Self-assembled nanophotonic structures for light trapping in solar cells

Self-assembled nanophotonic structures for light trapping in solar cells can help with the critical task of reducing $/W for large scale applications. In conventional wafer-based solar cells, material alone constitutes more than half of the cost. Thin-film solar cells have become an attractive solution in recent years due to a drastic decrease in material consumption by 100x. The trade-off, however, is that their efficiency is limited by the thickness of the cells which is insufficient to absorb all the sunlight. Light trapping is needed to increase the optical path length of sunlight in these thin-film solar cells in order to improve the efficiency. In this research we are investigating self-assembled nanophotonic structures integrated on the backside of thin-film solar cells for sunlight trapping. The nanophotonic structure diffracts the incident sunlight into oblique angles so that it propagates laterally in the thin films and gets completely absorbed. Recent work demonstrated nanophotonic structures using self-assembled porous anodic aluminum oxide as a fabrication template for effective light trapping.

Faculty contact: Jifeng Liu