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Abstract

This work introduces a unified theoretical framework for quantum batteries (QBs) constructed from thermally equilibrated arrays of dimeric perylene bisimide (PBI) molecules. These organic dimers, with chemically tunable transition energies and dipole-dipole interactions, constitute a scalable and practical platform for quantum energy storage. Using exact diagonalization of the Gibbs state supported by analytic and numerical resource-theoretic tools, we evaluate four performance metrics: ergotropy, instantaneous charging power, storage capacity, and quantum coherence. We find that exact resonance ($\nu_1 = \nu_2$) suppresses both ergotropy and charging power due to symmetric thermal population distributions. Introducing finite detuning ($\Delta = \nu_1 - \nu_2$) breaks this symmetry, redistributes populations, and significantly enhances extractable work, charging power, and storage capacity. Furthermore, while the capacity remains invariant under unitary dynamics, providing a useful reference bound, intermediate dipole-dipole coupling strengths ($V_{12}$) optimize the trade-off between ergotropy, coherence retention, and storage performance. Crucially, coherence-assisted energy storage persists up to experimentally relevant temperatures, underscoring the thermal resilience of PBI-based QBs. These results establish spectral detuning and dipole-dipole interaction tuning as essential design principles, positioning PBI dimers as a chemically realistic, experimentally accessible, and thermodynamically robust platform that bridges molecular engineering with quantum energy storage.