High-temperature, thin, flexible and transparent Ni-based heaters patterned by laser-induced reductive sintering on colorless polyimide

This study reports a novel method for the fabrication of a high-performance, flexible and transparent heater (TH) comprising imperceptible nickel (Ni) micropatterns on a colorless polyimide (cPI) substrate. The specially developed laser digital patterning (LDP) process, which utilizes laser-thermal degradation of organic surfactants generating reducing agent, enables a fast, affordable, and reliable way to form Ni-grid/cPI structures with a low sheet resistance (26.3 Ω sq⁻¹) and a high transmittance (87.3% at 550 nm). Thanks to the thermal stability of Ni and cPI, together with the low sheet resistance, the Ni/cPI TH exhibits stable performance even at the highest heating temperature ever reported for flexible TH (310 °C at 11 V). As a consequence, the proposed scheme realizes an advanced process for the fabrication of chemically and mechanically stable, lightweight (4.1 mg cm⁻¹), high-performance, and flexible TH.