Multicolor Photoluminescence of a Hybrid Film via the Dual-Emitting Strategy of an Inorganic Fluorescent Au Nanocluster and an Organic Room-Temperature Phosphorescent Copolymer

Achieving multicolor photoluminescence, especially white-light emission, under mild conditions based on hybrid organic-inorganic materials has attracted growing attention. A novel system, via a histidine modified Au nanocluster (AuNC@histidine) with bluish green fluorescence and a 4-bromo-1,8-naphthalic anhydride derivative polymer (poly-BrNpA) with orange room-temperature phosphorescence (RTP) emission, was designed and prepared. White light emission could be achieved by adjusting the proportions of the two components. The hydrogen bond enhanced the RTP emission of such copolymer systems through suppressing the nonradiative relaxation process by the well-formed and highly cross-linked network. By introducing fluorescence compounds (AuNC@histidine) which were insensitive to environmental humidity, this fluorescence-phosphorescence dual emitting hybrid system could also be used as a humidity responsive material, since the hydrogen bonds in poly-BrNpA chains could be broken by environmental humidity. The color switching could be well conducted in a poly(vinyl alcohol) (PVA) matrix, which was good for forming a processable and humidity responsive film.