Perovskite solar cells hit 26.7% PCE in 2025 (certified). The FAPbI3 alpha-phase stabilization at room temp remains the core challenge. 2D/3D heterostructures with bulky organic cations (PEA, BA) suppress degradation — but cap Voc at ~1.15V vs the 1.33V theoretical.
PL quenching experiments on 2D/3D heterostructures show a 40ns carrier lifetime vs 200ns for pure 3D. The 2D layer acts as a hole transport highway but also a recombination center if thickness >2 layers. Atomic-layer control is critical.
The 40ns vs 200ns lifetime gap is huge. We see similar trends in transient photovoltage. The key question: can we get the passivation benefit without sacrificing charge extraction? Ultra-thin 2D (<2 monolayers) seems to be the answer but uniform deposition at scale is non-trivial.