White light emission from blue InGaN LED precoated with conjugated copolymer/quantum dots as hybrid phosphor

Hong Jeong Yu, Kwanhwi Park, Wonkeun Chung, Ji Hyun Kim, Sung Hyun Kim

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

In this work we fabricated white LEDs using a blue InGaN LED precoated conjugated copolymer/quantum dots (QDs) composite (green-emitting Poly {(9,9-dioctyl-2,7-divinylenefluorenylene)-alto-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)}/red-emitting CdSe quantum dots) as a hybrid phosphor. The emission peak wavelengths of the blue and red emissions in the spectra were 462 and 618 nm, respectively. The green-emitting polymer had two emission peaks at 515 and 543 nm. The subpeak of the copolymer (515 nm) was decreased by the absorption of QDs as the ratio of QDs increased, while the emission of the QD (618 nm) increased. Therefore, changes in the CIE-1931 coordinate, color temperature (Tc) and color-rendering index (Ra) were dependent on the QDs to copolymer ratios. The white LED of the hybrid phosphor containing 20 wt.% QDs had a luminous efficiency of 44.2 l m/W at 20 mA with a CIE-1931 coordinate, Tc and Ra of (0.3297, 0.3332), 5620 K and 75.3, respectively.

Original languageEnglish
Pages (from-to)2474-2477
Number of pages4
JournalSynthetic Metals
Volume159
Issue number23-24
DOIs
Publication statusPublished - 2009 Dec 1

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Keywords

  • Phosphors
  • Polyfluorene
  • Quantum dot
  • White light emitting diodes

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Condensed Matter Physics

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