Saygili Yasemin, Turren-Cruz Silver-Hamill, Olthof Selina, Saes Bartholomeus Wilhelmus Henricus, Pehlivan Ilknur Bayrak, Saliba Michael, Meerholz Klaus, Edvinsson Tomas, Zakeeruddin Shaik M, Grätzel Michael, Correa-Baena Juan-Pablo, Hagfeldt Anders, Freitag Marina, Tress Wolfgang
Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
Benemérita Universidad Autónoma de Puebla., CIDS, Av. San Claudio y 18 Sur, Col. San Manuel, Ciudad Universitaria, CP 72570, P.O. Box 1067, Puebla, Pue., 7200, México.
Chemphyschem. 2018 Jun 5;19(11):1363-1370. doi: 10.1002/cphc.201800032. Epub 2018 Apr 26.
In perovskite solar cells (PSCs), the most commonly used hole transport material (HTM) is spiro-OMeTAD, which is typically doped by metalorganic complexes, for example, based on Co, to improve charge transport properties and thereby enhance the photovoltaic performance of the device. In this study, we report a new hemicage-structured iron complex, 1,3,5-tris(5'-methyl-2,2'-bipyridin-5-yl)ethylbenzene Fe(III)-tris(bis(trifluoromethylsulfonyl)imide), as a p-type dopant for spiro-OMeTAD. The formal redox potential of this compound was measured as 1.29 V vs. the standard hydrogen electrode, which is slightly (20 mV) more positive than that of the commercial cobalt dopant FK209. Photoelectron spectroscopy measurements confirm that the iron complex acts as an efficient p-dopant, as evidenced in an increase of the spiro-OMeTAD work function. When fabricating planar PSCs with the HTM spiro-OMeTAD doped by 5 mol % of the iron complex, a power conversion efficiency of 19.5 % (AM 1.5G, 100 mW cm ) is achieved, compared to 19.3 % for reference devices with FK209. Open circuit voltages exceeding 1.2 V at 1 sun and reaching 1.27 V at 3 suns indicate that recombination at the perovskite/HTM interface is low when employing this iron complex. This work contributes to recent endeavors to reduce recombination losses in perovskite solar cells.
在钙钛矿太阳能电池（PSC）中，最常用的空穴传输材料（HTM）是螺环-OMeTAD，它通常由金属有机配合物（例如基于钴的配合物）掺杂，以改善电荷传输性能，从而提高器件的光伏性能。在本研究中，我们报道了一种新型半笼状结构的铁配合物，即1,3,5-三（5'-甲基-2,2'-联吡啶-5-基）乙苯铁（III）-三（双（三氟甲基磺酰）亚胺），作为螺环-OMeTAD的p型掺杂剂。该化合物相对于标准氢电极的形式氧化还原电位经测量为1.29 V，比市售钴掺杂剂FK209的电位略正（20 mV）。光电子能谱测量证实该铁配合物可作为一种有效的p型掺杂剂，螺环-OMeTAD功函数的增加证明了这一点。当用5 mol％的铁配合物掺杂HTM螺环-OMeTAD制备平面PSC时，实现了19.5％（AM 1.5G，100 mW/cm²）的功率转换效率，而使用FK209的参考器件的功率转换效率为19.3％。在1个太阳光照下开路电压超过1.2 V，在3个太阳光照下达到1.27 V，这表明采用这种铁配合物时钙钛矿/HTM界面处的复合率较低。这项工作有助于近期为减少钙钛矿太阳能电池中的复合损失所做的努力。
