• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.3 s.36
• /
• pp.213-217
• /
• 2005

The polymer light emitting diodes (PLED) with ITO/PEDOT:PSS/MEH-PPV/Al structure were prepared on ITO(indium tin oxide)/Glass substrates using PEDOT:PSS[poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] as the hole transport material and MEH-PPV[poly(2-methoxy-5-(2-ethyhexoxy)-1,4phenylenvinylene)] as emission material layer. The dependences on the surface roughnees and friction coefficient between film layers were investigated as a function of the MEH-PPV concentrations$(0.1\;wt\%\~0.9\;wt\%)$. The RMS values decreased from 1.72 nm to 1.00 nm as the concentration of MEH-PPV increased from $0.1\;wt\%\;to\;0.9\;wt\%$, indicating improvement of surface roughness. In addition, friction coefficients decreased from 0.048 to 0.035, which means the deteriorating of the adhesion condition. The PLED sample with $0.5\;wt\%$ of MEH-PPV showed the maximum luminance of $409\;cd/m^2$.

• Journal of Electrochemical Science and Technology
• /
• v.11 no.1
• /
• pp.50-59
• /
• 2020

Birnessite-type manganese dioxide (δ-MnO₂) with hierarchical micro-/mesoporosity was synthesized via sacrificial graphene template approach under mild hydrothermal conditions for the first time. Graphene template was obtained by a surfactant (cetyltrimethylammonium bromide, CTAB) assisted liquid phase exfoliation (LPE) in water. A thin PEDOT:PSS (poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate)) layer was applied to improve electrical conductivity and rate capability of MnO₂. The MnO₂ (535 F g^-1 at 1 A g^-1 and 45 F g^-1 at 10 A g^-1) and MnO₂/PEDOT:PSS nanocomposite (550 F g^-1 at 1 A g^-1 and 141 F g^-1 at 10 A g^-1) delivered electrochemical performances superior to their previously reported counterparts. An asymmetric supercapacitor, composed of MnO₂/PEDOT:PSS (positive) and Fe₃O₄/Carbon (negative) electrodes, provided a maximum specific energy of 18 Wh kg^-1 and a maximum specific power of 4.5 kW kg^-1 (ΔV= 2 V, 1M Na₂SO₄) with 85% capacitance retention after 1000 cycles. The graphene-templated MnO₂/PEDOT:PSS nanocomposite obtained by a simple and green approach promises for future energy storage applications with its remarkable capacitance, rate performance and cycling stability

• Korean Journal of Materials Research
• /
• v.33 no.7
• /
• pp.295-301
• /
• 2023

Thermoelectric (TE) energy harvesting, which converts available thermal resources into electrical energy, is attracting significant attention, as it facilitates wireless and self-powered electronics. Recently, as demand for portable/wearable electronic devices and sensors increases, organic-inorganic TE films with polymeric matrix are being studied to realize flexible thermoelectric energy harvesters (f-TEHs). Here, we developed flexible organic-inorganic TE films with p-type Bi_0.5Sb_1.5Te₃ powder and polymeric matrices such as poly(3,4-eethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly (vinylidene fluoride) (PVDF). The fabricated TE films with a PEDOT:PSS matrix and 1 wt% of multi-walled carbon nanotube (MWCNT) exhibited a power factor value of 3.96 µW·m^-1·K^-2 which is about 2.8 times higher than that of PVDF-based TE film. We also fabricated f-TEHs using both types of TE films and investigated the TE output performance. The f-TEH made of PEDOT:PSS-based TE films harvested the maximum load voltage of 3.4 mV, with a load current of 17.4 µA, and output power of 15.7 nW at a temperature difference of 25 K, whereas the f-TEH with PVDF-based TE films generated values of 0.6 mV, 3.3 µA, and 0.54 nW. This study will broaden the fields of the research on methods to improve TE efficiency and the development of flexible organic-inorganic TE films and f-TEH.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.301-301
• /
• 2013

전도성 고분자인 PEDOT은 PSS와 활용도를 높게 하기 위해 PSS와 함께 쓰이며, 다양한 분야에서 넓게 활용되고 있다. 하지만 박막 형성시 전도성이 작은 문제점이 있기 때문에 이를 개선할 필요성이 있다. 이에 본 연구에서는 용매를 사용한 PEDOT:PSS 박막의 처리 과정을 통하여 물성의 변화를 관찰하였으며, 전도성 향상을 관찰 하였다. 이를 위해 4-point probe장비를 이용하여 면저항을 측정하였으며, 동시에 Fe-SEM을 사용하여 박막의 무께를 알아 보았다. 또한 분자 수준의 관찰을 위해 Raman spectroscopy를 이용하였으며 동시에 FT-IR과 XPS장비를 사용하였다.

• Polymer(Korea)
• /
• v.33 no.5
• /
• pp.407-412
• /
• 2009

Vacuum deposited N,N-di-1-naphthyl-N,N-diphenyl-1,1'-biphenyl-4,4'-diamine (NPD) as a hole transporting (HTL) materials in OLEDs was placed on PEDOT-PSS, a hole injection layer (HIL). PEDOT-PSS was spin-coated on to the ITO glass. $C_{60}$-doped NPD-$C_{60}$(10 wt%) film was formed via co-evaporation process and the morphology of NPD-$C_{60}$ films was investigated using XRD and AFM. The J - V, L - V and current efficiency of multi -layered devices were characterized. According to XRD results, the deposited $C_{60}$ thin film was partially crystalline, but NPD-$C_{60}$ film was observed not to be crystalline, which indicates that $C_{60}$ molecules are uniformly dispersed in the NPD film. By using $C_{60}$-doped NPD-$C_{60}$ film as a HTL, the current density and luminance of multi-layered ITO/PEDOT-PSS/NPD-$C_{60}/Alq_3$/LiF/Al device were significantly increased by about 80% and its efficiency was improved by about 25% in this study.

