Factors Limiting the Operational Stability of Tin–Lead Perovskite Solar Cells

Abstract

Tin–lead perovskite solar cells (TLPSCs) have emerged as one of the most efficient photovoltaic technologies. However, their stability under operational conditions (ambient air, temperature, bias, and illumination) is lagging behind their sharp efficiency increase, restraining their further development. In this Focus Review, we provide insights into the degradation mechanisms of tin–lead perovskites and summarize the principal factors that currently limit the operational stability of TLPSCs. Specifically, perovskite composition and the device architecture stand out as critical aspects governing their sensitivity toward stressors such as temperature and light. We discuss several strategies to overcome these limitations and emphasize the adoption of standardized methods to quantify the lifetime of a device. We further propose using various characterization techniques to identify possible device failure mechanisms. We expect this Focus Review to assist in the progress toward the development of efficient and stable perovskite devices.

On the Durability of Tin‐Containing Perovskite Solar Cells

“…[19,20] This particular bandgap range is appealing in solar cell applications because it can effectively harness the solar radiation spectrum to achieve the maximum theoretical efficiency limits of a singlejunction solar cell. [21] Additionally, the narrow-bandgap Sn-Pb perovskites can be paired with wide-bandgap perovskite to fabricate ultrahigh efficiency all-perovskite tandem solar cells. [22][23][24] Nevertheless, the device efficiency and stability of Sncontaining PSCs significantly lag behind their Pb-based counterparts.…”

Surface Dedoping for Methylammonium-Free Tin–Lead Perovskite Solar Cells

“…As reported, I − ion intercalation leads to numerous voids of C 60 ETL and causes irreversible degradation of the Ag electrode, seriously deteriorating the device performance. 10,40 In striking contrast, lower concentration and shallower penetration of the I − ion in the C 60 layer and Ag electrode were observed in aging target devices, suggesting the ameliorated I − ion migration during the aging process. Meanwhile, the target device exhibited enhanced resistance to Ag diffusion relative to the control device, benefiting the stability enhancement of devices.…”

“…Environmental species, such as oxygen/water molecules, preferentially coordinate with the undercoordinated ions caused by fragile Sn−I frameworks to trigger Sn 2+ oxidation and phase transition. 10,11 A high-quality surface at the contact interface is crucial to achieving superior device performance. Considering the charge transport in the vertical direction of PSCs, the band misalignment and interfacial recombination that originate from surface imperfections predominantly limit the carrier 30% and excellent operational stability.…”

“…Moreover, perovskite microstructure degradation always initiates at the surface due to the metastable structural disorder. Environmental species, such as oxygen/water molecules, preferentially coordinate with the undercoordinated ions caused by fragile Sn–I frameworks to trigger Sn 2+ oxidation and phase transition. , …”

Regulating Surface Heterogeneity Maximizes Photovoltage and Operational Stability in Tin–Lead Perovskite Solar Cells

“…3,4 Identifying main surface vulnerabilities and implementing suitable modifications is crucial to minimize defects and ensure the stability of Sn−Pb perovskite solar cells (PSCs). 5,6 Various surface passivation approaches have been explored to enhance the performance and stability of Sn−Pb PSCs. 7,8 For instance, Li et al improved the moisture stability of the cells by introducing a quasi-two-dimensional (2D) heterostructure using 2-(4-fluorophenyl)ethylammonium iodide on the three-dimensional (3D) perovskite counterparts.…”