Perovskites with grain size comparable to film thickness are intensively pursued for high-efficiency solar cells. Geometrically, large grains with high crystallinity tend to form polyhedral shapes that have difficulty forming compact and smooth films. When quasi-two-dimensional RP perovskite films adopt a downward growth mode, defective contacts tend to form at their bottom interfaces with many nanocavities. This is attributed to the angular growing fronts of RP perovskite grains adopting [111] (or/and [101]) growth directions. Self-generated methylamine gas, by a replacement reaction in solution, is introduced to in situ heal these irregular nanocavities that are deeply buried in perovskite films during crystallization processes. The amount of self-generated methylamine gas should be adequately controlled to avoid the homogeneous nucleation of perovskites from a liquid perovskite-amine intermediate phase, which is a key to avoid ruining the grain size and film composition. This in situ healing strategy offers significantly enhanced charge collection efficiency and device working stability.

中文翻译：

---

用自生甲胺气体修复准二维钙钛矿薄膜中的埋孔和缺陷

具有与薄膜厚度相当的晶粒尺寸的钙钛矿被广泛用于高效太阳能电池。在几何上，具有高结晶度的大晶粒倾向于形成多面体形状，难以形成致密和光滑的薄膜。当准二维 RP 钙钛矿薄膜采用向下生长模式时，在其底部界面处往往会形成有许多纳米腔的缺陷接触。这归因于采用 [111]（或/和 [101]）生长方向的 RP 钙钛矿晶粒的角形生长前沿。通过溶液中的置换反应，自生甲胺气体被引入到原位修复这些在结晶过程中深埋在钙钛矿薄膜中的不规则纳米腔。应充分控制自生甲胺气体的量，以避免钙钛矿从液态钙钛矿-胺中间相均匀成核，这是避免破坏晶粒尺寸和薄膜组成的关键。这种原位愈合策略显着提高了电荷收集效率和器件工作稳定性。