Ultra-Lightweight Photovoltaic Cells on Flexible Substrates for Energy Conversion Applications

Reliable and efficient sources of energy are of critical importance for space exploration. Solar power has long been recognized as one of the most promising sources of energy for space missions since it represents one of the few renewable energy sources in space. Advances in amorphous silicon (a-Si) deposition and patterning have led to the development of ultra-light thin-film photovoltaic cells that can be rolled up for efficient storage. The main drawback of these devices is the low intrinsic mobility of a-Si, which leads to lower energy conversion efficiency. These drawbacks have thus far prevented thin-film photovoltaic cells from displacing the heavier and more rigid conventional solar cell devices that are based on single-crystal Silicon (c-Si). Standard methods for crystallizing a-Si require high temperatures that are incompatible with thin-film materials, which are often polymeric in nature. One of the most promising techniques for crystallizing silicon on flexible substrates is excimer laser crystallization, which involves using short pulses of ultraviolet emission from an excimer laser to locally heat a small area of an a-Si substrate. By scanning the laser beam in an appropriate manner over the entire substrate, large areas of single-crystal silicon can be formed. We propose to use our capabilities in excimer laser crystallization as well as our expertise in high-throughput lithography and direct batch photoablation to develop efficient, large-area, lightweight, thin-film photovoltaic devices.