Role of the Adsorption of Alkali Cations on Ultrathin $n$-Layers of Two-dimensional Perovskites

TL;DR

This study uses density functional theory to explore how alkali cations like Li, Na, K, Rb, and Cs interact with ultrathin 2D perovskite films, aiming to improve their stability for photovoltaic use.

Contribution

It provides new insights into the adsorption mechanisms of alkali cations on 2D perovskites, highlighting their potential for defect passivation and stability enhancement.

Findings

Alkali cations adsorb effectively on 2D perovskite surfaces.

Different cations show varying passivation efficiencies.

Adsorption improves thermodynamic stability of ultrathin films.

Abstract

Metal-halide semiconductors have great potential for real-life photovoltaic applications; however, surface defects induce several challenges to the thermodynamic stability. Here, we employed density functional theory calculations within van der Waals corrections (D3) to investigate the role of monovalent cations (Li, Na, K, Rb and Cs) in the passivation of 2D perovskite ultrathin films.