Blue electroluminescence from polyhedral oligomeric silsesquioxane containing spirobifluorene trimers

• A new POSS-based deep blue light-emitting nanoparticle was synthesized.
• A spirobifluorene trimer was attached to POSS as the blue fluorescent chromophore.
• The POSS derivative was completely soluble and formed a uniform thin film.
• The POSS derivative showed blue PL as well as EL with good color purity.

We synthesized and characterized a new polyhedral oligomeric silsesquioxane (POSS)-based deep blue light-emitting nanoparticle. A spirobifluorene trimer (SFL3) was used as the blue fluorescent chromophore. The allyl-functionalized SFL3 was introduced to octakis(dimethylsiloxy)silsesquioxane via hydrosilylation to afford POSS-SFL3. POSS-SFL3 was completely soluble in common organic solvents such as chloroform, tetrahydrofuran, and p-xylene, and formed a uniform thin film upon spin-coating. The UV–vis absorption and photoluminescence (PL) emission maxima of POSS-SFL3 were 356 and 425 nm, respectively. An electroluminescent (EL) device with configuration ITO/PEDOT:PSS(40 nm)/poly-TPD(50 nm)/POSS-SFL3 (30 nm)/TPBI (40 nm)/LiF (0.5 nm)/Al (100 nm) was fabricated and showed a stable deep-blue electroluminescence with an electroluminescence (EL) maximum at 431 nm and CIE chromaticity coordinates of (0.17, 0.10).

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