Intermolecular Interactions of A-Site Cations Modulate Stability of 2D Metal Halide Perovskites

Abstract

Controlling the chemical properties of A-site cations in 2D metal halide perovskites (MHPs) and in 2D/3D assemblies is key to stable and efficient optoelectronic devices. Here, we rationalize the chemical interactions of different classes of organic cations in 2D MHPs, which are responsible for material stability in 2D and 2D/3D heterojunctions. Our results emphasize potential enhancement in stability by hydrogen bonding within the organic framework, showing substantially stronger intermolecular interaction compared to aromatic π−π stacking and aliphatic chains. This observation may lead to the design of organic cations with enhanced intermolecular interactions for increased stability in MHP-based devices.

Supramolecular virtual crystal: a fast and accurate guideline for molecular passivation of perovskite materials

“…Furthermore, the intermolecular interaction of the passivating agent makes the difference to the whole binding energy, hence leading to stabilizing behavior of the adsorbed molecules on the HOIP surface. This feature has been partially addressed in layered quasi-2D perovskites 58,59 and is also evidenced by a similar charge density difference profile produced on the molecule–surface bonding region, as seen in Fig. S1 †.…”

Tuning charge carrier dynamics through spacer cation functionalization in layered halide perovskites: an ab initio quantum dynamics study

“…The stronger hydrogen bonding enhances the internal stability and improves the electronic properties of halide perovskites. 63,69,70 Overall, along with molecular interlayer packing, the dynamic coupling between inorganic and organic moieties also gets modified with the functionalization of the spacer cations. Several studies have reported the complex impact of spacers on the dynamic structure and optoelectronic properties, including charge carrier transport in layered halide perovskites.…”

Interlayer Charge Transport in 2D Lead Halide Perovskites from First Principles

“…From a theoretical perspective, vertical charge transport in 2D perovskites is still a relatively unexplored area. Several computational works have screened potential 2D perovskite candidates by estimating the carrier effective mass along the out-of-plane direction. , Other groups have investigated the chemical interactions between spacer cations and the inorganic layer in 2D perovskites using first-principles calculations. − The Rothlisberger group proposed a simple barrier model to quantify the interlayer tunneling probability of 2D perovskites . The insulating nature of the spacer cation is reflected by the rather small tunneling probability in the out-of-plane direction.…”