Ren Zhilin, Yuan Zhengtian, Ovčar Juraj, Leung Tik Lun, He Yanling, Ho-Baillie Anita W Y, Lončarić Ivor, Popović Jasminka, Djurišić Aleksandra B
Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong SAR.
CNR-IOM, Via Bonomea 265, 34136 Trieste, Italy.
iScience. 2025 Mar 4;28(4):112154. doi: 10.1016/j.isci.2025.112154. eCollection 2025 Apr 18.
2D lead halide perovskites are used to improve device operational stability due to increased environmental stability and reduced ion migration compared to 3D perovskites. However, the relationship between the 2D perovskite stability under illumination and spacer cation is still not well understood. Thus, we examine photoinduced halide segregation (PHS) in different 2D mixed-halide perovskites and show that PHS is suppressed in the materials which have photostable bromide halide phase. As the spacer cations provide the barrier to ion migration in 2D perovskites, PHS would be facilitated by the loss of spacer cations through their interactions with various mobile oxidized halide species, resulting in organic ammonium deprotonation and spacer cation vacancy formation. The existence of a photostable APbBr phase, which does not exhibit spacer cation loss, results in the suppression of PHS in 2D mixed halide perovskites due to reduced spacer vacancy formation and consequently reduced halide ion migration under illumination.
与三维钙钛矿相比，二维卤化铅钙钛矿具有更高的环境稳定性和更低的离子迁移率，因此被用于提高器件的运行稳定性。然而，二维钙钛矿在光照下的稳定性与间隔阳离子之间的关系仍未得到很好的理解。因此，我们研究了不同二维混合卤化钙钛矿中的光致卤化物偏析（PHS），结果表明，在具有光稳定溴化物卤化物相的材料中，PHS受到抑制。由于间隔阳离子为二维钙钛矿中的离子迁移提供了屏障，间隔阳离子与各种可移动的氧化卤化物物种相互作用而损失，会促进PHS，导致有机铵去质子化和间隔阳离子空位形成。由于不存在间隔阳离子损失，光稳定的APbBr相的存在，减少了间隔空位的形成，从而降低了光照下卤离子的迁移，导致二维混合卤化钙钛矿中的PHS受到抑制。
