TY - JOUR
AU - Thomas Gray
AU - Jun Nishida
AU - Samuel Johnson
AU - Markus Raschke
AB - Order, disorder, and domains affect many of the functional properties in self-assembled monolayers (SAMs). However, carrier transport, wettability, and chemical reactivity are often associated with collective effects, where conventional imaging techniques have limited sensitivity to the underlying intermolecular coupling. Here we demonstrate vibrational excitons as a molecular ruler of intermolecular wave function delocalization and nanodomain size in SAMs. In the model system of a 4-nitrothiophenol (4-NTP) SAM on gold, we resolve coupling-induced peak shifts of the nitro symmetric stretch mode with full spatio-spectral infrared scattering scanning near-field optical microscopy. From modeling of the underlying 2D Hamiltonian, we infer domain sizes and their distribution ranging from 3 to 12 nm across a field of view on the micrometer scale. This approach of vibrational exciton nanoimaging is generally applicable to study structural phases and domains in SAMs and other molecular interfaces.
BT - Nano Letters
DA - 2021-09
DO - 10.1021/acs.nanolett.1c01515
IS - 13
M3 - doi: 10.1021/acs.nanolett.1c01515
N1 - doi: 10.1021/acs.nanolett.1c01515
N2 - Order, disorder, and domains affect many of the functional properties in self-assembled monolayers (SAMs). However, carrier transport, wettability, and chemical reactivity are often associated with collective effects, where conventional imaging techniques have limited sensitivity to the underlying intermolecular coupling. Here we demonstrate vibrational excitons as a molecular ruler of intermolecular wave function delocalization and nanodomain size in SAMs. In the model system of a 4-nitrothiophenol (4-NTP) SAM on gold, we resolve coupling-induced peak shifts of the nitro symmetric stretch mode with full spatio-spectral infrared scattering scanning near-field optical microscopy. From modeling of the underlying 2D Hamiltonian, we infer domain sizes and their distribution ranging from 3 to 12 nm across a field of view on the micrometer scale. This approach of vibrational exciton nanoimaging is generally applicable to study structural phases and domains in SAMs and other molecular interfaces.
PB - American Chemical Society
PY - 2021
SN - 1530-6984
SP - 5754
EP - 5759
T2 - Nano Letters
TI - 2D Vibrational Exciton Nanoimaging of Domain Formation in Self-Assembled Monolayers
UR - https://pubs.acs.org/doi/10.1021/acs.nanolett.1c01515
VL - 21
ER -