Future Laser Manufacturing of Nanostructured Metal Oxide Semiconductors for Functional Materials and Devices

Nanostructured metal oxide semiconductors play a critical role in enabling the development of new platforms for a wide range of applications, including energy conversion (solar cells, nanogenerators, fuel cells), energy storage (batteries, supercapacitors), optoelectronics (photo-detectors, light-emitting diodes (LEDs), laser diodes), sensors, transistors and catalysts. However, the manufacturing of nanostructured semiconductors faces a significant challenge to achieve combined large-scale, low-temperature, cost-effective, high productivity, size-controlled materials and devices with ease of fabrication. We aim to provide a solution to these challenges through developing a scalable, rapid, low-temperature laser manufacturing technology that is applicable to a wide range of nanostructured semiconductors. Three types of nanostructured metal oxide semiconductors (SnO2, TiO2 and ZnO) will be synthesised via a one-step, rapid and low-temperature laser-assisted hydrothermal technique (LAHT) in ambient air on both rigid and flexible substrates up to 32 cm2 (2.5" wafer size), within 1 - 2 mins. This will be achieved using a tailored, expanded beam configuration of a high-power fibre laser without beam scanning, which enables the LAHT process to be efficiently incorporated into roll-to-roll manufacturing processes without the use of autoclaves and furnaces. To be able to control the growth of nanostructured metal oxides in terms of morphology, crystallinity and orientation, the project offers an opportunity to explore underlying mechanisms of large scale growth of various nanostructured metal oxides via LAHT, and to establish understanding the performance of the functional devices, i.e. power conversion efficiency and operational stability, sensitivity and durability through the assembly of perovskite solar cells and ultraviolet photodetectors. This will directly advance photonic manufacturing capability and demonstrate the potential to impact on the development of future photovoltaic and photonic sensing technologies. In addition, energy consumption/carbon emission for the LAHT will be evaluated in comparison with existing autoclave/furnace based techniques.