NH₄Ac boosts the efficiency of carbon-based all-inorganic perovskite solar cells fabricated in the full ambient air to 15.43%

Carbon-based all-inorganic perovskite solar cells (PSCs) have attracted tremendous attention due to the higher intrinsic stability, which is beneficial to lower fabrication costs and further commercial applications. Furthermore, for the purpose of promoting the industrialization of PSCs, it is crucial to explore preparation methods in ambient air condition. Herein, ammonium acetate (NH₄Ac) is added into the antisolvent for the first time in carbon-based all-inorganic PSCs under the full ambient air condition. It could improve the quality of perovskite films by adjusting the nucleation density and utilizing intermediate phase to retard crystallization. By regulating the concentrations of NH₄Ac, the perovskite films with dense and pinhole-free, large grain size, few grain boundaries and less defects are finally formed. Ultimately, the optimal device achieved a high efficiency of 15.43%, which is a new record value for carbon-based all-inorganic PSCs.