An alternating copolymer for a blue light-emitting diode

Kim, J. K.; Hong, Seunghun; Cho, H. N.; Kim, D. Y.; Kim, C. Y.

doi:10.1007/s002890050034

Cited by 30 publications

(10 citation statements)

References 17 publications

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“…3,6-Diformyl-9-(2-ethylhexyl)-carbazole (11). 3,6-Diformyl-9-(2-ethylhexyl)-carbazole was synthesized by the previous work …”

Section: Methodsmentioning

confidence: 99%

Highly Efficient Light-Emitting Polymers Composed of Both Hole and Electron Affinity Units in the Conjugated Main Chain

Song¹,

Jang²,

Shim³

et al. 1999

Macromolecules

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Two new fully conjugated alternating copolymers containing both carbazole and oxadiazole units were prepared through the Wittig condensation polymerization (carbazole units were linked with oxadiazole units by meta and para). The polymers with the para linkage (PPOX−CAR) and the meta linkage (PMOX−CAR) in the main chain were soluble in common organic solvents and thermally stable on heating (the weight loss was less than 5% on heating to about 400 °C under nitrogen atmosphere). The maximum photoluminescence and the electroluminescence wavelengths of PPOX−CAR and PMOX−CAR were varied from 495 nm in the greenish-blue emission region to 450 nm in the blue emission region depending on the kink structure. The turn-on voltages of PPOX-CAR and PMOX-CAR were 7.5 and 10.5 V, respectively, when the single-layer light-emitting diodes of Al/PPOX-CAR or PMOX-CAR/ITO glass were fabricated. The maximum brightness of the Al/PPOX-CAR/ITO single-layer device was 500 cd/m2 at 20 V.

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“…3,6-Diformyl-9-(2-ethylhexyl)-carbazole (11). 3,6-Diformyl-9-(2-ethylhexyl)-carbazole was synthesized by the previous work …”

Section: Methodsmentioning

confidence: 99%

Highly Efficient Light-Emitting Polymers Composed of Both Hole and Electron Affinity Units in the Conjugated Main Chain

Song¹,

Jang²,

Shim³

et al. 1999

Macromolecules

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“…Introducing m- phenylene in poly(9,9‘-di- n -hexylfluorenediylvinylene- alt -1,3-phenylenevinylene) and in PPV has been briefly reported in recent literature. Quantitative characterization of m- phenylene on the conjugation length, PL efficiency, and chain rigidity of fully π-conjugated PPVs has not been reported.…”

Section: Referencesmentioning

confidence: 99%

A Highly Luminescent Poly[(m-phenylenevinylene)-alt-(p-phenylenevinylene)] with Defined Conjugation Length and Improved Solubility

Pang¹,

Li²,

Hu³

et al. 1999

Macromolecules

116

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A derivative of poly[(m-phenylenevinylene)-alt-(p-phenylenevinylene)] ( 7) has been synthesized via the standard Wittig condensation to investigate the effects of m-phenylene on the physical properties of PPVs. The polymer synthesized has a molecular weight of about 20 000, corresponding to a number-average degree of polymerization of about 41. A model compound, 1,4-distyryl-2,5-dihexyloxybenzene (9), has also been synthesized to evaluate the effectiveness of π-conjugation interruption at m-phenylene. Comparison of photoabsorption and emission characteristics between 7 and 9 indicates that the presence of m-phenylene effectively interrupts the conjugation in PPV, allowing precise color control in the fully π-conjugated polymers. 1 H NMR is found to be a convenient tool to characterize the cis/trans-olefins in the polymer. The PL quantum yield of 7 is quite high in both solution and solid states (0.6-0.8), suggesting potential applications of the material in various electrooptical devices.

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“…First, carbazole (Aldrich) was mixed with bromine in a mixture of carbon bisulfide and pyridine solution to give 3,6-dibromocarbazole ( 1 ) in a 83% yield. Then the alkylation of the nitrogen atom of 3,6-dibromocarbazole in THF by NaH and 2-ethylhexyl bromide leads to 3,6-dibromo-9-ethylhexylcarbazole ( 2 ) in a 75% yield . Finally, 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9-ethylhexylcarbazole ( 3 ) is prepared from 3,6-dibromo-9-ethylhexylcarbazole upon reaction with n -BuLi and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in anhydrous THF.…”

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confidence: 99%