Wei Zhanhua & Xie Liqiang AEM: Reducing the surface reactivity of alkylammonium passivation molecules enables high-efficiency perovskite solar cells
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Non-radiative recombination at the interface of perovskite solar cells (PSCs) is a key issue limiting device efficiency and stability. The most advanced surface passivation strategies often utilize alkyl ammonium halides to suppress non-radiative recombination in PSCs, but their high surface reactivity leads to transformation into two-dimensional perovskites under operating conditions, limiting the passivation effect and charge transfer in PSCs.
Wei Zhanhua and Xie Liqiang et al. at Huaqiao University synthesized a non-halide ionic salt, 1-naphthylmethylammonium formate (NMACOOH), for surface passivation of perovskite thin films. Compared to traditional 1-naphthylmethylammonium iodide, NMACOOH treatment inhibited the formation of two-dimensional perovskites and formed thermally stable PbI2-NMACOOH adducts on the perovskite surface.
Surface characterization showed that NMA+ can passivate cation vacancies of 3D perovskites, while HCOO- can passivate metal Pb0 and halide vacancy defects. As a result, non-radiative recombination in PSCs was suppressed, yielding a high open-circuit voltage of 1.19 V. Ultimately, PSCs with efficiency as high as 24.75% and improved long-term stability (98% of initial efficiency after storage for 1800 hours) were obtained. In addition, the NMACOOH passivated devices also exhibited strong operational stability, retaining 83% of initial efficiency after working continuously under 1 sun for 658 hours.
The measurements in this study were performed using Enlitech 3A and QER666 products.
Zheng, L., Shen, L., Fang, Z., Song, P., Tian, W., Chen, J., Liu, K., Luo, Y., Xu, P., Yang, J., Tian, C., Xie, L., Wei, Z., Reducing the Surface Reactivity of Alkyl Ammonium Passivation Molecules Enables Highly Efficient Perovskite Solar Cells. Adv. Energy Mater. 2023, 2301066.