Quantum modelling of hydroxyl topology control of the Stokes-induced stark effect in hybrid flavonoid–semiconductor interfaces

The Stokes-Induced Stark Effect (SISE) has recently been identified as a novel mechanism for generating localized electric fields at hybrid photoactivated molecular–semiconductor interfaces, yet the structural factors governing its magnitude remain unresolved. Here, we develop a quantum-mechanical framework demonstrating that the strength of SISE is quantitatively controlled by the hydroxyl topology of flavonoid chromophores through excited-state intramolecular proton transfer (ESIPT). ESIPT induces transient charge redistribution and dipole amplification, which act as the primary source of the interfacial electric field. Using a Rosen–Morse II potential, the framework provides a dual-regime description of the interface, comprising a global bound-state formulation and a local Airy-type reduction for strong-field behavior. A hydroxyl-topology descriptor Ω_OH, constructed from excited-state dipole change, molecular orientation, and interfacial separation, is introduced to capture the ESIPT-mediated structural dependence and is applied to a series of flavonoids (myricetin, quercetin, kaempferol, luteolin, and curcumin). The results show that SISE-induced energy shifts follow distinct scaling laws, with ΔE_n∝Ω_OH^2in the global regime and E_n∝Ω_OH^(2/3)in the local regime, accompanied by a transition from symmetric confinement to field-driven localization. The analysis further identifies the B-ring pyrogallol configuration as the optimal architecture for maximizing SISE, while ESIPT-inactive systems define a limiting case with suppressed field generation. This work establishes the first quantitative structure–field relationship for SISE, providing a predictive basis for the molecular design of field-tunable hybrid optoelectronic interfaces.