An amino-phthalocyanine additive enhances the efficiency of perovskite solar cells through defect passivation in mixed-halide films

Abstract

Although perovskite solar cells (PSCs) can be easy to process and display exceptional optoelectronic properties, the presence of defects and poor control over crystallization can adversely affect their efficiency and long-term stability. In this study, we employed iron(II)-2,9,16,23-tetraamino-phthalocyanine (FeTAP) as a small-molecule additive capable of defect passivation in a mixed-halide perovskite (MHP). In particular, we used an additive engineering treatment protocol to introduce FeTAP into the MHP layer to significantly suppress perovskite defects, improve charge extraction, and inhibit perovskite degradation. A PSC incorporating a FeTAP-modified perovskite layer exhibited a power conversion efficiency (PCE) of 18.81% and retained 72.5% of its initial PCE after storage for 30 days. Thus, adding FeTAP to the MHP film significantly enhanced the efficiency and stability of the resulting PSC. Iron(II)-2,9,16,23-tetraamino-phthalocyanine (FeTAP), when used as a small-molecule additive in the precursor solution of a mixed-halide perovskite, enhances the photovoltaic properties of resulting planar perovskite solar cells. • We have added iron(II)-2,9,16,23-tetraamino-phthalocyanine (FeTAP), a small molecule capable of interacting with a mixed-halide perovskite (MHP), during the fabrication of n–i–p PSCs. The power conversion efficiencies were improved for our tested PSCs incorporating FeTAP. • The morphologies of the mixed-halide perovskite films prepared with the small-molecule additive FeTAP were superior to that of the pristine control perovskite film, suggesting that the FeTAP units interacted with undercoordinated Pb 2+ ions within the films, leading to higher-performance PSCs. • Incorporating the additive in the perovskite precursor solution resulted in perovskite films of superior film quality and with lower numbers of defects, thereby enhancing the photovoltaic performance of resulting PSCs and providing higher power conversion efficiencies.