Author Archives: nDaizhe Wang, nTengling Ye, nDongqing He, nXiaochen Sun, nYong Zhangn

Interface Engineering of Inverted Perovskite Solar Cells Using a Self‐doped Perylene Diimide Ionene Terpolymer as a Thickness‐Independent Cathode Interlayer

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Interface Engineering of Inverted Perovskite Solar Cells Using a Self-doped Perylene Diimide Ionene Terpolymer as a Thickness-Independent Cathode Interlayer†

In this study, we successfully synthesized a highly soluble, self-doping perylene imide-based ionene polymer (PNPDIN). By using it as a CIL material in inverted Perovskite Solar Cells (PerSCs), the power conversion efficiency (PCE) remarkably increased from 10.05% (without a CIL) to 16.97% (with PNPDIN). Moreover, a synergistic effect was achieved by combining PNPDIN with Bphen as a mixed CIL, leading to an outstanding PCE of 21.28% due to the favorable morphology and energy level alignment. Furthermore, the device's performance displayed excellent tolerance towards varying thicknesses of the mixed CIL, which was attributed to PNPDIN's high conductivity. Even at a film thickness of up to 37 nm, the optimized PCE remained at a high level of 20.46%. This superior mixed CIL materials may open promising avenues for efficient roll-to-roll processing of inverted PerSCs.


Comprehensive Summary

Inverted perovskite solar cells (PerSCs) are a highly promising candidate in the photovoltaic field due to their low-temperature fabrication process, negligible hysteresis, and easy integration with Si-based solar cells. A cathode interlayer (CIL) is necessary in the development of inverted devices to reduce the trap density and energy barrier between the electron transport layer (ETL) and the electrode. However, most CILs are highly thickness-sensitive due to low conductivity and poor film-forming. In this study, we report on a self-doping perylene imide-based ionene polymer (PNPDIN) used as CIL material to modify electrode in inverted PerSCs. PNPDIN exhibits high conductivity and a good solubility in polar solvent, which results in an improved power conversion efficiency (PCE) from 10.05% (device without a CIL) to 16.97%. When the blend of PNPDIN and Bphen was used as a mixed CIL, the PCE of PerSCs can be further increased to 21.28% owing to the excellent morphology and matched energy level. More importantly, the PCE of the device is highly tolerant to the thickness of the mixed CIL, which benefited from the high conductivity of PNPDIN. This development is expected to provide an excellent mixed CIL material for roll-to-roll processing efficient and stable inverted PerSCs.