• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1103-1107
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• 2005

Single-crystal silicon thin films on glass (SOG) and on fused-quartz (SOQ) were prepared using wafer bonding and hydrogen-induced layer transfer. Thinfilm transistors (TFTs) were subsequently fabricated. The high-temperature processed SOQ TFTs show better device performance than the low-temperature processed SOG TFTs. Tensile and compressive strain was measured respectively on SOQ and SOG. Consistent with the tensile strain, enhanced electron effective mobility was measured on the SOQ TFTs.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.634-634
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• 2013

Transfer molding methods have a problem that weak adhesion between nanostructures and substrates. It is important to make various nano scale applications, also the stability of nanostructure on substrate is related with device performance. We studied an effect of poly 4-vinylphenol (PVP) as the polymeric adhesion layer between organic nanowires and a Si substrate when the nanowires are transferred by liquid-bridge-mediated nanotransfer molding method (LB-nTM). Their structural stability was examined by optical microscopy, scanning electron microscopy as multiple transfer molding and washing process. Field-effect transistors were fabricated with organic semiconductor nanowires on a polymeric adhesion layer and their electrical properties showed no significant difference as the one without the adhesion layer. As a result, adhesion layer can be used in the washing process and making multi-layer nano-scale patterns.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1034-1037
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• 2002

In this study, we fabricated red organic electrolu-minescent device with a doping material (DCJTB), and The cell structure used ITO:indium tin oxide $[20{\Omega}]$/CuPc:Hole injection layer 20nm/NPB: Hole transfer layer 40nm/$Alq_3$ (host) + DCJTB(1% or 3%) (guest) Emitting layer 40nm/$Alq_3$ : Electron transfer layer 30nm/Al :Cathode layer 150nm. the luminescent layer consisted of a host material. 8-hydrozyquinoline aluminum $(Alq_3)$, and DCJTB dye as the dopant. a stable red emission (chromaticity coordinates : x=0.64, y=0.36) was obtained in this cell with the luminance range of $100-600cd/m^2$. we study the electrical and optical properties of devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.458-458
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• 2011

Graphene, a single atomic layer of sp2-bonded carbon, shows substantial potential for various applications. Chemical manipulation of its electronic properties will be of great importance. In this study, we have investigated interaction between graphene and organic molecular layer of tetrafluorotetracyanoquinodimethane (F4-TCNQ), a strong electron acceptor. F4-TCNQ films of varying thickness were evaporated onto graphene mechanically exfoliated on SiO2/Si substrates. F4-TCNQ molecules increase the frequencies of Raman G and 2D bands of graphene while decreasing the linewidth of G band and 2D/G intensity ratio, which is consistent with increase of hole density in graphene. These results exemplify the possibility of chemical tuning of electronic properties of graphene.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.169-171
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• 2007

A breaking layer was introduced to conventional decal transfer method in membrane electrolyte assembly fabrication for high catalyst transfer ratio. In this study, the modified decal transfer method with high catalyst transfer ratio was introduced and its performance is studied. The structural features of electrodes made by decal method were investigated using scanning electron microscopy and current-voltage polarization measurement.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.853-858
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• 2008

The structure of organic light-emitting diodes(OLEDs) with typical heterostructure consists of anode, hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, and cathode. 4,4bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl(NPB) used as a hole transport layer and 4'4-bis(2,2'-diphenyl vinyl)-1,1'-biphenyl(DPVBi) used as a blue light emitting layer were graded-mixed at selected ratio. Interface at heterojunction between the hole transport layer and the elecrtron transport layer restricts carrier's transfer. Mixing of the hole transport layer and the emitting layer reduces abrupt interface between the hole transport layer and the electron transport layer. The operating voltage of OLED devices with graded mixed-layer structure is 2.8 V at 1 $cd/m^2$ which is significantly lower than that of OLED device with typical heterostructure. The luminance of OLED devices with graded mixed-layer structure is 21,000 $cd/m^2$ , which is much higher than that of OLED device with typical heterostructure. This indicates that the graded mixed-layer enhances the movement of carriers by reducing the discontinuity of highest occupied molecular orbital(HOMO) of the interface between hole transport layer and emitting layer.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.120-124
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• 1986

