Unveiling the role of chiral organic spacers on the structural, photophysical, and electronic properties of 2D and 2D/3D perovskite structures

Abstract

Metal halide perovskites (MHP), with the chemical formula ABX3 (A: monovalent organic or inorganic cation, B: divalent metal, and X: halide anion) have found application in a range of optoelectronic devices ranging from light-emitting diodes to solar cells, and photodetectors. The use of two-dimensional (2D) perovskite structures in these devices has been demonstrated to exhibit a number of advantages, including high environmental stability, suppressed ion migration, and improved chemical tunability as compared to the 3D analogs. In the 2D MHP, the inorganic network is separated by a large A-site cation, which provides an additional method to control the absorption and emission features, the quantum and dielectric confinements, as well as the crystal structure of the material. Also, 2D MHP is an interesting platform for investigating chirality transfer mechanisms. The use of an enantiomeric pure chiral organic cation will affect the structural, optical, and electronic properties, having promising applications in spintronics and non-linear optics. Compared to the racemic mixture, a pure enantiomer can result in a more ordered film, with all the metal-halide octahedrons tilted in the same direction. In this scenario, this proposal aims to elucidate how the use of a chiral molecule in the 2D MHP affects the charge carrier mobility of the material; this will be done by fabricating field-effect transistors with the chiral 2D MHP as the semiconducting active layer. Also, inverted p-i-n-type perovskite solar cells (PSC) using 3D/chiral-2D MHP heterostructures will be assembled to unveil if the presence of a more ordered structure could improve the efficiency of the device as well as its stability. These findings, accompanied by a detailed spectroscopic and microscopic characterization, will enable the understanding of fundamental aspects of the influence of chiral organic cation on the optical, electrical and structural properties of the MHP. (AU)