Researchers from Northwestern University, University of Toronto and KAUST have hypothesized that perovskitoids, with robust organic-inorganic networks enabled by edge- and face-sharing, could impede ion migration. This addresses the issue of the migration of cations between 2D and 3D layers which results in the disruption of octahedral networks that leads to degradation in performance over time
The scientists explored a set of perovskitoids of varying dimensionality, and found that cation migration within perovskitoid/perovskite heterostructures was suppressed compared to the 2D/3D perovskite case. Increasing the dimensionality of perovskitoids improves charge transport when they are interfaced with 3D perovskite surfaces – the result of enhanced octahedral connectivity and out-of-plane orientation.
The 2D perovskitoid (A6BfP)8Pb7I22 (A6BfP: N-aminohexyl-benz[f]-phthalimide) was said to provide efficient passivation of perovskite surfaces and enable uniform large-area perovskite films.
Devices based on perovskitoid/perovskite heterostructures achieved a certified quasi-steady-state power conversion efficiency of 24.6% for centimeter-area PSCs.
The team removed the fragile hole transport layers and showed stable operation of the underlying perovskitoid/perovskite heterostructure at 85°C for 1,250 hours for encapsulated large-area devices in an air ambient.
