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Updated: May 20, 2026
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Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
Published on: June 23, 2023
Mapping Molecular/Nanocrystal Orientation with Nano-FTIR.
Tianyu Sheng1, Jianyu Ren1, Matthew R Espinosa2
1Department of Chemistry, University of California San Diego, La Jolla, California 92093, United States.
The Journal of Physical Chemistry Letters
|May 18, 2026
Summary
Researchers developed a new method to map molecular orientation in organic films at the nanoscale. This technique reveals sharp reorientations at grain boundaries, crucial for understanding material properties.
Area of Science:
- Materials Science
- Nanotechnology
- Spectroscopy
Background:
- Molecular orientation is key to organic thin film properties.
- Heterogeneous orientations and nanometer-scale domains are common.
- Conventional methods lack nanoscale spatial resolution for 3D orientation.
Purpose of the Study:
- To develop a quantitative method for resolving local molecular orientation.
- To achieve nanoscale spatial resolution in orientation characterization.
- To investigate molecular and nanocrystal organization in organic films.
Main Methods:
- Combining scattering-type scanning near-field optical microscopy (s-SNOM) with dipole reorientation mapping.
- Analyzing hyperspectral nano-FTIR data.
- Developing an experiment-to-simulation workflow using transition dipole moment (TDM) projections.
Main Results:
- Achieved ~40 nm spatial resolution for molecular orientation.
- Revealed uniform molecular alignment within domains.
- Observed sharp molecular reorientation at grain boundaries, invisible to topography.
- Determined nanocrystal orientation, showing ~55° tilt at grain boundaries.
Conclusions:
- The methodology provides a robust framework for decoding anisotropic organization.
- Applicable to organic semiconductors, catalytic surfaces, and biological assemblies.
- Overcomes limitations of diffraction-limited techniques for nanoscale characterization.
