Zhang Chi, Zhang Yao, Wang Xingtao, Shi Congbo, Lin Zizhen, Zhao Zhiguo, Zhao Dongming, Li Menglei, Chen Xiongfei
Huaneng Clean Energy Research Institute, Beijing 102209, China.
State Key Laboratory of Modern Optical Instrumentation, Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
ACS Appl Mater Interfaces. 2023 Dec 27;15(51):59946-59954. doi: 10.1021/acsami.3c14834. Epub 2023 Dec 16.
In the past decade, two-dimensional (2D) perovskite surface treatment has emerged as a promising strategy to improve the performance of three-dimensional (3D) perovskite solar cells (PSCs). However, systematic studies on the impact of organic spacers of 2D perovskites on charge transport in 2D/3D PSCs are still lacking. Here, using 2D perovskite film/C heterostructures with different organic spacers [butylamine (BA), phenylethylamine (PEA), and 3-fluorophenethylamine (m-F-PEA)], we systematically investigated the carrier diffusion and interfacial transfer process. Using a 2D perovskite film with a thickness of ∼7 nm, we observed subtle differences in electron transfer time between 2D perovskites and C layers, which can be attributed to limited thickness and similar electron coupling strength. However, with the thickness of 2D perovskite increasing, electron transfer efficiency in the (BA)PbI/C heterostructure exhibits the most rapid decrease due to poor carrier diffusion of (BA)PbI caused by stronger exciton-phonon interactions compared to (PEA)PbI and (m-F-PEA)PbI in thickness-dependent charge transfer research. Meanwhile, the fill factor of 2D/3D PSC treated with BAI exhibits the most rapid decrease compared to PEAI- and m-F-PEAI-treated 2D/3D PSCs with the concentration increase of passivators. This study indicates that it is easier to enhance open-circuit voltages and minimize the decrease of fill factor by increasing the concentration of passivators in 2D/3D PSCs when using passivators with a rigid molecular structure.
在过去十年中，二维（2D）钙钛矿表面处理已成为一种有前景的策略，用于提高三维（3D）钙钛矿太阳能电池（PSC）的性能。然而，关于二维钙钛矿的有机间隔层对二维/三维PSC中电荷传输影响的系统研究仍然缺乏。在此，我们使用具有不同有机间隔层[丁胺（BA）、苯乙胺（PEA）和3-氟苯乙胺（m-F-PEA）]的二维钙钛矿薄膜/C异质结构，系统地研究了载流子扩散和界面转移过程。使用厚度约为7nm的二维钙钛矿薄膜，我们观察到二维钙钛矿与C层之间电子转移时间的细微差异，这可归因于有限的厚度和相似的电子耦合强度。然而，在厚度依赖性电荷转移研究中，随着二维钙钛矿厚度增加，由于与（PEA）PbI和（m-F-PEA）PbI相比，（BA）PbI的激子-声子相互作用更强，导致（BA）PbI的载流子扩散较差，（BA）PbI/C异质结构中的电子转移效率下降最为迅速。同时，随着钝化剂浓度增加，与PEAI和m-F-PEAI处理的二维/三维PSC相比，BAI处理的二维/三维PSC的填充因子下降最为迅速。这项研究表明，当使用具有刚性分子结构的钝化剂时，通过增加二维/三维PSC中钝化剂的浓度来提高开路电压并最小化填充因子的下降更容易。
