• Title/Summary/Keyword: thickness enhancement

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Effect of Thermal Annealing on Nanoscale Thickness and Roughness Control of Gravure Printed Organic Light Emitting for OLED with PVK and $Ir(ppy)_3$

  • Lee, Hye-Mi;Kim, A-Ran;Kim, Dae-Kyoung;Cho, Sung-Min;Chae, Hee-Yeop
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1511-1514
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    • 2009
  • Organic light emitting layer in OLED device was formed by gravure printing process in this work. Organic surface coated by gravure printing typically showed relatively bad uniformity. Thickness and roughness control was characterized by applying various mixed solvents in this work. Poly (N-vinyl carbazole) (PVK) and fact-tris(2-phenylpyridine)iridium($Ir(ppy)_3$) are host dopant system materials. PVK was used as a host and Ir(ppy)3 as green-emitting dopant. To luminance efficiency of the plasma treatment on etched ITO glass and then PEDOT:PSS spin coated. The device layer structure of OLED devices is as follow Glass/ITO/PEDOT:PSS/PVK+Ir(ppy)3-Active layer /LiF/Al. It was printed by gravure printing technology for polymer light emitting diode (PLED). To control the thickness multi-printing technique was applied. As the number of the printing was increased the thickness enhancement was increased. To control the roughness of organic layer film, thermal annealing process was applied. The annealing temperature was varied from room temperature, $40^{\circ}C$, $80^{\circ}C$, to $120^{\circ}C$.

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Influence of PVP on the Thickness of Ferroelectric (Na,K)NbO3 Film by Sol-Gel (솔-젤 법을 통해 제조된 강유전체 (Na,K)NbO3 막의 두께에 미치는 PVP의 영향)

  • Kim, Dae-Gun;Yoo, In-Sang;Kim, Sae-Hoon;Kim, Jin-Ho
    • Korean Journal of Materials Research
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    • v.22 no.12
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    • pp.696-700
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    • 2012
  • (Na, K) $NbO_3$ thick film was successfully achieved using a sol-gel coating process with the addition of polyvinylpyrrolidone (PVP) to a metal alkoxide solution. The transparent coating solution, mixed with Nb:PVP = 1:1 in a molar ration, was synthesized by evaporating the solvent to over 62.5 wt%. Additive PVP increased the viscosity of the solution so that the coating thickness could be enhanced. The thickness of the (Na, K) $NbO_3$ film assisted by PVP was ca. 320 nm at the time of deposition; this value is four times thicker than that of the sample fabricated without PVP. Also, due to PVP binding with the OH groups of the metal alkoxide, the condensation reaction in the film was suppressed. The crystalline size of the (Na, K) $NbO_3$ films assisted by PVP was ca. 15 nm smaller than that of the film fabricated without PVP. After the sintering process at $700^{\circ}C$, the (Na, K) $NbO_3$ films were mainly composed of randomly oriented (Na, K) $NbO_3$ phase of perovskite crystal structure, including a somewhat secondary phase of $K_2Nb_4O_{11}$. However, by adding PVP, the content of the secondary phase became quite smaller than that of the sample without PVP. It was thought that the addition of PVP might have the effect of restraining the loss of potassium and that PVP could hold metalloxane by strong hydrogen bonding before complete decomposition. Therefore, the film thickness of the (Na, K) $NbO_3$ films could be considerably advanced and made more crack-free by the addition of PVP.