Wan Li, Zhang Wenxiao, Wu Yulei, Li Xiaodong, Song Changjian, He Ying, Zhang Wenjun, Fang Junfeng
Key Laboratory of Graphene Technologies and Applications of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Nanoscale. 2019 May 16;11(19):9281-9286. doi: 10.1039/c9nr03030a.
Nanostructures have proved to be advantageous in light harvesting, improving the power conversion efficiency (PCE) of photovoltaic devices. However, the reported light-harvesting nanostructures all require extra processing beyond that for device fabrication, with multiple steps for nano-patterned structures or plasmonic nano-particles. Here we synthesized a conjugated polymer PFPDI which could simply form a nanostructured film on perovskite by spin coating. PFPDI possesses a perylene diimide-based backbone and phosphite ester pendants, which makes it a robust electron-transporting material (ETM) in perovskite solar cells. Furthermore, the perovskite solar cells with PFPDI as the electron-transporting layer (ETL) exhibited a higher light-harvesting efficiency compared to the standard phenyl-C61-butyric acid methyl ester (PCBM) devices. The JSC of the PFPDI device was enhanced from 19.71 mA cm-2 to 23.43 mA cm-2. SEM images and reflectance spectra confirmed that the PFPDI formed ditch-like nanostructures on perovskite film and induced a better light-harvesting efficiency. Further research indicated that the interaction of P[double bond, length as m-dash]O with Pb was essential to the formation of the nanostructures of PFPDI on perovskite. Therefore, our work not only offers an efficient organic ETM, but also opens up new horizons for simply constructing nanostructures with light-harvesting ability in photovoltaic devices.
纳米结构已被证明在光捕获方面具有优势，可提高光伏器件的功率转换效率（PCE）。然而，报道的光捕获纳米结构都需要在器件制造之外进行额外的处理，对于纳米图案结构或等离子体纳米颗粒需要多个步骤。在这里，我们合成了一种共轭聚合物PFPDI，它可以通过旋涂在钙钛矿上简单地形成纳米结构薄膜。PFPDI具有基于苝二酰亚胺的主链和亚磷酸酯侧链，这使其成为钙钛矿太阳能电池中一种强大的电子传输材料（ETM）。此外，与标准的苯基-C61-丁酸甲酯（PCBM）器件相比，以PFPDI作为电子传输层（ETL）的钙钛矿太阳能电池表现出更高的光捕获效率。PFPDI器件的短路电流密度（JSC）从19.71 mA cm-2提高到了23.43 mA cm-2。扫描电子显微镜（SEM）图像和反射光谱证实，PFPDI在钙钛矿薄膜上形成了沟状纳米结构，并诱导了更好的光捕获效率。进一步的研究表明，P=O与Pb的相互作用对于PFPDI在钙钛矿上形成纳米结构至关重要。因此，我们的工作不仅提供了一种高效的有机ETM，而且为在光伏器件中简单构建具有光捕获能力的纳米结构开辟了新的视野。
