Carbazole-based conjugated polymer with tethered acetylene groups: Synthesis and characterization

A novel carbazole-based conjugated polymer with tethered acetylenes, poly [(9,9-dioctyl)-2,7-fluorene-(N-octyl-3,6-carbazole)]-co-[(9,9-dioctyl)-2,7-fluorene-(N-4-phenylacetylene)-3,6-carbazole)] (P-2), was successfully synthesized through the desilylation of triisopropylsilyl (TIPS) protected precursor polymer, poly [(9,9-dioctyl)-2,7-fluorene-(N-octyl-3,6-carbazole)]-co-[(9,9-dioctyl)-2,7-fluorene-(N-4-triisopropylsilyl-phenylacetylene)-3,6-carbazole)] (P-1). Thermally induced crosslinking between periphery acetylenes attached on P-2 began to occur when heating temperature above 220 °C, and the solubility of P-2 decreased significantly after curing. Nanodispersion of P-2 in water was readily prepared by reprecipitation protocol. Optical properties of P-2 in different states were characterized by UV–vis and photoluminescence analyses. Acceptable quantum efficiency (QE, 0.13) and binding ability with Hg2+ allow P-2's nanodispersion to act as optical probe for the detection of Hg2+ in aqueous phase. Primary investigation for the application of P-2 as hole-transport layer (HTL) in multilayer polymeric light-emitting devices (PLEDs) shown that the device with the insertion of P-2 between PEDOT:PSS and emissive layer affords better performance as compared to that of PEDOT:PSS-based one HTL device.

► A kind of conjugated carbazole-based polymer with tethered acetylenes was prepared. ► Corresponding polymer nanoparticle in aqueous phase was prepared. ► This nanodispersion can be used as Hg2+ optical probe in pure water phase. ► This polymer can also act as crosslinkable hole-transport layer in PLEDs.