Geng Xinjian, Liu Yawen, Zou Xianshao, Johansson Erik M J, Sá Jacinto
Department of Chemistry-Ångstrom, Physical Chemistry, Uppsala University, 75120 Uppsala, Sweden.
Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland.
Phys Chem Chem Phys. 2023 Aug 30;25(34):22607-22613. doi: 10.1039/d3cp02190d.
Bromide-based perovskites have large bandgaps, making them attractive for tandem solar cells developed to overcome the Shockley-Queisser limit. A perovskite solar cell architecture employs transporting layers to improve charge extraction and transport. Due to the wide variety of materials and preparation methods, it is critical to devise fast screening methods to rank transporting layers. Herein, we evaluate perovskite fluorescence quenching followed by time- and energy-resolved photoluminescence (TER-PL) and analyse the intensity dependence as a potential method to qualify charge-transporting layers rapidly. The capability of the technique was evaluated with TiO/FAPbBr and SnO/FAPbBr, the most commonly used electron transporting layers, which were prepared using standard protocols to make best-performing devices. The results revealed that TiO is the most effective quencher due to the higher density of states in the conduction band, consistent with Marcus-Gerischer's theory. However, record-performance devices use SnO as the electron transport layer. This shows that the relationship between photoluminescence quenching and device performance is not bidirectional. Therefore, additional measurements like conductivity are also needed to provide reliable feedback for device performance.
基于溴化物的钙钛矿具有较大的带隙，这使得它们对于为克服肖克利-奎塞尔极限而开发的串联太阳能电池具有吸引力。钙钛矿太阳能电池结构采用传输层来改善电荷提取和传输。由于材料和制备方法种类繁多，设计快速筛选方法对传输层进行排名至关重要。在此，我们通过时间分辨和能量分辨光致发光（TER-PL）评估钙钛矿荧光猝灭，并分析强度依赖性，作为一种快速鉴定电荷传输层的潜在方法。使用最常用的电子传输层TiO/FAPbBr和SnO/FAPbBr对该技术的能力进行了评估，这些传输层是使用标准协议制备的，以制造性能最佳的器件。结果表明，由于导带中较高的态密度，TiO是最有效的猝灭剂，这与马库斯-格里舍尔理论一致。然而，创纪录性能的器件使用SnO作为电子传输层。这表明光致发光猝灭与器件性能之间的关系不是双向的。因此，还需要进行额外的测量，如电导率测量，以提供关于器件性能的可靠反馈。
