Exploring Electronic Structure and Order in Polymers via Single-Particle Microresonator Spectroscopy

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is a crucial transparent conductive polymer for electronic applications.
• Understanding the complex interplay between electronic and morphological properties in PEDOT:PSS is hindered by its inherent structural heterogeneity.
• Existing research often overlooks nanoscale variations, limiting a comprehensive understanding of its behavior.

Purpose of the Study:

• To investigate the electronic structure and morphology of PEDOT:PSS at the single-particle level.
• To elucidate the relationship between nanoscale morphology and macroscopic electronic properties.
• To provide a bottom-up perspective on PEDOT:PSS behavior, from individual polymers to thin films.

Main Methods:

• Employed an optical microresonator-based absorption spectrometer for single-particle measurements.
• Utilized complementary theoretical calculations and ultrafast spectroscopy.
• Examined electronic structure and morphology across various length scales, from single polymers to nascent films.

Main Results:

• Demonstrated that individual PEDOT:PSS polymers exhibit bulk-like optical responses.
• Identified highly ordered PEDOT assemblies with long-range ordering facilitated by the PSS matrix.
• Observed a preferential surface orientation of PEDOT nanocrystallites in single particles, differing from bulk films.

Conclusions:

• A single-particle perspective offers unique insights into the microscopic structure and electronic properties of PEDOT:PSS.
• The PSS matrix plays a critical role in mediating the ordering of PEDOT assemblies.
• The observed surface orientation has significant implications for interfacial electronic communication in PEDOT:PSS-based devices.