Rosemary C. Bramante

Nickel oxide (NiO _x ) is a common hole transport layer (HTL) in perovskite photovoltaics, but the chemical reactivity of NiOx surfaces accelerates degradation when contacting perovskites. We developed an ultrathin, conformal tin oxide (SnO _x ) interlayer to suppress interfacial reactivity between NiO _x and perovskite. SnO _x is typically an electron transport layer, but we show that the energy alignment can be modified for hole extraction using molecules with dipoles. This synergy yielded high efficiency in perovskite photovoltaic devices and showed an ~10x improvement in T 90 lifetime in open-circuit conditions under AM1.5G at 65°C. This structure also improves resilience to thermomechanical durability, as minimodules retained 95.7% of their initial performance after 1000 thermal cycles (−65° to 85°C), highlighting the importance of interfaces for robust perovskite photovoltaic modules.

Parasitic optical losses from interlayers in 4-Terminal Perovskite/c-Si tandem photovoltaics device reduce charge generation and impact the device performance. Here, optical simulations of the experimental device are performed, and detailed optical analysis help identify the source of losses and mitigate them by optimizing the thickness of the TCO layers from the tandem top cell.