The role of fullerene derivatives in perovskite solar cells: electron transporting or electron extraction layers?
The role of fullerene derivatives in perovskite solar cells: electron transporting or electron extraction layers?
复制标题
DOI：
10.1039/d0tc05903j
复制
发表时间：
2021-02-15
影响因子：
6.4
通讯作者：
Echegoyen, Luis
中科院分区：
文献类型：
--
作者：
Fernandez-Delgado, Olivia;Chandrasekhar, P. S.;Echegoyen, Luis
报道了具有不同碱度的伯、仲、叔氮原子富勒烯衍生物的合成、表征及其在钙钛矿太阳能电池中的应用。在这项工作中，我们测试的化合物作为传统的电子传输材料（ETM）在一个单一的层与苯基-C-61-丁酸甲酯（PC 61 BM）作为对照。此外，我们测试了将ETM分成两个不同层的想法：与钙钛矿界面处的薄电子提取层（EEL）和将电子传输到Ag电极的电子传输层（ETL）。本工作中的化合物也作为EEL进行测试，C-60作为顶部的ETL。我们的研究结果表明，新的富勒烯表现更好的EEL比ETM。使用BPy-C-60薄层（类似于3 nm）作为EEL的器件获得的最大功率转换效率（PCE）值为18.88%，高于仅使用纯C-60的对照器件（16.70%）的值。增加层厚度导致PCE值显著降低，清楚地证明该化合物是钙钛矿层的优秀电子提取器，但作为块状材料是差的传输器。通过稳态和时间分辨光致发光（SS-和TRPL）以及电化学阻抗谱（EIS）和X射线光电子能谱（XPS）测量证明了BPy-C-60衍生物的改进的钝化能力和电子提取能力;这可能归因于吡啶基团的碱性增强，这有助于与界面Pb 2+的更强相互作用。
The synthesis, characterization and incorporation of fullerene derivatives bearing primary, secondary and tertiary nitrogen atoms, which possess different basicities, in perovskite solar cells (PSCs), is reported. In this work, we tested the compounds as conventional electron transporting materials (ETMs) in a single layer with phenyl-C-61-butyric acid methyl ester (PC61BM) as control. Additionally, we tested the idea of separating the ETM into two different layers: a thin electron extracting layer (EEL) at the interface with the perovskite, and an electron transporting layer (ETL) to transport the electrons to the Ag electrode. The compounds in this work were also tested as EELs with C-60 as ETL on top. Our results show that the new fullerenes perform better as EELs than as ETMs. A maximum power conversion efficiency (PCE) value of 18.88% was obtained for a device where a thin layer (similar to 3 nm) of BPy-C-60 was used as EEL, a higher value than that of the control device (16.70%) with only pure C-60. Increasing the layer thicknesses led to dramatically decreased PCE values, clearly proving that the compound is an excellent electron extractor from the perovskite layer but a poor transporter as a bulk material. The improved passivation ability and electron extraction capabilities of the BPy-C-60 derivative were demonstrated by steady state and time-resolved photoluminescence (SS-and TRPL) as well as electrochemical impedance spectroscopy (EIS) and X-Ray photoelectron spectroscopy (XPS) measurements; likely attributed to the enhanced basicity of the pyridine groups that contributes to a stronger interaction with the interfacial Pb2+.