Thermally stable red electroluminescent hybrid polymers derived from functionalized silsesquioxane and 4,7‐bis(3‐ethylhexyl‐2‐thienyl)‐2,1,3‐benzothiadiazole

Abstract

Hyperbranched organic–inorganic hybrid conjugated polymers P1 and P2 were prepared via FeCl3‐oxiditive polymerization of 4,7‐bis(3‐ethylhexyl‐2‐thienyl)‐2,1,3‐benzothiadiazole (A) and octa(3‐ethylhexyl‐2‐thienyl‐phenyl)polyhedral oligomeric silsesquioxane (POSS) (B) at different POSS concentrations. Compared to linear polymer PM derived from A, P1, and P2 exhibit much higher PL quantum efficiency (ϕPL‐f) in condensed state with improved thermal stability. ϕPL‐f of P1 and P2 increased by 80% and 400%, and the thermal degradation temperatures of P1 and P2 are increased by 35 °C and 46 °C, respectively. Light‐emitting diodes were fabricated using P1, P2, and PM. While the electroluminescent spectra of both P1 and PM show λmax at 660 nm, P1 exhibits a much narrower EL spectrum and higher electroluminescence (∼500%) compared with PM at a same voltage and film thickness. The maximum current efficiency of P1 is more than seven times of that of PM. The turn‐on voltages of the LEDs are in the order of P2 > PM > P1. LED prepared by blending P1 with MEH‐PPV shows a maximum luminescence of 2.6 × 103 cd/m2 and a current efficiency of 1.40 cd/A, which are more than twice (1.1 × 103 cd/m2) and five times (0.27 cd/A) of LED of PM/MEH‐PPV blend, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5661–5670, 2009

Some recent developments of polyhedral oligomeric silsesquioxane (POSS)-based polymeric materials

“…Our extensive study on a series of starshaped oligophenylene and polythiophenes that are functionalized with POSS showed their significantly reduced aggregation and improved optical properties. 58,59 XRD and DSC studies showed that the incorporation of POSS greatly improves the processability of oligophenylene conjugated chains by transforming them from a crystalline state to a non-crystalline solid. For example, linear tetraphenyl derivative showed a crystallization peak at 114 C after a fast cooling process.…”

Synthesis and characterization of low bandgap conjugated donor–acceptor polymers for polymer:PCBM solar cells

“…Monomer 1 (TBT-0) and monomer 2 (TBT-in) were prepared according to the literature. 32,47 The other two monomers, monomer 3 and monomer 7 were prepared via a multistep synthesis (Scheme 2) and carefully purified before use. T8TBT-0 and T8TBT-in can be obtained by Suzuki-coupling (Pd(0) as catalyst) copolymerization of monomer 3 and monomer 1 (or 2).…”

“…Compound 1 and 2 were synthesized according to the literature. 32,47 The various chemicals were purchased from Fluka, Aldrich or Acros and used as received.…”

Star-branched cationic light-emitting dot with silsesquioxane core, synthesis, and light scattering studies

“…The sample was dried and a light yellow crystalline W was obtained (yield [ 90%) which is soluble only in water. 1 Characterization 1 H, 13 C, 29 Si nuclear magnetic resonance (NMR) data were obtained using a Bruker Avance 400 spectrometer. Elemental microanalysis was carried out by the Microanalysis Laboratory of the National University of Singapore.…”

“…The incorporation of the POSS with conjugated polymer provides a new approach to the preparation of organic light-emitting diodes with improved optoelectronic properties [9]. Recently, our group developed highly luminescent organic quantum dot clusters and polymers using POSS core [10][11][12][13][14]. The organic cluster composed of POSS and organic peripheries (conjugated chains) attached to the eight corners of the core.…”