Imec Perovskite/Silicon Tandem Cell Achieves 27.1 Percent Efficiency

Belgian-based research and innovation hub Imec, within the partnership of EnergyVille, reported that its Perovskite/silicon tandem photovoltaic cell achieved a power conversion efficiency of 27.1 percent. This result beats the most efficient standalone silicon solar cell. imec researchers speculate that further engineering of the Perovskite material could bring efficiencies of over 30%.

Perovskite microcrystals are a promising material for high-performance thin-film solar cells. Also, they can be made into thin, light, semitransparent modules that can achieve a high power conversion efficiency, are inexpensive to produce, and have a high absorption efficiency for sunlight. The one drawback so far has been their reliability. The researchers at imec note that because they can be made semitransparent, perovskite solar cells can be placed on top of silicon solar cells.

Imec’s new record tandem cell features a 0.13 cm² spin-coated Perovskite cell developed within the Solliance cooperation stacked on top of a 4 cm² industrial interdigitated back-contact (IBC) silicon cell in a 4-terminal configuration. This configuration is known to have a higher annual energy yield compared to a 2-terminal configuration. Additionally, they scaling up the tandem device using a 4 cm2 perovskite module on a 4 cm2 IBC silicon cell to achieved a tandem efficiency of 25.3%, surpassing the stand-alone efficiency of the silicon cell.

Manoj Jaysankar, a doctoral researcher at imec/EnergyVille, said, “We have been working on this tandem technology for two years now, and the biggest difference with previous versions is in the engineering and processing of the Perovskite absorber, tuning its bandgap to optimize the efficiency for tandem configuration with silicon.”

“Adding Perovskite on top of industrial silicon PV may prove to be the most cost-effective approach to further improve the efficiency of photovoltaics,” concludes Tom Aernouts, group leader for thin-film photovoltaics at imec/EnergyVille. “Therefore, we invite all companies in the PV value chain that are looking into higher efficiencies, to partner with us and explore this promising path.”