Quantitative Deposition Enables Dual Passivation Synergy for Efficient Inverted Perovskite Solar Cells

ABSTRACT Non‐radiative recombination at the perovskite/C ₆₀ interface is a primary culprit for the performance loss in inverted perovskite solar cells (PSCs). While integrated chemical and field‐effect passivation presents a promising solution, the lack of precise deposition control has hindered the optimization of this combined effect. Here, we achieve quantitatively controlled and uniform deposition of 1,3‐propyldiammonium diiodide (PDADI) by employing drop‐on‐demand inkjet printing. This approach allows us to unravel a clear correlation between deposition density and passivation outcome. We demonstrate that the passivation mechanism is critically governed by the deposition amount. At a low deposition density, both chemical and field‐effect passivation are suboptimal. An optimal deposition density yields the most effective synergy, maximizing defect suppression while maintaining a strong field‐effect passivation. However, excessive deposition leads to disordered molecular packing, which diminishes the field effect, induces energy‐level misalignment, and increases series resistance. Consequently, the optimally passivated device delivers a champion power conversion efficiency (PCE) of 26.1% while demonstrating outstanding stability during operation. Our study highlights the indispensability of quantitative deposition for controlling passivation mechanisms, providing a fundamental insight and a scalable pathway toward highly efficient and stable perovskite photovoltaics.