Theory of covalent adsorbate frontier orbital energies on functionalized light-absorbing semiconductor surfaces

Par Conseil national de recherches du Canada

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DOI	Trouver le DOI : https://doi.org/10.1021/jz400601t
Auteur	Rechercher : Yu, Min; Rechercher : Doak, Peter; Rechercher : Tamblyn, Isaac; Rechercher : Neaton, Jeffrey B.
Format	Texte, Article
Sujet	density functional theory; energy level alignment; many-body perturbation theory; organic−semiconductor interface; surface polarization; thiophene-functionalized silicon (111)
Résumé	Functional hybrid interfaces between organic molecules and semiconductors are central to many emerging information and solar energy conversion technologies. Here we demonstrate a general, empirical parameter-free approach for computing and understanding frontier orbital energies – or redox levels – of a broad class of covalently bonded organic–semiconductor surfaces. We develop this framework in the context of specific density functional theory (DFT) and many-body perturbation theory calculations, within the GW approximation, of an exemplar interface, thiophene-functionalized silicon (111). Through detailed calculations taking into account structural and binding energetics of mixed-monolayers consisting of both covalently attached thiophene and hydrogen, chlorine, methyl, and other passivating groups, we quantify the impact of coverage, nonlocal polarization, and interface dipole effects on the alignment of the thiophene frontier orbital energies with the silicon band edges. For thiophene adsorbate frontier orbital energies, we observe significant corrections to standard DFT (∼1 eV), including large nonlocal electrostatic polarization effects (∼1.6 eV). Importantly, both results can be rationalized from knowledge of the electronic structure of the isolated thiophene molecule and silicon substrate systems. Silicon band edge energies are predicted to vary by more than 2.5 eV, while molecular orbital energies stay similar, with the different functional groups studied, suggesting the prospect of tuning energy alignment over a wide range for photoelectrochemistry and other applications.
Date de publication	2013-04-26
Maison d’édition	American Chemical Society
Dans	The Journal of Physical Chemistry Letters 4, nº 10 : 1701–1706.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
Numéro NPARC	23003159
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Identificateur de l’enregistrement	9e137be5-d524-43b9-9a46-a653d6d64004
Enregistrement créé	2018-05-03
Enregistrement modifié	2020-05-30

Date de modification :: 2024-07-17