MXenes are a recent family of 2D materials with very interesting electronic properties for device applications. One very appealing feature is the wide range of work functions shown by these materials, depending on their composition and surface terminations, that can be exploited to adjust band alignments between different material layers. In this work, based on density functional theory calculations, how mixed terminations of F, OH, and/or O affect the work function of Ti3C2 MXene is analyzed in detail, covering the whole phase‐space of mixtures. The Ti3C2/CH3NH3PbI3 (MAPbI3) perovskite coupled system for solar cell applications is also analyzed. A strong nonlinear behavior is found when varying the relative concentrations of OH, O, and F terminations, with the strongest effect of the OH groups in lowering the work function, already at a relative amount of 25%. A surprising minimum work function is found for relative OH:O fraction of 75:25, explained in terms of the nonlinear electronic response in screening the surface dipoles.

Di Vito, A., Pecchia, A., Auf der Maur, M., Di Carlo, A. (2020). Nonlinear Work Function Tuning of Lead‐Halide Perovskites by MXenes with Mixed Terminations. ADVANCED FUNCTIONAL MATERIALS, 1909028 [10.1002/adfm.201909028].

Nonlinear Work Function Tuning of Lead‐Halide Perovskites by MXenes with Mixed Terminations

Di Vito, Alessia;Auf der Maur, Matthias;Di Carlo, Aldo
2020-01-01

Abstract

MXenes are a recent family of 2D materials with very interesting electronic properties for device applications. One very appealing feature is the wide range of work functions shown by these materials, depending on their composition and surface terminations, that can be exploited to adjust band alignments between different material layers. In this work, based on density functional theory calculations, how mixed terminations of F, OH, and/or O affect the work function of Ti3C2 MXene is analyzed in detail, covering the whole phase‐space of mixtures. The Ti3C2/CH3NH3PbI3 (MAPbI3) perovskite coupled system for solar cell applications is also analyzed. A strong nonlinear behavior is found when varying the relative concentrations of OH, O, and F terminations, with the strongest effect of the OH groups in lowering the work function, already at a relative amount of 25%. A surprising minimum work function is found for relative OH:O fraction of 75:25, explained in terms of the nonlinear electronic response in screening the surface dipoles.
2020
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore ING-INF/01 - ELETTRONICA
English
density functional theory calculations; MXenes; perovskite solar cells; perovskites; work function tuning
Di Vito, A., Pecchia, A., Auf der Maur, M., Di Carlo, A. (2020). Nonlinear Work Function Tuning of Lead‐Halide Perovskites by MXenes with Mixed Terminations. ADVANCED FUNCTIONAL MATERIALS, 1909028 [10.1002/adfm.201909028].
Di Vito, A; Pecchia, A; Auf der Maur, M; Di Carlo, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/229974
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