Molecular Integration Strategy Enables Simultaneous Modulation of Crystal Growth and Interfacial Energy Loss for...

Severe interfacial energy loss and inferior crystal quality remain key limitations for high-performance perovskite solar cells (PSCs). Herein, we report a multifunctional molecule, 1,3-propanediamine dimercaptoacetate (PDA(AcSH)₂), designed through a molecular-integration strategy to address these challenges simultaneously. The PDA²⁺ cations preferentially accumulate at the perovskite/C₆₀ interface, establishing a field-effect passivation that suppresses interfacial contact induced non-radiative recombination. Meanwhile, the AcSH^- anions are homogeneously distributed throughout the perovskite layer, mediating crystal growth and passivating charged traps via dual binding of ─SH and ─COO^- groups. The reducible ─SH groups in AcSH^- also convert photo-thermally generated I₂/I₃ ^- species into I^-, forming reversible S─S dimers that photodecompose under UV light illumination to regenerate ─SH groups. This enables a self-sustaining redox cycle for dynamic defect healing and enhances both precursor and film stability. Consequently, the optimized small-area (0.09-cm²) device achieves impressive efficiency of 26.88% and a non-radiative voltage loss of only 64 mV. The strategy is readily scalable, delivering efficiencies of 24.92% and 22.73% for 1-cm² device and 12.96-cm² mini-module, respectively. This work highlights the effectiveness of rational molecular design in mitigating both bulk and interfacial energy losses, paving the way for the next generation of high-performance, stable, and scalable PSCs.