Interface Engineering in Perovskite Solar Cells by Low Concentration of Phenylethyl Ammonium Iodide Solution in the Antisolvent Step

In spite of the outstanding properties of metal halide perovskites, its polycrystallinenature induces a wide range of structural defects that results in charge losses thataffect thefinal device performance and stability. Herein, a surface treatment is usedto passivate interfacial vacancies and improve moisture tolerance. A functionalorganic molecule, phenylethyl ammonium iodide (PEAI) salt, is dissolved with theantisolvent step. The additive used at low concentration does not induce formationof low-dimensional perovskites species. Instead, the organic halide species pas-sivate the surface of the perovskite and grain boundaries, which results in aneffective passivation. For sake of generality, this facile solution-processed synthesiswas studied for halide perovskite with different compositions, the standardperovskite MAPbI3, and double cation perovskites, MA0.9Cs0.1PbI3andMA0.5FA0.5PbI3, increasing the average photoconversion efficiency compared tothe reference cell by 18%, 32%, and 4% respectively, observed for regular, n-i-p,and inverted, p-i-n, solar cell configurations. This analysis highlights the generalityof this approach for halide perovskite materials in order to reduce nonradiativerecombination as observed by impedance spectroscopy