Project Aether-Q

Abstract Conventional room-temperature optoelectronic materials suffer from rapid thermal decoherence of excitonic states, typically on the 50–100 fs timescale, driven by inelastic scattering with high-frequency optical phonons. Drawing inspiration from the structured, non-Markovian spectral densities observed in the Fenna–Matthews–Olson (FMO) photosynthetic complex, we propose a materials-design strategy — Project Aether-Q — in which a soft polymer intercalant is used to reshape the phonon spectral density of a quasi-two-dimensional Ruddlesden–Popperperovskite superlattice. Within a second-order cumulant (lineshape-function) treatment driven by an engineered spectral density, we show that suppression of the high-frequency continuum, together with retention of a residual low-frequency resonance, produces a clear prolongation of the pure-dephasing envelope of the excitonic coherence at 298 K. Under the parameter set examined here the unprotected 1/e time is approximately 60 fs while the phonon-caged model yields approximately 210–220 fs — a relative improvement of roughly 3–4×. Absolute timescales remain sensitive to the overall system–bath coupling strength; the essential physical content of the result is the relative benefit arising from spectral-density engineering. The present work is theoretical and numerical. The quantitative predictions remain to be tested by ultrafast two-dimensional electronic spectroscopy. The accompanying simulation code is released to facilitate further refinement.