All ink-jet printed polyfluorene photosensor for high illuminance detection

Abstract

An all-printed photosensor based on polyfluorene derivatives has been developed for high illuminance range detection (>100 klux). The active layer is a blend of hole-accepting poly(9,9′-dioctylfluorene-co-bis- N, N′-(4-butylphenyl)-bis- N, N′-phenyl-1,4-phenylenediamine) (PFB) and electron-accepting poly(9,9′-dioctylfluorene-co-benzothiadiazole) (F8BT). A top-absorbing architecture was used with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent electrode. The surface energy of the PEDOT:PSS ink was modified in order to allow printing directly onto the hydrophobic surface of the PFB:F8BT blend layer, placing the transparent electrode at the top of the light sensor structure. The all-printed photosensor shows a linear response over multiple measurements within the illuminance range of (100–400) klux.