Suppression of dynamic disorder by electrostatic interactions in structurally close organic semiconductors

Area of Science:

• Materials Science
• Organic Electronics
• Solid-State Physics

Background:

• Dynamic disorder, arising from fluctuating charge transfer integrals, impedes charge transport in high-mobility organic semiconductors.
• Developing strategies to suppress dynamic disorder is crucial for advancing organic semiconductor technology.

Purpose of the Study:

• To investigate tuning molecular electrostatic potential as a novel strategy for suppressing dynamic disorder in organic semiconductors.
• To correlate molecular electrostatic interactions with crystal rigidity and charge transport properties.

Main Methods:

• Analysis of low-frequency (LF) Raman spectra for crystalline organic semiconductors: benzothieno[3,2-b][1]benzothiophene (BTBT), chrysene, tetrathienoacene (TTA), and naphtho[1,2-b:5,6-b']dithiophene (NDT).
• Correlation of spectral intensity differences with molecular electrostatic interactions and dynamic disorder levels.

Main Results:

• Significant variations in LF Raman spectra intensities were observed among the studied π-isoelectronic molecules.
• Chrysene and NDT exhibited suppressed dynamic disorder due to stronger intermolecular electrostatic interactions.
• A direct link between molecular electrostatic interactions, crystal rigidity, and reduced dynamic disorder was established.

Conclusions:

• Tuning molecular electrostatic potential is an effective strategy to suppress dynamic disorder in organic semiconductors.
• Stronger intermolecular electrostatic interactions enhance crystal rigidity, leading to improved charge transport.
• Guidelines for rational design of high-mobility organic semiconductors by increasing crystal rigidity are proposed.