An enthalpy–entropy competition strategy enables moisture-stable and scalable perovskite photovoltaics

Abstract

Scalable fabrication of perovskite solar modules is hindered by processing inconsistencies and moisture-induced degradation. Although classic coordination solvents form thermodynamically stable intermediate phases with lead iodide (PbI2) under inert gas atmospheres, they are highly hygroscopic in ambient conditions. Moreover, due to minimal entropy change, this phase is difficult to remove during annealing, leading to micropores and unwanted phases. Here we introduce an enthalpy–entropy competition strategy for scalable, humidity-tolerant perovskite printing, in which dimethyl sulfoxide/N-methylpyrrolidone is replaced by N-butylpyrrolidone. N-butylpyrrolidone forms strong carbonyl–PbI2 coordination at ambient temperatures (enthalpy-driven), yet readily dissociates on heating (entropy-driven), facilitating easier formamidinium iodide embedding and intermediate-phase protection. The strategy yields perovskite solar modules with certified power conversion efficiencies of 23.97% in a 100-cm2 rigid module and 19.71% in a flexible counterpart. Encapsulated devices retain 80% of initial performance after 1,440 hours under the double 85 condition (85 °C, 85% relative humidity), demonstrating outstanding operational durability.