Organic Bromide Salts Interface Modification for High‐Efficiency Perovskite Solar Cells with Printed Carbon Electrode

Perovskite solar cells (PSCs) using carbon as the counter electrode fabricated through a low‐temperature full solution‐process method can significantly simplify the preparation process and reduce production cost. Herein, a high‐performance PSC is presented with printed carbon electrode and dopant‐free poly(3‐hexylthiophene) (P3HT) is employed as hole transport materials. Different organic bromide salts are employed to modify the perovskite/P3HT interface to further enhance the performance. As a result, methylammonium bromide (MABr) modification significantly enhances the device open‐voltage ( V oc ) and fill factor (FF) by reducing interface defects and facilitates charge transport. A champion power conversion efficiency (PCE) of 19.22% ( V oc of 1.118 V, FF of 0.765, and short‐circuit current of 22.48 mA cm −2 ) is achieved with MABr modification. The unencapsulated devices maintain 96% of the initial efficiency after storage for 3600 h and 88% after thermal treatment at 70 °C for 1200 h. Additionally, perovskite solar modules are also prepared based on printing and interface passivation route with PCE reaches 13.20%. These results represent an important progress in the enhancement of device PCE and up‐scaling of PSCs with cost‐effective, stable, and printed carbon electrode.