A new, pH dependent and water-soluble, conjugated oligomer (amino, trimethylammonium oligophenylene vinylene, ATAOPV) was synthesized with a quaternary ammonium salt and an aromatic amine at the two ends of a π-conjugated oligomer, thus creating a strong dipole across the molecule. A unique white light LED is successfully fabricated from a stimuli responsive organic molecule whose emission properties are dominated by the pH value of the solution through controlled intermolecular charge transfer.
†Electronic supplementary information (ESI) available: Text: experiments, characterization, devices fabrication. Figures: NMR, titration curve, estimation of p K a, single quantum mode fit, absorption/PL spectrum in pH 2/12, different orbitals for molecule A, half-occupied natural orbitals, PL spectra of ATAOPV at different concentrations under different pH, experimental and calculated absorption and emission. See DOI: 10.1039/c4sc01911c