Pradhan Santanu, Stavrinadis Alexandros, Gupta Shuchi, Bi Yu, Di Stasio Francesco, Konstantatos Gerasimos
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels (Barcelona), Spain.
ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010, Barcelona, Spain.
Small. 2017 Jun;13(21). doi: 10.1002/smll.201700598. Epub 2017 Apr 12.
The power conversion efficiency of colloidal PbS-quantum-dot (QD)-based solar cells is significantly hampered by lower-than-expected open circuit voltage (V ). The V deficit is considerably higher in QD-based solar cells compared to other types of existing solar cells due to in-gap trap-induced bulk recombination of photogenerated carriers. Here, this study reports a ligand exchange procedure based on a mixture of zinc iodide and 3-mercaptopropyonic acid to reduce the V deficit without compromising the high current density. This layer-by-layer solid state ligand exchange treatment enhances the photovoltaic performance from 6.62 to 9.92% with a significant improvement in V from 0.58 to 0.66 V. This study further employs optoelectronic characterization, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy to understand the origin of V improvement. The mixed-ligand treatment reduces the sub-bandgap traps and significantly reduces bulk recombination in the devices.
基于胶体硫化铅量子点（QD）的太阳能电池的功率转换效率因开路电压（V ）低于预期而受到显著阻碍。由于带隙内陷阱诱导光生载流子的体相复合，基于量子点的太阳能电池中的V亏缺比其他类型的现有太阳能电池要高得多。在此，本研究报告了一种基于碘化锌和3-巯基丙酸混合物的配体交换程序，以在不影响高电流密度的情况下降低V亏缺。这种逐层固态配体交换处理将光伏性能从6.62%提高到9.92%，V从0.58 V显著提高到0.66 V。本研究进一步采用光电表征、X射线光电子能谱和光致发光光谱来理解V改善的起源。混合配体处理减少了子带隙陷阱，并显著减少了器件中的体相复合。
