Li Jialiang, Shi Chenyu, Geng Mengqi, Mao Jianming, Jiang Le, Lu Dan, Xu Tingting
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China.
Qinghai Huanghe Hydropower Development Co., Ltd. Xi'an Solar Power Branch, Xi'an, Shaanxi 710100, China.
ACS Appl Mater Interfaces. 2025 Apr 16;17(15):22831-22840. doi: 10.1021/acsami.5c02483. Epub 2025 Apr 6.
High defect density and low stability remain significant obstacles in the development of efficient and stable 3D perovskite solar cells (PSCs), while 3D/2D hybrid PSCs have emerged as promising candidates due to their excellent environmental tolerance. However, the performance of 3D/2D PSCs might be further limited by carrier transport within the films caused by quasi-2D phases with multiple n-values. Herein, precrystallized 2D phenylethylamine lead iodide (PEAPbI) crystals and methylammonium chloride (MACl) were introduced into the bulk phase of methylammonium lead iodide (MAPbI) to improve crystal quality and growth orientation. During the film formation process, 2D PEAPbI delayed crystal nucleation and formed a 3D/2D mixed film. The as-formed type-II band alignment in the 2D/3D heterojunction film restricts the movement of charge carriers within the 3D phase lattice, avoiding the risk of being trapped by defects at the grain boundaries. Additionally, MACl facilitates vertical crystal growth, enlarging grain size and the thickness of perovskite films. Under the combined effect of 2D PEAPbI and MACl, the power conversion efficiency (PCE) of the carbon-based PSCs increased from 10.53% to 16.07%. The unpackaged devices retained 90% of their initial PCE after storage for 30 days at room temperature and 40% relative humidity. These findings not only provide a facile way for the crystal tuning and defect passivation by low dimensional perovskites, but also give new insights into constructing efficient 3D/2D types of carbon-based PSCs.
高缺陷密度和低稳定性仍然是高效稳定的三维钙钛矿太阳能电池（PSC）发展中的重大障碍，而三维/二维混合PSC由于其优异的环境耐受性已成为有前景的候选者。然而，三维/二维PSC的性能可能会受到具有多个n值的准二维相导致的薄膜内载流子传输的进一步限制。在此，将预结晶的二维苯乙胺碘化铅（PEAPbI）晶体和甲基氯化铵（MACl）引入到甲基碘化铅（MAPbI）的本体相中，以提高晶体质量和生长取向。在薄膜形成过程中，二维PEAPbI延迟了晶体成核并形成了三维/二维混合薄膜。在二维/三维异质结薄膜中形成的II型能带排列限制了电荷载流子在三维相晶格内的移动，避免了被晶界处的缺陷捕获的风险。此外，MACl促进垂直晶体生长，增大了钙钛矿薄膜的晶粒尺寸和厚度。在二维PEAPbI和MACl的共同作用下，碳基PSC的功率转换效率（PCE）从10.53%提高到了16.07%。未封装的器件在室温及40%相对湿度下储存30天后仍保留其初始PCE的90%。这些发现不仅为通过低维钙钛矿进行晶体调控和缺陷钝化提供了一种简便方法，也为构建高效的三维/二维型碳基PSC提供了新的见解。