• Journal of Sensor Science and Technology
• /
• v.28 no.6
• /
• pp.390-394
• /
• 2019

This paper presents an inkjet-printed plastic force sensor using PEDOT:PSS. Using a piezoelectric-type inkjet printer, the force sensor was manufactured by printing PEDOT:PSS ink onto a polyimide (PI) substrate film. Applying a vertical force of 0 to 100 N to the force sensor on the PI substrate with a thickness of 64 mm, the resistance of the force sensor increased in proportion to the input force by the length deformation of the PI substrates and the sensor pattern. As a result, the fabricated sensor has a characteristic of 0.001% /N with a linearity of 99.38%. In addition, as the thickness of the PI substrate film increased, the sensitivity of the sensor increased linearly. The fabricated force sensor is expected to be applied to industrial sites and healthcare fields.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.205-206
• /
• 2008

The transparent conductive film was prepared by bar coating method of poly (3, 4-ethylenedioxythiophene) (PEDOT) and poly (sodium 4-stylenesulfonate) grafted multi-walled carbon nanotubes (MWNT-PSS) nanocomposites solution on the polyethylene terephthalate (PET) film. In this case, multi-wall carbon nanotubes was treated by chemical methods to obtain water soluble MWNT-PSS and then blending with PEDOT. The non-covalent bonding of polymer to the MWNT surface was confirmed by Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA) and Transmission electro microscope (TEM) investigation also showed a polymer-wrapped MWNT structure. Furthermore, the electrical, transmission properties of the transparent conductive film were investigated and compared with control samples are raw PEDOT films.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.469.1-469.1
• /
• 2014

일반적으로 유기전자소자의 제작에 있어서 Indium tin oxide (ITO)는 뛰어난 전기 광학적 특성을 바탕으로 가장 보편적으로 사용되는 투명전극이다. 특히 유기태양전지(Organic Photovoltaic, OPV)나 유기발광디스플레이(Organic Light Emitting Device)는 ITO 위에 PEDOT:PSS 층을 형성하여 HOMO, LUMO를 조절하고 효율을 향상시키는 역할을 수행하고 있다. 특히 ITO 위의 PEDOT:PSS는 사용되는 용제의 종류나 첨가제 등에 따라 특성이 크게 영향을 받는다. 이때 PEDOT:PSS는 일반적으로 강산성을 띄게 됨으로써 유기전자소자의 장시간 안정성을 저하시키는 원인으로 작용한다. 본 연구에서는 각각 다른 pH level을 가진 PEDOT:PSS의 시간 경과에 따라 투과도와 면저항을 측정하고 각각의 PEDOT을 사용하여 유기태양전지 소자를 제작하였다. 소자제작 30일 경과 후 소자의 효율이 감소하기는 하였으나 그 변화가 일반적으로 사용되는 pH 2의 감소보다 현저히 적었음을 알 수 있다. 이러한 pH 변화가 이를 적용한 투명전극 필름의 전기 광학적 특성인 투과도 면저항 등에는 영항을 거의 미치지 않으면서도 OPV의 효율 변화에는 큰 차이를 보이는 것을 알 수 있다.

• Polymer(Korea)
• /
• v.38 no.2
• /
• pp.180-187
• /
• 2014

Nanocomposites including graphene oxide (GO) and conducting polymers (PPy, PANI and PEDOT) were prepared via an in-situ chemical polymerization process, and their characteristic properties depending upon the change of conducting polymer (CP) content were analyzed. A confirmation was made on not only the functional groups formed in GO but also the presence of CP existent in the nanocomposites. The molecular interaction between GO and poly(4-styrene sulfonic acid) (PSSA) or CP in the nanocomposites was proposed. With the increase of PEDOT content in the GOPSS/PEDOT nanocomposite, the estimated value of $I_D/I_G$ regarding the Raman analysis of them was decreased and a major change of their Raman spectra characteristic peaks was observed. In the GO-PSS/PEDOT nanocomposite, PEDOT molecules made an exfoliation of GO-PSSA layers and thus they were intercalated among layers. Such a unique molecular morphology induced the highest electrical conductivity for the GO-PSS/PEDOT nanocomposite among three kinds of nanocomposites prepared in this study. It is also noted that the uniform morphology confirmed in this study helped a thermal stability improvement in the nanocomposite due to the presence of GO or GO-PSSA acting as a thermal barrier.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.1
• /
• pp.8-17
• /
• 2023

In conventional liquid crystal display(LCD) manufacturing process, Indium Tin Oxide(ITO) as transparent electrode and rubbing process of polyimide as alignment layer are essential process to apply electric field and align liquid crystal molecules. However, there are some limits that deposition of ITO requires high vacuum state, and rubbing process might damage the device with tribolectric discharge. In this paper, we made nanocomposite with PEDOT:PSS and MWNT to replace ITO and constructed alignment layer by nano imprint lithography with nano wrinkle pattern, to replace rubbing process. These replacement made that only one PEDOT:PSS/MWNT film can function as two layers of ITO and polyimide alignment layer, which means simplification of process. Transferred nano wrinkle patterns functioned well as alignment layer, and we found out lowered threshold voltage and shortened response time as MWNT content increase, which is related to increment of electric conductivity of the film. Through this study, it may able to contribute to process simplification, reducing process cost, and suggesting a solution to disadvantage of rubbing process.