Remanufacturing transparent conductive oxide electrodes using ultrafast on-demand laser fabrication

As a new approach to achieving a circular economy, we propose "in-process" remanufacturing, in which a remanufacturing loop is built within the manufacturing process, and products with defects are returned to the production line as new. Many defects occur in the production line of transparent oxide electrodes that are used in displays and heaters, making them good candidates for in-process remanufacturing. Achieving this goal requires a process that can produce ceramic films on-demand at an ultrahigh speed. Photo-assisted chemical solution deposition is a ceramic coating technique that combines a solution method and photoirradiation; however, the process elements include a heating step, which causes process fragmentation. Herein, we successfully formed ceramic films on-site at high speed by seamlessly connecting all processes after microdeposition using all-optical methods. As a demonstration, first, tin-doped indium oxide (ITO) ink obtained via wet-ball milling was deposited on the defective area of the simulated electrode. Conduction was successfully restored by irradiating the deposited precursor film using a 24 W cm-2 UV-LED source for 60 s, followed by Nd:YAG laser (266 nm) irradiation from 0 mJ cm-2 to a final fluence (FF) of 12 mJ cm-2 over 100 s. The introduction of a pulse for slope (PS), which gradually increases the laser intensity, enhanced the decomposition of metal-organic compounds in the ITO ink during laser irradiation without film destruction, forming a solid electrical conduction path and inducing crystal growth. Consequently, the electrical resistivity was successfully reduced to 6.9 m omega cm via light irradiation for only 160 s under an FF and a PS of 12 mJ cm-2 and 1000, respectively. This ultrafast ceramic film formation method is expected to lead to new manufacturing processes. On-demand high-speed laser repair of ceramic thin films presents a new concept of in-process remanufacturing for a circular economy.