Quasi 2D perovskite solar cells (PSCs) are promising light absorbers that overcome the inherent instabilities of 3D perovskites. High-performance and stable 2D PSCs require careful control over the crystallographic orientation and phase distribution. This study introduces a simple and universal bifacial stamping method to obtain highly oriented perovskite crystals with a reverse-graded structure, where the low-n-value 2D perovskite phases are located mainly at the film surfaces. Bifacial stamping of 3D perovskite films atop the 2D films enables incorporation of 2D spacer cations into the 3D film surfaces, forming reverse-graded quasi-2D perovskite films. During stamping, suppressed evaporation of the precursor solvent induces heterogeneous nucleation from the contact interface between the 2D and 3D films, resulting in well-crystallized perovskite films having out-of-plane alignments with respect to the substrate. Thus, a highly oriented and reverse-graded quasi-2D perovskite with an average n value of 18 is obtained with power conversion efficiency exceeding 17% and high open-circuit voltage of 1.11 V for iso-butylammonium (iso-BA)-based (iso-BA2MAn−1PbnI3n+1) PSCs. The unencapsulated device retains 92% of its initial efficiency after aging at 40 ± 5% relative humidity for 1200 h. This work provides a new strategy for fabricating highly oriented and phase-controlled quasi-2D PSCs.
|Publication status||Published - 2022 Jul 21|
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation (NRF) of Korea grant (Nos. 2018M3D1A1058793, 2021R1A3B1068920, and 2021M3H4A1A03049662) funded by the Ministry of Science and ICT. This research was also supported by the Yonsei Signature Research Cluster Program of 2021 (2021‐22‐0002).
© 2022 Wiley-VCH GmbH.
All Science Journal Classification (ASJC) codes
- Materials Science(all)