• Rapid Communication in Photoscience
• /
• 제4권3호
• /
• pp.70-72
• /
• 2015

Oligomers of p-phenylene vinylene and its derivatives have drawn much attention due to their unusual emission characteristics of showing increased emission when they form into nanoparticles. We have investigated the optical properties of the oligo-(p-phenylene vinylene) and its cyano-substituted derivatives in solution and in nanoaggregate media by femtosecond and picosecond time resolved fluorescence as well as stationary spectroscopies. All the spectroscopic data are consistent with the conclusion that the cyano substitution on the ${\beta}$-position of oligo-(p-phenylene vinylene) leads to breakage of the otherwise planar structure of cyano-unsubstituted molecules, which opens up an extremely efficient, as fast as 100 fs, non-radiative relaxation channel of the excited state. Formation of the nanoaggregates reverts the effect to make the molecules planar and to block the non-radiative relaxation channel. Therefore, concerning the applications in organic electroluminescent devices and organic light emitting diodes, substitution by the cyano group is not advantageous, although such modification should be useful in respect of controlling fluorescence intensity in different media.

• 대한화학회지
• /
• 제54권6호
• /
• pp.711-716
• /
• 2010

비닐렌기에 플루오르 치환기를 도입한 새로운 전자발광 (EL) 고분자인 poly(m-silylphenyl-p-phenylene-difluorovinylene) (m-SiP-PPDFV)는 GILCH polymerization 방법에 의해 합성된다. 이들 고분자는 단층 구조 (ITO/PEDOT/polymer/Ca:Al)의 light-emitting diodes (LEDs)에서 EL 발광층으로 사용되었다. m-SiP-PPDFV는 $\lambda_{max}$ = 452 nm 주위에서 PL 발광파장을 나타내었고, $\lambda_{max}$ = 497 nm 주위에서 녹색의 EL 발광을 나타내었다. 고분자의 current-voltage-luminance (I-V-L) 특성에서는 4.0 V 정도에서부터 소자가 작동되기 시작하였다. 고분자의 전자 친화도를 증가시키는 m-SiP-PPDFV을 얻기 위해 m-SiP-PPV의 모든 비닐렌기에 두개의 플루오르기를 도입하였고, 이로 인하여 소자 구동에서 비닐렌기의 색 안정도를 나타냈었다. PPV 유도체들에서 일어나는 비닐렌기의 산화반응을 보호하는 플루오르기는 전자 끄는 효과를 가지고 있어 소자의 색 안정도를 유지시킨다. 이번 연구로, 보다 안정화된 PPV 유도체를 얻기 위해, 플루오르기가 비닐렌기에 도입될 수 있음을 보여주고 있다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 추계학술대회 논문집
• /
• pp.367-367
• /
• 2007

Polymer/nanoparticle hybrids have been increasingly studied because of their enhanced properties for organic light emitting devices (OLEDs). In this study, we made poly(p-phenylene vinylene) (PPV) nanohybrid films by incorporation of Ag and $SiO_2$ nanoparticles into the PPV. A possible interaction between nanoparticles was investigated and especially we focused whether there is a change in the interaction between $SiO_2$ or Ag nanoparticles and matrix or not. The current characteristics of PPV nanohybrid films were analyzed by I-V and EL measurements. The optical properties were also investigated by UV-Vis spectroscopy and photoluminescence measurements.

• 한국세라믹학회:학술대회논문집
• /
• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
• /
• pp.50.2-50
• /
• 2003

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1997년도 춘계학술발표회 논문집
• /
• pp.37-41
• /
• 1997

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1996년도 추계 학술발표회
• /
• pp.460-464
• /
• 1996

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1997년도 추계총회 및 학술발표회 논문집
• /
• pp.19-22
• /
• 1997

• Macromolecular Research
• /
• 제15권2호
• /
• pp.142-146
• /
• 2007

Poly[(1-(9-carbazoly1)ethylene)-co-(3-cinnamoyloxyoctyl-9-carbazolyl)] ethylene (PVK-Cin) was prepared by tethering cinnamate pendants to a carbazole group via an octylene spacer. The photopatternability of the new PVK based-polymer was investigated using a photocrosslinking reaction under UV light illumination $(\lambda=254nm)$. Blends of the PVK-Cin and a soluble poly(phenylene vinylene) (CzEh-PPV) were employed to study the photocrosslinking behavior. Well resolved lithographic patterns were observed in these polymer systems. PVK-Cin produced a blue light emitting pattern both before and after the photocrosslinking reaction. The blends of PVK-Cin and CzEh-PPV also showed corresponding emissions at 398 and 525 (560) nm in the film state.

• Bulletin of the Korean Chemical Society
• /
• 제25권5호
• /
• pp.652-656
• /
• 2004

A new luminescent polymer, poly{1,4-phenylene-1,2-ethenediyl-2'-[2"-(4'"-octyloxyphenyl)-(5"-yl)-1",3",4"-oxadiazole]-1,4-phenylene-1,2-ethenediyl-2,5-bis-dodecyloxy-1,4-phenylene-1,2-ethenediyl} (Oxd-PPV), was synthesized by the Heck coupling reaction. Electron withdrawing pendant, conjugated 1,3,4-oxadiazole (Oxd), is on the vinylene unit. The band gap of the polymer figured out from the UV-visible spectrum was 2.23 eV and the polymer film shows bright yellow emission maximum at 552 nm. The electroluminescence (EL) maximum of double layer structured device (ITO/PEDOT:PSS/Oxd-PPV/Al) appeared at 553 nm. Relative PL quantum yield of Oxd-PPV film is 3.6 times higher than that of MEH-PPV film. The HOMO and LUMO energy levels of Oxd-PPV figured out from the cyclic voltammogram and the UV-visible spectrum are -5.32 and -3.09 eV, respectively, so that more balanced hole and electron injection efficiency can be expected compared to MEH-PPV. A double layer EL of Oxd-PPV has an maximum efficiency of 0.15 cd/A and maximum brightness of 464 cd/$m^2$.

• 센서학회지
• /
• 제6권4호
• /
• pp.252-257
• /
• 1997

ITO(indium-tin-oxide)/PPV(poly(p-phenylenevihylene))/음극 전극의 단층구조와 ITO /PVK(poly(N-vinylcarbazole))/PPV/음극전극의 이층구조를 가진 유기 EL(electroluminescence) 소자를 제작하였으며, 전기-광학적 특성을 측정하였다. 실험 결과, 단층구조에서는 PPV막의 열변환 온도를 $140^{\circ}C$에서 $260^{\circ}C$로 증가할수록 최대 휘도가 $118.8\;cd/m^{2}$(20V)에서 $21.14\;cd/m^{2}$(28V)으로 감소하였고, EL 스펙트럼의 최대 피크가 500nm에서 580nm로 이동하였다. 또한, 음극전극의 일함수가 낮을수록 소자의 발광휘도와 주입 전류는 증가되었다. 이층구조에서는 PVK막의 농도가 감소함에 따라 발광휘도가 $70.71\;cd/m^{2}$(32V)에서 $152.7\;cd/m^{2}$(26V)으로 증가하였다.