Chen Xiangtian, Pasanen Hannu P, Khan Ramsha, Tkachenko Nikolai V, Janáky Csaba, Samu Gergely Ferenc
Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary.
Photonic Compounds and Nanomaterials, Chemistry and Advanced Material Group, Tampere University, Tampere FI-33720, Finland.
J Phys Chem Lett. 2024 Feb 22;15(7):2057-2065. doi: 10.1021/acs.jpclett.3c03536. Epub 2024 Feb 15.
The kinetics of electron extraction at the electron transfer layer/perovskite interface strongly affects the efficiency of a perovskite solar cell. By combining transient absorption and time-resolved photoluminescence spectroscopy, the electron extraction process between FACsPb(IBr) and TiO single crystals with different orientations of (100), (110), and (111) were probed from subpicosecond to several hundred nanoseconds. It was revealed that the band alignment between the constituents influenced the relative electron extraction process. TiO(100) showed the fastest overall and hot electron transfer, owing to the largest conduction band and Fermi level offset compared to FACsPb(IBr). It was found that an early electron accumulation in these systems can have an influence on the following electron extraction on the several nanosecond time scale. Furthermore, the existence of a potential barrier at the TiO/perovskite interface was also revealed by performing excitation fluence-dependent measurements.
电子转移层/钙钛矿界面处的电子提取动力学强烈影响钙钛矿太阳能电池的效率。通过结合瞬态吸收光谱和时间分辨光致发光光谱,从亚皮秒到几百纳秒对具有(100)、(110)和(111)不同取向的FACsPb(IBr)与TiO单晶之间的电子提取过程进行了探测。结果表明,各组分之间的能带排列影响了相对电子提取过程。TiO(100)表现出最快的整体和热电子转移,这是因为与FACsPb(IBr)相比,其导带和费米能级偏移最大。研究发现,这些系统中早期的电子积累在几纳秒的时间尺度上会对后续的电子提取产生影响。此外,通过进行与激发通量相关的测量,还揭示了TiO/钙钛矿界面处存在势垒。