Hybrid perovskites with chiral organic molecules: an Ab initio study of physicochemical properties

Author(s)

Guilherme Kazuo Inui

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2024-04-12

Examining board members

Juarez Lopes Ferreira da Silva; Marilia Junqueira Caldas; Caio Costa Oliveira

• Advisor: Juarez Lopes Ferreira da Silva

Abstract

The incorporation of chiral molecules into hybrid perovskite-based materials has paved the way for tailoring the optoelectronic properties of these perovskites through chirality transfer to the inorganic framework. However, there remains a gap in understanding the atomic-scale interaction between chiral molecules and the chemical composition driving the physicochemical properties of these materials. In this study, we employ density functional theory to investigate the structural and electronic properties of chiral perovskites (R-/S-NEA)2BX4 (R-/S-NEA = R-/S-1-(1-Naphthyl)ethylammonium, where B = Ge, Sn, Pb, X = Cl, Br, I). We find that R- and S-enantiomers and 3D bulk and slab models of the RuddlesdenPopper structure exhibit minimal differences in lattice constants, local structural parameters, and electronic properties. However, different enantiomers lead to opposite orientations of octahedral tilting due to chirality transfer to the inorganic framework, a consequence of halide electronegativity substitution. This transfer is also evident in RashbaDresselhaus spin-orbit coupling effects on the electronic band structure. Additionally, we demonstrate that differences in band gap are primarily governed by the natural atomic energy levels of inorganic elements, while organic molecules play a crucial role in controlling ionic potential and electron affinity for systems with light atoms. Band gap values range from 1,91 eV to 3,77 eV, pointing to the potential for designing advanced optoelectronic materials. (AU)

• FAPESP's process: 22/06925-5 - Theoretical investigation of chiral molecules in the physicochemical properties of hybrid perovskites
• Grantee: Guilherme Kazuo Inui
• Support Opportunities: Scholarships in Brazil - Master