Genshun Wang

Partial shading is a common condition in the outdoor deployment of photovoltaic modules, potentially causing significant power loss and severe thermal damage. Limitations of existing solutions in balancing effect and cost necessitate a thorough solution, which involves a fundamental redesign at the solar cell level. Here we propose a cell architecture featuring integrated reverse conductivity to address this challenge. We derive the design principles by drawing inspiration from bypass diodes, and manage to introduce spatially uniform reverse conduction channels to the cell. These engineered in-cell channels exhibit bias-dependent switching behavior that enables reverse conductivity of the cell without compromising power conversion efficiency. The underlying mechanisms and modulation strategies of the cell are elucidated. Prepared photovoltaic modules composed of the proposed cells demonstrate clear advantages in thermal management and power output stability under partial shading conditions. The design principles and conduction channel strategies in this work also provide insight for other passivating-contact solar cells. The in-cell design approach offers merits in reliability, cost, and integration, and holds promise for next-generation photovoltaic technologies.

Silicon solar cells are essential for sustainable energy but remain limited by efficiency losses, particularly in the fill factor^1,2,3. Here we develop a hybrid interdigitated back-contact solar cell that combines advanced all-surface passivation with laser-treated tunnelling contacts. This approach achieves a power conversion efficiency of 27.81%, approaching 95% of the theoretical limit⁴. By integrating high- and low-temperature processes, we suppress recombination and enhance contact performance, achieving a fill factor of 87.55%—nearly 98% of the theoretical limit. A model links the ideality factor to carrier loss mechanisms, elucidating carrier recombination in both the bulk and the surface and clarifies key fill factor losses owing to recombination. These innovations provide both experimental and theoretical advances towards scalable, high-efficiency silicon photovoltaics.