• 제목/요약/키워드: polyfluorene

검색결과 23건 처리시간 0.024초

청색 발광 하이퍼브랜치 PF의 합성과 특성 분석에 관한 연구 (Synthesis and Characterization of Blue Light-Emitting Hyperbranched Poly(Fluorene))

  • 안택
    • 한국전기전자재료학회논문지
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    • 제23권9호
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    • pp.701-707
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    • 2010
  • We have synthesized new pure blue-emitting hyperbranched polyfluorene (Hyper-PDHF) through $A_2$ and $B_3$ type monomers via Suzuki coupling polymerization. The weight-average molecular weights ($M_w$) of the Hyper-PDHF was found about 35,000 with polydispersity index as 6.1. The UV absorption peak of the Hyper-PDHF film was at around 335 nm which was far blue shifted than that of linear PDHF film which was found at 380 nm. The pure blue photoluminescene (PL) peak of the Hyper-PDHF was measured at 419 nm as main emission with 397 and 444 nm as shoulder peaks. The Hyper-PDHF showed also higher PL quantum efficiency in solution than linear PDHF (Hyper-PDHF, $\Phi$sol =0.81; PDHF, $\Phi$sol=0.78). The annealed PDHF film (5 hrs on hot plate at $80^{\circ}C$) showed increased shoulder peak emissions and emission color was changed into the green emission. But, Hyper-PDHF film shows almost no excimer emission peak even the film was annealed. The enhanced PL efficiency and no excimer emission of Hyper-PDHF results from the inhibition of excimer formation by the introduction of the hyperbranched system into the polyfluorene backbone.

A Streak Camera Study of Amplified Spontaneous Emission in Polyfluorene Thin Film

  • Shin, Hee-Won;Kim, Yong-Rok
    • Rapid Communication in Photoscience
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    • 제4권4호
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    • pp.76-78
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    • 2015
  • We report on the photoluminescence (PL) properties of poly[2,7-(9-9-dioctylfluorene)] (PF) thin film under strong optical pumping using a streak camera system. When the excitation energy density increases above $72{\mu}J{\cdot}cm^{-2}$, the emission spectrum becomes narrower and PL decay curve comes to be faster simultaneously. These behaviors are clear evidence of Amplified Spontaneous Emission (ASE) due to a waveguided Stimulated Emission in slab structure of thin film. ASE threshold of $72{\mu}J{\cdot}cm^{-2}$ is comparable with previous reports and PF is attractive as a gain medium for plastic lasers.

High resolution patterning of polyfluorene derivative containing photo cross-linkable oxetane units

  • Park, Moo-Jin;Lee, Jeong-Ik;Chu, Hye-Yong;Kim, Seong-Hyun;Zyung, Taeh-Young;Hwang, Do-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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    • pp.1419-1420
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    • 2005
  • We have synthesized a photo patternable blue lightemitting polyfluorene (PF) derivative containing cross-linkable oxetane units. Poly(9,9-bis-(4-octyloxyphenyl)- fluorene-2,7-diyl-alt-9,9-bis-((3-hexyloxy-3'- ethyl)-oxetane)-fluorene-2,7-diyl) has been synthesized by Suzuki coupling polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope UV/visible spectroscopy, photoluminescence and scanning electron microscope (SEM). We obtained fine patterns with 10 mm resolution using the polymer film after exposure and development. This patterning method using conjugated polymers can be applicable to make fine pixels for PLEDs and OFETs.

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SiO2의 첨가를 통한 Polyfluorene계 Polymer-OLED의 발광 동작 개선 가능성 (Improved On-off Property of SiO2 Embedded Polyfluorene Polymer-OLED)

  • 전병주;김효준;김종수;정용석
    • 반도체디스플레이기술학회지
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    • 제16권1호
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    • pp.40-44
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    • 2017
  • The effect of weak dielectric silicone dioxide($SiO_2$) embedded in polyfluorene(PFO) emitting layer of polymer-based multi structure OLED was investigated. Indium tin oxide(ITO)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/poly(9,9-di-n-octylfluorenyl-2,7-diyl)(PFO)/2,2,2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)/aluminum(Al) structure OLED was fabricated by spin-coating method. Applied electric field causes some effect on $SiO_2$ in PFO layer. Thus, interaction between polymers and affected $SiO_2$ might generate electrical and luminance properties change. Experimental results, show the reduced threshold voltage of 6 V(from 23 V to 17 V). The maximum current density was rather increased from $71A/m^2$ to $610A/m^2$ and maximum brightness was also increased from $7.19cd/m^2$ to $41.03cd/m^2$, 9 and 6 times each. Additionally we obtained colour broadening result due to the increasing of blue-green band emission. Consequently we observed that electrical and luminance properties are enhanced by adding $SiO_2$ and identified the possibility of controlling the emission colour of OLED device according to colour broadening.

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고분자 전기 발광 다이오드(PLEDs)를 위한 포토리소그라피 패터닝 방법에 관한 연구 (The Investigation of Photolithographic Patterning Method for Polymer Light Emitting Diodes (PLEDs))

  • 김미경;이정익;김덕일;황치선;양용석;오지영;박상회;추혜용;김숙경;황도훈;이형종
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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    • pp.106-108
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    • 2004
  • We have investigated the photolithographic patterning method of light emitting polymer film for polymer light emitting diodes (PLED). Blue light emitting polymers based on polyfluorene, which can be cured photochemically to yield an insoluble form, have been synthesized using Ni(0) mediated Yamamoto polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope analysis, UV/visible spectroscopy, and photoluminescence. We have successfully fabricated PLEDs composed of the patterned emissive layer and their electroluminescence property has been also investigated. In this presentation, the detailed photolithographic patterning method and its application for polymer light emitting display will be discussed.

