Surface Passivation with Diaminopropane Dihydroiodide for p-i-n Perovskite Solar Cells with Over 25% Efficiency

At present, one of the major factors limiting the further improvement of inverted (p-i-n) perovskite solar cells (PSCs) is trap-assisted non-radiative recombination at the perovskite/electron transporting layer (ETL) interface. Surface passivation with organic ammonium salt is a powerful strategy to improve the performance of PSCs. Herein, an effective method by using propylamine hydroiodide (PAI) and 1,3-diaminopropane dihydroiodide (PDADI) is reported to modify the perovskite/ETL interface. These two ammonium salts do not form new perovskite but directly passivate the defects on the perovskite surface after annealing. The results show that the PDADI-modified perovskite films possess a lower surface defect density and less non-radiative recombination as well as improved charge carrier transport. Based on this strategy, the PDADI-modified p-i-n PSCs deliver an impressive efficiency of 25.09% (certified 24.58%) with an open-circuit voltage of 1.184 V. Furthermore, the unencapsulated PDADI-modified PSCs also exhibit good storage stability, retaining 91% of initial PCE at 65 degrees C in a N2 glove box for 1300 h. This strategy provides an efficient route to fabricate highly efficient and stable inverted p-i-n structured PSCs. 1,3-diaminopropane dihydroiodide (PDADI) is introduced to modify the perovskite/electron transporting layer (ETL) interface. Based on this strategy, the PDADI-modified p-i-n perovskite solar cells deliver an impressive efficiency of 25.09% (certified 24.58%) at the laboratory scale (0.071 cm2) with an open-circuit voltage of 1.184 V.image