Primera Darwich Barbara, Guijarro Nestor, Cho Han-Hee, Yao Liang, Monnier Luc, Schouwink Pascal, Mensi Mounir, Yum Jun-Ho, Sivula Kevin
Laboratory for Molecular Engineering of Optoelectronic Nanomaterials, École Polytechnique Fédérale de Lausanne (EPFL), Station 6, 1015, Lausanne, Switzerland.
Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Rue de l'Industrie 17, 1951, Sion, Switzerland.
ChemSusChem. 2021 Jul 22;14(14):3001-3009. doi: 10.1002/cssc.202100992. Epub 2021 Jun 21.
Incorporating extended pi-conjugated organic cations in layered lead halide perovskites is a recent trend promising to merge the fields of organic semiconductors and lead halide perovskites. Herein, we integrate benzodithiophene (BDT) into Ruddlesden-Popper (RP) layered and quasi-layered lead iodide thin films (with methylammonium, MA) of the form (BDT) MA Pb I . The importance of tuning the ligand chemical structure is shown as an alkyl chain length of at least six carbon atoms is required to form a photoactive RP (n=1) phase. With N=20 or 100, as prepared in the precursor solution following the formula (BDT) MA Pb I , the performance and stability of devices surpassed those with phenylethylammonium (PEA). For N=100, the BDT cation gave a power conversion efficiency of up to 14.7 % vs. 13.7 % with PEA. Transient photocurrent, UV photoelectron spectroscopy, and Fourier transform infrared spectroscopy point to improved charge transport in the device active layer and additional electronic states close to the valence band, suggesting the formation of a Lewis adduct between the BDT and surface iodide vacancies.
将扩展的π共轭有机阳离子引入层状卤化铅钙钛矿中是一种近期的趋势，有望融合有机半导体和卤化铅钙钛矿领域。在此，我们将苯并二噻吩（BDT）整合到形式为(BDT)MA Pb I 的Ruddlesden-Popper（RP）层状和准层状碘化铅薄膜（含甲胺，MA）中。调整配体化学结构的重要性体现在形成光活性RP（n = 1）相需要至少六个碳原子的烷基链长度。按照(BDT)MA Pb I 的配方在前驱体溶液中制备，当N = 20或100时，器件的性能和稳定性超过了使用苯乙铵（PEA）的器件。对于N = 100，BDT阳离子的功率转换效率高达14.7%，而PEA为13.7%。瞬态光电流、紫外光电子能谱和傅里叶变换红外光谱表明器件有源层中的电荷传输得到改善，且在价带附近有额外的电子态，这表明BDT与表面碘化物空位之间形成了路易斯加合物。
