Electron-phonon coupling in crystalline pentacene films.

Area of Science:

• Solid-state physics
• Materials science
• Surface science

Background:

• Electron-phonon (e-p) interactions are crucial for understanding the electronic properties of organic semiconductors.
• Pentacene (Pn) is a model organic semiconductor with potential applications in electronics.
• Understanding e-p coupling in pentacene films is essential for device optimization.

Purpose of the Study:

• To investigate the electron-phonon interaction in pentacene films grown on Bi(001).
• To quantify the e-p mass enhancement factor and effective Einstein energy.
• To determine the contribution of intermolecular vibrations to e-p effects and their impact on electronic bandwidth.

Main Methods:

• Photoemission spectroscopy was employed to study pentacene films.
• Analysis of spectral thermal broadening provided key parameters.
• Angle-resolved photoemission spectroscopy (ARPES) was used to probe electronic band structure.

Main Results:

• An e-p mass enhancement factor (lambda) of 0.36+/-0.05 was determined.
• An effective Einstein energy (omega{E}) of 11+/-4 meV was found, indicating dominant intermolecular vibration contributions.
• The highest occupied molecular orbital bandwidth narrowed by 15+/-8% between 75 and 300 K due to e-p coupling.

Conclusions:

• Intermolecular vibrations significantly contribute to e-p interactions in pentacene films.
• The observed e-p coupling effectively narrows the molecular orbital bandwidth, influencing charge transport.
• The findings provide quantitative insights into electron-phonon coupling in organic semiconductors.