INVESTIGATION OF LASER SCRIBING MECHANISMS FOR METALLIC THIN FILMS ON A FLEXIBLE SUBSTRATE TOWARDS PHOTOVOLTAIC SOLAR MODULE MANUFACTURING

Laser scribing of thin films has proven to be an efficient device fabrication route on temperature sensitive substrates leveraging precisely localized heating capabilities. However, the quality of laser scribing is often unsatisfactory mainly due to lack of understanding on complex thermo-mechanical mechanisms induced by short and ultrashort pulsed lasers. This study focused on reviewing our recent achievements related to unveiling mechanisms of laser scribing of bi-layered molybdenum thin films on flexible polyimide substrate towards thin film photovoltaic module manufacturing. We experimentally compare the performance of pico-and nanosecond laser-based scribing in conjunction with morphological analysis and electrical shunt evaluation. Thermal analysis to understand spatiotemporal temperature evolution, and time-resolved measurement of laser-induced emission will further elucidate relevant scribing mechanisms. It will be shown that tuning of laser pulse duration depending on thickness and properties of thin films can preferentially launch indirect interfacial heating mechanism, enabling shunt-free optoelectronic device fabrication.