Low-temperature ALD-grown SnO_x interlayer for scalable and stable p–i–n perovskite solar cells and modules

Inverted p–i–n perovskite solar cells (IPSCs) offer promise for next-generation photovoltaics. However, IPSCs utilizing solution-processed PC₆₁ BM as the electron transport layer (ETL) remain less interface-optimized than conventional n–i–p configurations, restricting their efficiency, stability, and scalability. In this work, we introduce an ultrathin atomic-layer-deposited SnO_x (ALD-SnO_x) film, fabricated at a low temperature (80 °C), as a versatile interfacial modifier to address these shortcomings. This scalable, vapor-phase approach directly addresses the core instability in p–i–n architectures, effectively remedies morphological defects such as pinholes and phase segregation in PC₆₁ BM, significantly enhancing interfacial contact and suppressing charge recombination. Consequently, the champion IPSC incorporating a 10 nm ALD-SnO_x interlayer yields a power conversion efficiency (PCE) of ∼19.2%, representing a remarkable 58% improvement over control devices (PCE ∼11.3%). The ALD-SnO_x interlayer effectively enhances moisture resistance, giving the IPSCs excellent environmental stability. Additionally, the redesigned IPSCs show scalability by effectively generating a large-area (∼12.1 cm²) mini-module with a high PCE (∼14.1%). These findings demonstrate the immense potential of this interfacial engineering approach for the commercial production of scalable, stable, and effective IPSCs.