Molecular Polarization-Driven Synergistic Interface Engineering for High-Performance Perovskite Solar Cells.

Abstract

The performance of inverted perovskite solar cells (PSCs) is often impeded by severe non-radiative recombination and carrier transport losses at the self-assembled monolayer (SAM)/perovskite interface, arising from inhomogeneous SAM distribution and weak interfacial bonding with the perovskite layer. To address these challenges, we introduce a universal synergistic interface engineering strategy employing 2-aminopyrimidine-4-carboxylic acid (m-APCA), a meta-substituted molecule featuring asymmetric bifunctional groups on its pyrimidine ring. These groups induce substantial molecular polarization, amplifying the dipole moment and reinforcing intermolecular π-π interactions with SAMs, thereby mitigating SAM aggregation and ensuring uniform substrate coverage. Concurrently, the strong dipole field and bifunctional chemistry of m-APCA enable robust chemical bonding with the perovskite layer, acting as nucleation sites that regulate grain growth and passivate buried interfacial defects. This dual-action approach reduces interfacial energy barriers and enhances hole transport efficiency, achieving very high efficiencies of 26.77% (certified at 26.71%), 26.08%, and 24.17% for small-area (normal bandgap), centimeter-scale (normal bandgap), and wide-bandgap PSCs, respectively. Notably, optimized PSCs demonstrate exceptional operational stability, retaining 96% of initial efficiency after 1200 h of continuous maximum power point tracking.