Organic semiconductor materials for fabricating organic light emitting diodes (OLEDs) have attracted significant attention in the field of novel optical and optoelectronic devices. Particulation of OLEDs’ emitting materials in small-scale has been limited only to tris(8-hydroxyquinoline) aluminum (Alq3) that emits green-light. In this study, we attempted to fabricate, for the first time, red-light emitting nanoparticles of phosphorescent organic semiconductor of bis(1-phenylisoquinoline) (acetylacetonate) iridium (Ir(piq)2(acac)). Rectangular particles with length and thickness of ∼2 μm and ∼50 nm were fabricated with guidance of cetyltrimethylammonium bromide (CTAB) and micro-plates with length and thickness of ∼5 μm and ∼100 nm were fabricated by sodium dodecyl sulfate (SDS). By contrast, single-stranded DNA (ssDNA) induced nano-rods with dimension of ∼400 nm in length and 100 nm in thickness. Hence, the choice of guiding agents resulted in distinctive crystal characteristic so that the nanorods by ssDNAs showed UV absorption with a red-shift in metal-ligand charge transfer (MLCT) by 54 nm whereas the particles by surfactants did 35 nm compared to the dissolved precursor. Higher was the ssDNA-guided nanorods in relative phosphorescence of the intensity at 610 nm over that at 695 nm than the surfactant-guided particles. [Figure not available: see fulltext.].
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In particular, iridium organometallic complexes are considered goodphosphorescent materials猃?because of the spin-orbiteffect Ir(piq)?(acac), cetyl trimethylammonium bromide (CTAB), sodium caused by the heavy metal ion. Many studies have been dedicated dodecyl sulfate (SDS), tetrahydrofuran (THF), and chloroform to the fabrication of particles based on organic phosphors.猃?-球?( ? ? ? ? ) were purchased frdormichA. lOligonucleotides were Particle syntheses with small molecules for OLED emitting materi-synthesized by Bioneer. The ssDNA sequence was used: NH?-als have been reported.球?-球?Our group previously reported the 眅∁ATCCTTATCAATATTTAACAATAATCC - 甅∁? fabrication of Alq?microparticles assisted by fluorescence dye-The particles were fabricated by modification of a previ-labeled DNA and confirmed a change in the optical properties ously reported method.球?Commercially available Ir(piq)?(acac) powder ( 甁爃眀 mg) was dissolved in THF ( 琀 mL) to obtain a 猁眃? Acknowledgments: This work was supported by the NationalResearch mg·mL-?stock solution. The surfactant solutions were prepared Foundationof Korea(NRF,球爃猃礀R 猀A琀B 甃爃爃砃礃礃爀 and 球爃猃)礀Mb 甀y dDi 猀ssAo l?vi?ng?ss?DN?A?or?CTAB or SDS in deionized water. The and a Korea University Grant. concentrations of the ssDNA, CTAB, and SDS solutions were ?. 稀M , ?mM, ? . ? mM, respectively. The stock solution ( ? mL) of the precursor was injected into the surfactant solution with vigor-
© 2018, The Polymer Society of Korea and Springer Nature B.V.
- bis(1-phenylisoquinoline) (acetylacetonate) iridium (Ir(piq)(acac))
- organic semiconductors
- red-light emitting nanoparticles
ASJC Scopus subject areas
- Chemical Engineering(all)
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry