A solar cell from Professor Ho-Baillie's lab
Solar cells convert solar energy into electricity using semiconductors. While silicon is the semiconductor material being used in the current solar technology, perovskites have emerged as a promising alternative candidate. Perovskites are crystal structures made from mineral compounds, and the metal halide version is particularly useful for solar-cell applications. The efficiencies of perovskite solar cells are approaching those of silicon solar cells.
This project will focus on stacking perovskite on top of silicon to form a tandem solar cell, rather than using silicon on its own.
“The idea of this stacking is to convert more energy from the sun to electrical power,” said Professor Ho-Baillie. “The efficiency that can be achieved by a perovskite-silicon tandem in a laboratory is now over 30 percent, while the highest efficiency for a silicon cell on its own is just below 27 percent in the laboratory and around 23 percent commercially.
“There isn’t much room for silicon to improve because its theoretical limit is only 30 percent – but for perovskite-silicon tandem, it is 40 percent.”
The cell design is the “future” of solar technology, according to Professor Ho-Baillie, but there are a few steps to tackle before reaching that endpoint.
“To make them the main commercial option, we need to improve the durability of these cells – especially under the combination of thermal and light stress,” said Professor Ho-Baillie. “We also need to develop industry-relevant manufacturing processes that are cost-effective.
“Lastly, we need to develop technologies of encapsulating and packaging the tandem cells to larger solar panels. These panels, not just the cells themselves, also have to be durable and highly efficient.”