Exploring the Steric Hindrance of Alkylammonium Cations in the Structural Reconfiguration of Quasi-2D Perovskite Materials Using a High-throughput Experimental Platform

Reduced-dimensional (2D or quasi-2D) perovskites have recently attracted considerable interest due to their superior long-term stability. The nature of the intercalating cations plays a key role in determining the physicochemical properties and stability of the quasi-2D perovskites. Here, the thermal stability of a series of 2D Ruddlesden-Popper (RP) perovskites is studied using seven types of intercalating cations with increasing linear carbon-chain length from ethylammonium (EA) to n-dodecylammonium (DA) through a high-throughput platform. The results show that long-chain cations in quasi-2D perovskite films lead to strong steric hindrance between adjacent perovskite domains, thus suppressing Ostwald ripening during the thermal-aging process. For short-chain cations, increased-dimensional phase redistribution during the aging period is observed, which can benefit a concomitant regeneration of the 3D/3D-like perovskite phases. The impact of steric hindrance on structural reconfiguration and the subsequent phase redistribution in quasi-2D perovskites are systematically characterized by UV-vis absorption spectra, photoluminescence spectra, and X-ray diffraction patterns. Due to the steric hindrance effect, an optimal chain length is found to maximize film stability by balancing the water/oxygen resistance and increased-dimensional phase redistribution. This work provides new insight into the thermal stability of quasi-2D perovskites.

Automated summary

This study investigates the thermal stability of a series of quasi-2D perovskites and finds that long-chain cations can suppress thermal aging by hindering lattice rearrangement. On the other hand, short-chain cations promote increased-dimensional phase redistribution, benefiting the regeneration of the perovskite phase. UV-vis absorption spectra, photoluminescence spectra, and X-ray diffraction patterns are used to characterize the impact of steric hindrance on structural reconfiguration and phase redistribution in quasi-2D perovskites. An optimal chain length is identified to maximize film stability by balancing water/oxygen resistance and increased-dimensional phase redistribution.