Molecular Engineering of Pure 2D Lead-Iodide Perovskite Solar Absorbers Displaying Reduced Band Gaps and Dielectric Confinement

Febriansyah, B., Lekina, Y., Ghosh, B. , Harikesh, P.C., Koh, T.M., Li, Y., Shen, Z., Mathews, N. and England, Jason (2020) Molecular Engineering of Pure 2D Lead-Iodide Perovskite Solar Absorbers Displaying Reduced Band Gaps and Dielectric Confinement. ChemSusChem, 13 (10). pp. 2693-2701. ISSN 1864-5631

Full content URL: https://doi.org/10.1002/cssc.202000028

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Molecular Engineering of Pure 2D Lead-Iodide Perovskite Solar Absorbers Displaying Reduced Band Gaps and Dielectric Confinement
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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.

Keywords:Binding energy, Energy gap, Image enhancement, Iodine compounds, Layered semiconductors, Light absorption, Perovskite, Solar absorbers, Computational studies, Dielectric confinement, Electrical conductivity, Inorganic interlayers, Intermolecular interactions, Molecular engineering, Octahedral distortion, Visible light absorption, Lead compounds
Subjects:F Physical Sciences > F200 Materials Science
F Physical Sciences > F120 Inorganic Chemistry
F Physical Sciences > F100 Chemistry
Divisions:College of Science > School of Chemistry
ID Code:51894
Deposited On:04 Oct 2022 09:00

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