Cluster-Based Approach Utilizing Optimally Tuned TD-DFT to Calculate Absorption Spectra of Organic Semiconductor Thin...

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Chemistry

Background:

• Understanding organic semiconductor (OSC) photophysics is vital for material efficiency.
• Current methods like Frenkel-Holstein Hamiltonians and GW-Bethe-Salpeter calculations have limitations.
• Cluster-based quantum chemical methods offer potential but require refinement.

Purpose of the Study:

• To introduce an improved theoretical approach for simulating OSC thin films.
• To accurately reproduce experimental absorption spectra of representative OSC materials.
• To address drawbacks of existing cluster-based methods for OSC investigations.

Main Methods:

• Utilized an optimally tuned, range-separated time-dependent density functional theory (TD-DFT) approach.
• Employed clusters of multiple monomers combined with a polarizable continuum model.
• Simulated the thin-film environment for pentacene, tetracene, and perylene.

Main Results:

• Achieved excellent agreement (≤0.1 eV) between calculated and experimental absorption spectra.
• Demonstrated the accuracy of the TD-DFT protocol for OSC materials.
• Validated the combined cluster and continuum model approach for thin films.

Conclusions:

• The developed TD-DFT protocol enhances the accuracy of cluster-based approaches for OSCs.
• This method offers a parameter-independent and straightforward tool for OSC research.
• Chemical intuition can reduce computational cost while maintaining high accuracy in OSC studies.