Generalization on Entropy-Ruled Charge and Energy Transport for Organic Solids and Biomolecular Aggregates

Area of Science:

• Physical Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Electronic transport in organic solids and biomolecular aggregates is influenced by thermal disorder and electric fields.
• Existing models often treat hopping and band transport separately, limiting a unified understanding.
• Quantifying the interplay between charge and energy transport in soft matter remains a challenge.

Purpose of the Study:

• To present a generalized, entropy-ruled mechanism for charge and energy transport in organic solids and biomolecular aggregates.
• To explore the nonsteady carrier energy flux principle for soft matter systems.
• To unify hopping and band transport mechanisms and provide quantitative relations.

Main Methods:

• Utilized a differential entropy (h) driven charge transport framework.
• Developed a nonsteady carrier energy flux principle.
• Formulated a unified approach connecting relaxation time, hopping rate, and effective mass.
• Applied an entropy-ruled Einstein model to bridge adiabatic band and non-adiabatic hopping transport.

Main Results:

• Entropy is identified as a key parameter to classify carrier dynamics as nonsteady or steady.
• Calculated a disorder drift time of 9.3 × 10⁻⁷ s for hole transport in a TPA molecular device, indicating nuclear dynamics-coupled charge transfer.
• Demonstrated that the entropy-ruled Einstein model connects adiabatic band and non-adiabatic hopping transport.
• Logarithmic current density analysis differentiates between trap-free diffusion and trap-assisted recombination in molecular devices.

Conclusions:

• The generalized entropy-ruled mechanism provides a unified framework for understanding charge and energy transport across diverse organic systems.
• Non-equilibrium transport is anticipated in nonsteady carrier dynamics, offering new avenues for molecular device characterization.
• The study establishes a theoretical foundation for predicting transport mechanisms based on fundamental physical parameters.