Ultra-broadband nickel-polyimide metasurface bridging solar absorption, thermal emission and TPV conversion

Abstract Most reported metasurface absorbers optimize a single function e.g., absorption, emission or solar-to-electrical conversion and often lose performance at oblique angles. We introduce a nickel-polyimide-nickel architecture that unifies all three. A patterned nickel resonator over a polyimide spacer and nickel backplane creates overlapping resonances and strong cavity confinement yielding over 90% absorption from 153.60 to 1882.2 THz (1952 to 159.3 nm) with an average of 96.05% and above 80% from 105 THz to beyond 2500 THz (2855 nm to below 120 nm). Under AM 1.5 illumination, solar absorption efficiency reaches 97.06%. As a thermal emitter, the device attains 94.68% efficiency at 3500 K and its solar-to-electrical conversion peaks at 66% at 1000 K. The design is polarization-insensitive and sustains above 80% absorption up to 50°, positioning it for practical solar-thermal and thermophotovoltaic deployment.