2021 Advanced Functional Materials (IF 18.808):
How does the molecular stacking order improve the efficiency of perovskite solar cells?

　　In October 2021, Advanced Functional Materials (IF 18.808) published a study. The electron transport layer (ETL) plays an important part in extracting electron carriers while optimizing the perovskite/electrode interface contact in planar heterojunction perovskite solar cells (PVSCs). Although various ETLs are used to design for efficient PVSCs, there is almost no research on the effect of molecular stacking order on device performance. In this study, poly (ethylene-co-vinyl acetate) (EVA) was used as the [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) solution additive. The strong binding energy between EVA and PC₆₁BM can promote the molecular stacking order of ETLs to reduce the morphological inhomogeneity, possess a matched energy level, block ion migration, and improve the water-oxygen barrier of perovskite devices.

　　Enlitech’s Solar Simulator was used in this study to assist in the measurement of experimental data. It was found that the blade-coated MAPbl₃-based PVSCs achieve a power conversion efficiency (PCE) of 19.32%, with positive reproducibility and negligible hysteresis. In addition, under inert and ambient conditions (52% humidity) without encapsulation, storage for 1500 hours, maintaining 90% and 80% of the initial PCE. Using this strategy, the champion PCE of CsFAMA-based PVSCs was increased to 20.33%. These findings show that the adjustment of molecular stacking order is an effective method for optimizing the interface charge-carrier recombination in PVSCs. It satisfies the demand for high-performance ETL in large-area PVSC and promotes the upgrade of fabrication technology to practical applications.

　　Enlitech’s solar simulator complies with international standards. With KA-6000 software, it provides a short-term monitoring of time changes to prove the stability of the perovskite solar cell!