High‐Efficiency and Low‐Intensity Threshold Femtosecond Laser Direct Writing of Precise Metallic Micropatterns on Transparent Substrate

Abstract Laser direct writing (LDW) is a promising approach for fabricating metallic micropatterns on transparent substrates for transparent electronic circuits that satisfy both electronic and optical criteria. However, high efficiency and precision patterning remain a challenge for both photochemical and photothermal LDW. Herein, a novel method is proposed with a femtosecond laser to achieve a highly‐efficient photothermal process via single‐photon absorption by photosensitive particles (SPA‐FsLDW). The dispersive photosensitive particles act as numerous heating sources, enabling simultaneous multiple‐location photothermal reactions and highly‐efficient metallization due to heat‐induced metal ion reduction. The new approach effectively exploits the excellent heat‐input regulation with the ultrashort pulse of the femtosecond laser to achieve great temperature controllability and precision. It is shown that, with a deposition rate of ≈10 7 µm 3 s −1 and electrical resistivity of ≈10 −7 Ω m, SPA‐FsLDW improves efficiency and electrical resistivity by at least one order of magnitude compared to previously reported FsLDW. A self‐powered sensor is fabricated using SPA‐FsLDW, demonstrating its practical applicability.