am0c02295_si_001.pdf (3.92 MB)
Download fileHighly Efficient and Stable Pure Two-Dimensional Perovskite-Based Solar Cells with the 3‑Aminopropionitrile Organic Cation
journal contribution
posted on 2020-04-08, 14:18 authored by Yaru Li, Yang Zhao, Haoliang Cheng, Ke Zhao, Zhong-Sheng WangPure
two-dimensional (2D) perovskite (n = 1)-based
perovskite solar cells (PSCs) have been proven to have excellent stability
against humidity, but the photovoltaic performance is very poor due
to the parallel orientation to the substrate and mismatched energy
alignment in the PSC device. We report herein a novel bulky organic
cation of 3-aminopropionitrile (3-APN) for constructing a pure 2D
hybrid lead–iodide perovskite. The crystal structure of (3-APN)2PbI4 features a stable layered and undistorted
PbI6 octahedral geometry (∠Pb–I–Pb
= 180°) with a small I···I distance (4.66 Å),
and the crystals grow in a dominant out-of-plane direction to the
substrate. In addition, the existence of an intramolecular H bond
between cyano groups and ammonium heads result in an appropriate valence
band level of (3-APN)2PbI4 for a well-matched
energy level alignment in the device, benefitting the interfacial
charge transfer and hence a better photovoltaic performance. As a
result, the PSC with the pure 2D (3-APN)2PbI4 perovskite-based PSC achieves a power conversion efficiency of 3.39%,
which is the highest value thus far for the pure 2D lead–iodide
perovskite family, to the best of our knowledge. More importantly,
this pure 2D (3-APN)2PbI4 perovskite-based PSC
demonstrates excellent stability against humidity. This work demonstrates
that there is great potential to realize efficient and stable pure
2D perovskite-based PSCs through the wise design of organic cations.