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Synthesis and Characterization of Iridium-Containing Green Phosphorescent Polymers for PLEDs

  • Xu, Fei;Kim, Hee Un;Mi, Dongbo;Lim, Jong Min;Hwang, Ju Hyun;Cho, Nam Sung;Lee, Jeong-Ik;Hwang, Do-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제34권2호
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    • pp.399-405
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    • 2013
  • Two series of new green phosphorescent polymers bearing a bis(2-phenyl-pyridine)iridium(III)(dibenzoylmethane) [$(ppy)_2Irdbm$] complex were designed and synthesized. Poly-carbazole (PCbz) derivative or polyfluorene with pendant carbazole groups (PFCbz) were employed as host polymers for the iridium complex. The iridium complex monomer was copolymerized with the host monomers using varying monomer ratios via a Yamamoto coupling reaction. Efficient energy transfer from host to dopant unit was observed by increasing the ratio of the iridium guest in the copolymers. Electroluminescent devices with the configuration ITO/PEDOT:PSS/polymer/BmPyPB/LiF/Al were fabricated and characterized. The phosphorescent polymers composed of the iridium complex guest and polyfluorene with carbazole pendants as a host performed better than the polymers composed of the same guest and the main chain polycarbazole host. A maximum external quantum efficiency of 0.73%, a luminous efficiency of 1.21 cd/A, and a maximum luminance of 372 $cd/m^2$ were obtained from a device fabricated using one of the synthesized copolymers.

Blue light-emitting polyalkylfluorene copolymers for LEDs

  • Hwang, Do-Hoon;Park, Moo-Jin;Kim, Suk-Kyung;Lee, Ji-Hoon;Lee, Chang-Hee;Kim, Yong-Bae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.874-876
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    • 2003
  • Blue light-emitting polyfluorene derivatives, poly[9,9-bis(4'-n-octyloxyphenyl) fluorene] (PBOPF), poly[9,9-bis(2'-ethylhexyl)]fluorene (PBEHF) and copolymers of PBOPF and PBEHF were synthesized through Ni(0) mediated polymerization and their light-emitting properties were investigated. The PBEHF thin film showed significant excimer band in PL spectra after thermal annealing at 100 $^{\circ}C$ for 2h. But no significant excimer emission was observed in the PL spectra of the PBOPF and the copolymers even after thermal annealing suggesting that BOPF unit effectively suppressed the excimer emission.

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Stable blue light emitting polyfluorenes with good solution processibility

  • Hwang, Do-Hoon;Lee, Ji-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1057-1059
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    • 2003
  • New polyfluorene derivatives, poly[9,9-bis(4' n-octyloxyphenyl)] fluorene (PAPF-8) and poly[9,9-bis(4'-(2",7"-dimethylocyloxy)phenyl)] fluorene (PAPF-10) were synthesized from the monomers, 2,7-dibromo-9,9-bis[4' (2"-ethylhexyloxy)benzene] fluorene and 2,7-dibromo-9,9-bis[4' (2", 7"-dimethyloctyloxybenzene)] fluorene through the Ni(0) mediated polymerization. The copolymers were characterized using FT-IR spectroscopy, UV-vis spectroscopy, TGA, photoluminescence (PL) & electroluminescence (EL) spectroscopy, elementa analysis, and molecular weight studies. The synthesized POPF-8 and POPF-10 showed a pure blue emission without any spectral change upon thermal annealing and EL device operation.

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Synthesis and Characterization of Fluorescent Poly(aryl ether thiadiazole)s and Poly(aryl ether oxadiazole)s

  • Gyesang Yoo;Hong, Sung-Il;Hwang, Seung-Sang;Lee, Jaehwan
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 1998년도 가을 학술발표회논문집
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    • pp.25-28
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    • 1998
  • Since the first report on poly(p-phenylenevinylene), the electroluminescent properties of namy conjugated polymers such as poly(p-phenylenevinylene) (PPV), poythiophene (PT), poly(p-phenylene) (PPP), and polyfluorene (PF) have been investigated because of their potential for use in display technology However, in the application of polymer light-emitting diodes (PLEDs), there are yet three fundamental issues to be considered: (1) full color capability, (2) emission efficiency, (3) stability (lifetime). (omitted)

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New red light-emitting copolymer based on polyfluorene

  • Cho, Nam-Sung;Hwang, Do-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.721-723
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    • 2002
  • We report a new red light emitting fluorene-based copolymer, poly{9,9-bis(2'-ethylhexyl)fluorene-2,7-diyl-co-2, 5-bis(2-thienyl-1-cyanovinyl}-1-(2'-ethylhexyloxy)-4methoxybenzene-5",5'''-diyl} (PFTCVB). The synthesized copolymers showed the absorption maxima at about 380 nm and the absorption between 425 and 600 nm increased as the fraction of the thiophene-containing monomer (BTCVB) increased. In PL, the emission maxima of the copolymers were red-shifted as the fraction of BTCVB increased, despite the similar absorption characteristics were shown in the UV-visible spectra. The copolymer containing 15 mol% of BTCVB showed a maximum PL and EL emission at 620 and 630 nm.

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