Perovskite-TOPCon Tandems Are Catching Up!

Our article “Over 31%-efficient perovskite–TOPCon solar cells enabled by AlO_x-based hydrogenation and front sub-micron texturing” is now published in EES Solar. In this work, we demonstrate high-efficiency perovskite–silicon tandem solar cells using double-sided tunnel oxide passivated contacts (TOPCon²) bottom cells, achieving 30.2% efficiency on both sides flat and 31.3% on front-textured devices. The former is enabled by high passivation quality on flat surfaces and the latter by enhanced optical performance. These results highlight that TOPCon² is a promising platform for scalable tandem integration beyond silicon heterojunction-based bottom cells.'

We are excited to share our latest publication in EES Solar:
“Over 31%-efficient perovskite–TOPCon solar cells enabled by AlOx-based hydrogenation and front sub-micron texturing”

Key innovations:

1. Front sub-micron texturing delivers superior optical response and light trapping.
2. ALD-AlOx-based hydrogenation preserves excellent passivation quality, especially on textured surfaces.

These innovations enabled open-circuit voltages and current densities that rival those of SHJ-perovskite tandem counterparts, positioning TOPCon–perovskite tandems as a strong contender for industrial deployment.

''As conventional crystalline silicon (c-Si) solar cells approach their efficiency limits, perovskite–silicon tandem solar cells have emerged as the next frontier in photovoltaics, pushing efficiencies beyond 30%. This work significantly advances the field by demonstrating highly efficient perovskite–TOPCon2 silicon tandem devices, achieving a remarkable 31.3% efficiency on front-textured cells. The key breakthrough lies in optimizing TOPCon2 cells as the bottom cell platform, which offers compatibility with existing manufacturing lines. Crucially, the research uses an AlOx-based hydrogenation method. This method overcomes the limitations of conventional processes by preventing damage to the sensitive tunnel oxide layer during fabrication, particularly for textured surfaces. This allows for superior passivation quality and improved light trapping, paving the way for more efficient and cost-effective solar energy conversion.''

Funding
Moreover, we are grateful to the Swiss Federal Office of Energy SFOE for support through our project, BESTOBOT.