Electric-field-induced deposition of rubrene: preparation of aqueous colloidal suspensions with ionic surfactant and exploration of deposition conditions

Deposition of large-area rubrene film in a cost- and environment-friendly manner without vacuum deposition is essential for the deployment of photon upconversion sheets based on rubrene via triplet-triplet annihilation. In this study, the electric-field-induced deposition of rubrene from aqueous suspensions stabilized by anionic (sodium dodecyl sulfate [SDS]) or cationic (dodecyltrimethylammonium bromide [DTAB]) surfactants has been successfully demonstrated. A systematic exploration of the deposition conditions revealed that the voltage required for uniform deposition of colloidal particles over the electrode is much higher than triggering water electrolysis, suggesting that the electric-field-assisted deposition achieved is not simple electrophoretic deposition but is strongly influenced by water electrolysis.