From Monolayers to Matrices: Redefining Buried Interfaces in Scalable Perovskite Photovoltaics
Metal halide perovskite solar cells (PSCs) have achieved power conversion efficiencies exceeding 27%, rivaling crystalline silicon photovoltaics. Among device architectures, the inverted p-i-n configuration offers excellent reproducibility, negligible hysteresis, and compatibility with silicon bottom cells, making it promising for scalable tandem integration. As the field shifts toward industrial viability, key challenges focus on interfacial stability, process reproducibility, and large-area manufacturability. The buried interface between the perovskite absorber and charge transport layers dictates nucleation, crystallization, charge extraction, and recombination dynamics. Imperfect interfacial contact or mismatched energy alignment leads to trap states, increased nonradiative recombination, and rapid degradation. Self-assembled monolayers (SAMs) have revolutionized interface control, offering tunable energy levels, minimized parasitic absorption, and reduced defects. However, SAM-based interfaces face scale-up challenges due to molecular aggregation, incomplete coverage, and hydrophobicity, causing nonuniform nucleation and pinhole formation. Co-assembled monolayers (Co-SAMs) have been explored but remain limited to small areas. Addressing this bottleneck, Zhao et al. proposed a 'SAM-in-matrix' strategy embedding SAM molecules within a tris(pentafluorophenyl)borane (BCF) matrix. This BCF framework disrupts π–π stacking, suppressing aggregation and producing an amorphous, uniform, and highly wettable hole transport layer, potentially enabling scalable manufacturing.