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This study introduces a parameter-free framework for predicting charge transport in molecular semiconductors by utilizing ab initio electron-phonon Hamiltonians to analyze carrier dynamics across extensive molecular domains. By employing nonperturbative Green-Kubo dynamics, the framework reveals emergent transport regimes and identifies the underlying mechanisms driving mobility in five representative crystal structures. Notably, the findings challenge the conventional understanding of DNTT's transport behavior, attributing its transient localization to correlated on-site disorder rather than independent hopping fluctuations, and suggest new design principles for high-mobility materials like picene.
The research overturns long-held assumptions about charge transport mechanisms in DNTT, revealing that acoustic phonons, not hopping fluctuations, are the key to understanding its mobility.
Charge transport governs organic transistors and photovoltaics, yet predicting it from atomic structure remains challenging. Electron--phonon interactions span disparate frequencies, strengths and spatial ranges, and collectively generate nonperturbative carrier dynamics. Existing methods regain tractability only by assuming a mechanism or reducing electron--phonon coupling to a few modes. We introduce a parameter-free framework that instead computes transport from ab initio electron--phonon Hamiltonians, propagating carriers across hundreds-of-molecule domains with the full phonon spectrum and letting transport regimes and bottlenecks emerge from nonperturbative Green--Kubo dynamics. Across five representative crystals, it captures measured mobilities, temperature exponents, and optical-conductivity fingerprints. Our results overturn the prevailing microscopic mechanism for DNTT, tracing its transient localization to correlated on-site disorder from acoustic phonons rather than independent hopping fluctuations. The resulting two-axis transport map provides design principles and highlights the underexplored phenacene family, exemplified by the high-mobility picene, as a promising direction.
