Dimeric perylene-bisimide organic molecules: application as a quantum battery

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 (ν ₁ = ν ₂) suppresses both ergotropy and charging power due to symmetric thermal population distributions. Introducing finite detuning (Δ = ν ₁ − ν 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.