Moisture-resistant perovskite solar cells: the role of 1,1′-methylenebispyridinium dichloride in enhancing stability and performance

Abstract

In this work, we explore the incorporation of 1,1′-methylenebispyridinium dichloride (DipyCl₂), which has a high acid dissociation constant (i.e. the pK_a value) of 26.4, to enhance the moisture resistance of organic–inorganic hybrid lead halide perovskite thin films. These films are critical in determining the long-term stability and practical application of photovoltaic devices. The additive DipyCl₂ facilitates moisture tolerance and defect passivation in the perovskite structure. The perovskite film with a 0.10 mol% DipyCl₂ additive significantly extended carrier lifetime to 290 ± 5.81 ns and enhanced moisture resistance, maintaining its black color even after being stored in air for 4 months. PSCs incorporating 0.10 mol% DipyCl₂ achieved an efficiency of 24.2% and retained 80% initial efficiency after 2000 hours of air exposure. This study highlights DipyCl₂ as a promising additive for improving both the stability and efficiency of PSCs, paving the way for their long-term, practical applications.