High‐speed direct laser writing of silver nanostructures via two‐photon reduction

Despite the widespread use of metallic nanostructures in several emerging applications, high-throughput template-free fabrication techniques that are capable of patterning arbitrarily complex nanostructures are lacking. Two-photon reduction-based direct laser writing is a promising technique due to its ability to fabricate geometrically intricate metallic structures with sub-diffraction nanoscale features. Unfortunately, the extremely low writing speed of approximate to 10 mu m s(-1) makes this process impractical for large-scale manufacturing. The operating speed is currently limited by a lack of photoresist materials that can operate under high-speed writing conditions. Herein, a silver-containing aqueous photoresist recipe is presented that increases the writing speed to 1 cm s(-1) while maintaining the ability to fabricate sub-diffraction silver nanowires as thin as 500 nm. In addition, the electrical conductivity of the printed silver is within one-fifth that of bulk silver. Strikingly, it is demonstrated here that the conventional design rule of using surfactants to promote high-quality printing is faulty under high-speed conditions. Instead, surfactants limit the throughput and are eliminated to enable high-speed writing. The 1000x throughput scale-up presented here significantly improves our ability to transition nano-enabled devices from research laboratories to real-world adoption.