Comprehensively Improved the Performance of Carbon‐Based Printed Mesoscopic (FA)CsRbPbI3 Solar Cells by 3‐Pyridine Formamide

Excellent stability, low costs, and printability are the most significant features of printable mesoscopic perovskite solar cells (p‐MPSCs). However, the introduction of carbon electrodes reduces the cost of production while causing severe voltage losses within the p‐MPSCs. Herein, formamidine (FA), cesium, and rubidium are selected as A‐site cations (or cationic groups) in perovskite films, and nicotinamide (3‐pyridine formamide, NTM) is introduced as an additive to modify the perovskite films for the preparation of p‐MPSCs. The introduction of NTM can effectively passivate the crystal defects of perovskite films filled in the triple mesopores (mesoscopic TiO 2 /ZrO 2 /C), which enhances the pore filling and improves the carrier transportation and extraction efficiency. In addition, the amide group can effectively enhance the work function of the perovskite films and further increase the open‐circuit voltage ( V OC ) of the p‐MPSCs. Consequently, major benefitting from the significant increase in V OC (from 880 to 970 mV), the power conversion efficiency (PCE) of the NTM‐modified p‐MPSCs is improved up to 16.36%, which is nearly 20% improvement compared with the 14.36% of the control devices. In addition, the unencapsulated modified NTM‐modified (FA)CsRbPbI 3 p‐MPSCs show excellent stability in air by maintaining 85% of the initial PCE after 90 days of storage.