Molecular Engineering of Pure 2D Lead‐Iodide Perovskite Solar Absorbers Displaying Reduced Band Gaps and Dielectric Confinement
Abstract
Pure 2D lead‐iodide perovskites typically demonstrate poor charge transport and compromised visible light absorption, relative to their 3D congeners. This hinders their potential use as solar absorbers. Herein, the systematic tuning of pyridinium‐based templating cations is reported to introduce intermolecular interactions that provide access to a series of new 2D lead‐iodide perovskites with reduced inter‐octahedral distortions (largest Pb‐(μ‐I)‐Pb bond angles of 170–179°) and very short inorganic interlayer separations (shortest I⋅⋅⋅I contacts ≤4.278–4.447 Å). These features manifest in reduced band gaps (2.35–2.46 eV) and relaxed dielectric confinement (excitonic binding energies of 130–200 meV). As a consequence, they demonstrate (more than ten‐fold) improved photo‐ and electrical conductivities relative to conventional 2D lead‐iodide perovskites, such as that templated by 2‐(1‐naphthyl)ethylammonium. Through computational studies, the origin of this behavior was shown to derive from a combination of short iodoplumbate layer separations and the aromaticity of the organic dications.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 06, 2020
- Source ID
- 10.1002/cssc.202000028
Entities
People
- Benny Febriansyah
- Biplab Ghosh
- Jason England
- Nripan Mathews
- Padinhare Cholakkal Harikesh
- Teck Ming Koh
- Yongxin Li
- Yulia Lekina
- Zexiang Shen
Organizations
- Nanyang Technological University
- National Research Foundation
- Office of Naval Research Global