An ultra-low-consumption dilution strategy for high-performance inverted perovskite solar cells.

Despite significant breakthroughs in power conversion efficiency (PCE) and operational stability of perovskite solar cells (PSCs), their development remains challenged by lead toxicity risk and high production costs. This study introduces a process-efficient dilution strategy using acetonitrile for the perovskite precursor solution, which reduces the precursor concentration from the conventional 1.4 M to an ultra-low 0.28 M. This approach establishes an eco-friendly and cost-effective processing method, substantially mitigating the risk of lead while lowering raw material consumption. Crucially, acetonitrile regulates nucleation kinetics to enable dense, high-quality perovskite films, yielding champion devices with a PCE of 25.40%. Stability assessments demonstrate exceptional robustness that unencapsulated devices retain 80% of initial PCE after 1224 h of storage in N atmosphere and 82% after 800 h of continuous operation at 30 ± 10% relative humidity. By concurrently resolving toxicity, cost, and performance optimization challenges through solvent engineering, this work provides a fundamental advance for sustainable development of perovskite photovoltaics.