Adam Printz1 Nicholas Rolston1 Stephen Hamann1 Oliver Zhao1 Olav Solgaard1 Reinhold Dauskardt1

1, Stanford University, Stanford, California, United States

Building on our recent advancements addressing the mechanical instability of perovskite solar cells using scaffold-reinforced compound solar cells (CSCs) in which planar perovskite devices are partitioned into many smaller microcells by a reinforcing scaffold, we have designed a new architecture with integrated light management for highly efficient and mechanically robust perovskite solar cells. The CSCs exhibited a fracture resistance of ~13 ± 3 J m–2—a 30-fold increase over previously reported planar perovskite devices. However, device efficiency decreased based on the photo-inactivity of the scaffold material, where the short-circuit current scaled inversely with the scaffold dimensions (i.e., larger scaffolds resulted in lower current and efficiency). In this work, we demonstrate how efficiency losses can be mitigated using a robust and low-cost light management system, which directs light away from the scaffolds and into the perovskite microcells. This architecture is material independent and compatible with all perovskite solar cell compositions along with exhibiting some self-tracking ability to reduce system losses in efficiency at lower illumination angles. Device performance is shown to be stable under continuous illumination, and the low concentrated light is thus not deleterious to the perovskite. These developments are significant steps toward demonstrating robust perovskite solar cells with major improvements in reliability and service lifetimes while maintaining high efficiency that can ultimately compete with CIGS, CdTe, and c-Si cells.