Affiliation:
1. Robert Frederick Smith School of Chemical and Biomolecular Engineering Cornell University Ithaca NY 14853 USA
2. Centre for Functional Nanomaterials Brookhaven National Laboratory Upton NY 11973‐5000 USA
Abstract
Abstract2D‐on‐3D (2D/3D) perovskite heterostructures present a promising strategy to realize efficient and stable photovoltaics. However, their applicability in inverted solar cells is limited due to the quantum confinement of the 2D‐layer and solvent incompatibilities that disrupt the underlying 3D layer, hampering electron transport at the 2D/3D interface. Herein, solvent‐dependent formation dynamics and structural evolution of 2D/3D heterostructures are investigated via in situ X‐ray scattering. It is revealed that solvent interaction with the 3D surface determines the formation sequence and spatial distribution of quasi‐2D phases with n = 2–4. Isopropanol (IPA) reconstructs the perovskite into a PbI2‐rich surface, forming a strata with smaller n first, followed by a thinner substratum of larger n. In contrast, 2,2,2‐Trifluoroethanol (TFE) preserves the 3D surface, promoting the formation of uniformly distributed larger n domains first, and smaller n last. Leveraging these insights, Dion–Jacobson perovskites are used with superior charge transport properties and structural robustness to fabricate 2D/3D heterostructures dominated by n ≥ 3 and engineer a favorable energy landscape for electron tunneling. Inverted solar cells based on 3‐Aminomethylpyridine and TFE achieve a champion efficiency of 23.60%, with Voc and FF of 1.19 V and 84.5%, respectively, and superior stabilities with t94 of 960 h under thermal stress.
Funder
National Science Foundation
Subject
General Materials Science,Renewable Energy, Sustainability and the Environment