IR Spectroscopy of Carboxylate-Passivated Semiconducting Nanocrystals: Simulation and Experiment

Fuente: arXiv
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Autores principales: Sowa, Jakub K., Cadena, Danielle M., Mehmood, Arshad, Levine, Benjamin G., Roberts, Sean T., Rossky, Peter J.
Formato: Preprint
Publicado: 2024
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author Sowa, Jakub K.
Cadena, Danielle M.
Mehmood, Arshad
Levine, Benjamin G.
Roberts, Sean T.
Rossky, Peter J.
author_facet Sowa, Jakub K.
Cadena, Danielle M.
Mehmood, Arshad
Levine, Benjamin G.
Roberts, Sean T.
Rossky, Peter J.
contents Surfaces of colloidal nanocrystals are frequently passivated with carboxylate ligands which exert significant effects on their optoelectronic properties and chemical stability. Experimentally, binding geometries of such ligands are typically investigated using vibrational spectroscopy, but the interpretation of the IR signal is usually not trivial. Here, using machine-learning (ML) algorithms trained on DFT data, we simulate an IR spectrum of a lead-rich PbS nanocrystal passivated with butyrate ligands. We obtain a good agreement with the experimental signal and demonstrate that the observed line shape stems from a very wide range of `tilted-bridge'-type geometries and does not indicate a coexistence of `bridging' and `chelating' binding modes as has been previously assumed. This work illustrates limitations of empirical spectrum assignment and demonstrates the effectiveness of ML-driven molecular dynamics simulations in reproducing IR spectra of nanoscopic systems.
format Preprint
id arxiv_https___arxiv_org_abs_2403_18779
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle IR Spectroscopy of Carboxylate-Passivated Semiconducting Nanocrystals: Simulation and Experiment
Sowa, Jakub K.
Cadena, Danielle M.
Mehmood, Arshad
Levine, Benjamin G.
Roberts, Sean T.
Rossky, Peter J.
Chemical Physics
Mesoscale and Nanoscale Physics
Materials Science
Surfaces of colloidal nanocrystals are frequently passivated with carboxylate ligands which exert significant effects on their optoelectronic properties and chemical stability. Experimentally, binding geometries of such ligands are typically investigated using vibrational spectroscopy, but the interpretation of the IR signal is usually not trivial. Here, using machine-learning (ML) algorithms trained on DFT data, we simulate an IR spectrum of a lead-rich PbS nanocrystal passivated with butyrate ligands. We obtain a good agreement with the experimental signal and demonstrate that the observed line shape stems from a very wide range of `tilted-bridge'-type geometries and does not indicate a coexistence of `bridging' and `chelating' binding modes as has been previously assumed. This work illustrates limitations of empirical spectrum assignment and demonstrates the effectiveness of ML-driven molecular dynamics simulations in reproducing IR spectra of nanoscopic systems.
title IR Spectroscopy of Carboxylate-Passivated Semiconducting Nanocrystals: Simulation and Experiment
topic Chemical Physics
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2403.18779