silica-hybrid overcoat. The conformal Ni–Cu(–O) shell bridges interwire junctions, transforming fragile point contacts into robust pathways. This architectural breakthrough dramatically enhances Joule heating efficiency and thermal stability. At ∼75% transmittance, the ultrathin (55.6 nm) films deliver an exceptional heating performance up to 438°C (458°C·cm²·V⁻¹) without defect-driven failure, alongside extreme mechanical durability (ΔR/R₀ < 1% over ∼7000 bending cycles). Crucially, this high-performance heating platform also provides highly tunable EMI shielding. By tuning the Ni/Cu ratio, we effectively modulate the relative contributions of reflection and absorption loss. While high reflection governs far-field shielding (total effectiveness ≥ 32 dB), adequate non-reflective absorption is essential to dissipate trapped electromagnetic energy and prevent secondary internal reflections in integrated devices. Supported by direct near-field magnetic scanning, our tailored core–shell architecture introduces a vital dissipative channel that actively suppresses this local magnetic noise, ensuring supreme electrothermal heating while enabling optimal, on-demand EMI protection.