Electrofluorescence switching from a multilayer thin film by spin-assisted layer-by-layer assembly of an anionic fluorescent conjugated polyelectrolyte with poly(diallyldimethylammonium chloride)

An electrofluorochromic conjugated polyelectrolyte, PFTSO3Na as a polyanion, was synthesized and used in the fabrication of layer-by-layer (LbL) assembled multilayer film with poly(diallyldimethylammonium chloride) (PDDA) as a polycation. The electrofluorescent device (EFD) fabricated from the multilayer thin film of PFTSO3Na /PDDA emits blue light under UV excitation. The fluorescence intensity can be switched off upon electrochemical oxidation. The electrofluorescent behavior of the EFD is reversible and can be switched between the non-fluorescent (oxidized) state and the fluorescent (neutral) state with a maximum contrast ratio (If/If0) of 5.20.