In order to investigate effective solar energy conversion system, the light-induced electron transfer reactions have been examined across single-lamellar liposomes incorporated organic photosensitizers such as anthracene and naphthalene derivatives. We have observed photosensitized reduction of methyl viologen (1,1'-dimethyl-4,4'-$bipyridinium^{2+}$) dissolved in the exterior aqueous phase of the pigmented phospholipid liposomes when EDTA, as electron donor, is dissolved in the enclosed aqueous phase of the liposomes. The anthroyl stearic acid incorporated in the hydrophobic bilayer of liposomes leads to much less quantum yield for the photosensitized reduction of $MV^{2+}$ than the anthracene carboxylate incorporated in the outer hydrophilic layer. However, ${\beta}$-carotene with anthroyl stearic acid incorporated into the bilayer enhances the quantum yield significantly (${\Phi}{\simeq}0.2-0.3$), preventing the reverse reaction of electron transfer ($MV^+_\ {\rightarrow}MV^{2+}$) so that it might be useful for solar energy conversion into chemical energy. A naphthalene derivative, octadecyl naphthylamine sulfonic acid incorporated into the outer layer of liposomes results in less efficiency of $MV^{2+}$ reduction than anthroyl stearic acid. These results have been also tested with respect to lipid components of liposomes.

• 한국재료학회지
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• 제32권2호
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• pp.94-97
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• 2022

We fabricated 3 types of ETL, mp TiO₂, ZnO, and ZnO coated on mp TiO₂(ZMT) to compare the photoelectric conversion efficiency (PCE) and fill factor (FF) of Perovskite solar cells. The structure of the cells was FTO/ETL/Perovskite (CH₃NH₃PbI₃)/spiro-MeOTAD/Ag. SEM morphology assessment of the ETLs showed that mp TiO₂ was porous, ZnO was flat, and the ZMT porous surface was filled with a thin layer. Via XRD measurements, the crystal structures of mp TiO₂ and ZnO ETL were found to be anatase and wurtzite, respectively. The XPS patterns showing energy bonding of mp TiO₂, ZnO, and ZMT O 1s confirmed these materials to be metal oxides such as ETL. The electrical characteristics of the Perovskite solar cells were measured using a solar simulator. Perovskite solar cells with ZMT ETL showed showed PCE of 10.29 % than that of conventional mp TiO₂ ETL devices. This was considered a result of preventing Perovskite from seeping into the ETL and preventing recombination of electrons and holes.

• 한국표면공학회지
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• 제45권1호
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• pp.15-19
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• 2012

Tris(8-quinolinolato)aluminum(III); $Alq_3$ has been frequently used as an electron transporting layer in organic light-emitting diodes. Either Ba with a low work function or Au with a high work function was deposited on $Alq_3$ layer in vacuum. And then, the behaviors of electron transition at the $Alq_3$/Ba and $Alq_3$/Au interfaces were investigated by using the near edge x-ray absorption fine structure (NEXAFS) spectroscopy. In the each interface, the energy levels of unoccupied obitals were assigned as ${\pi}^*$(LUMO, LUMO+1, LUMO+2 and LUMO+3) and ${\sigma}^*$. And the relative intensities of these peaks were investigated. In an oxygen atom composing $Alq_3$ molecule, the relative intensities for a transition from K-edge to LUMO+2 were largely increased as Ba coverage (${\Theta}_{Ba}$, 2.7 eV) with a low work function was in-situ sequentially increased on $Alq_3$ layer. In contrast, the relative intensities for the LUMO+2 peak were reduced as Au coverage (${\Theta}_{Au}$, 5.1 eV) with a high work function were increased on $Alq_3$ layer. This means that the electron transition by photon in oxygen atom which consists in the unoccupied orbitals in $Alq_3$ molecule, largely depends on work function of a metal. Meanwhile, in the case of electron transition in a carbon atom, as ${\Theta}_{Ba}$ was increased on $Alq_3$, the relative intensity from K-edge to ${\pi}_1{^*}$ (LUMO and LUMO+1) was slightly decreased, and from K-edge to ${\pi}_2{^*}$ (LUMO+2 and LUMO+3) was somewhat increased. This rising of the energy state from ${\pi}_1{^*}$ to ${\pi}_2{^*}$ exhibits that electrons provided by Ba would contribute to the process of electron transition in the $Alq_3$/Ba interfaces. As shown in above observation, the analyses of NEXAFS spectra in each interface could be important as a basic data to understand the process of electron transition by photon in pure organic materials.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.74-74
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• 2011

Polymer solar cells utilize bulk heterojunction (BHJ) type photo-active layer in which the electron donating polymer and electron accepting C60 derivatives are mixed together. In the BHJ system the electron donating polymer and electron accepting C60 derivatives are blended. The blended system causes charge recombination at the interface between the BHJ active layer and electrode. To reduce the charge recombination at the interface, it is needed to use an interlayer that can selectively transfer electrons or holes. We have developed solution processable wide band gap inorganic interfacial layers for polymer solar cells. The effect of interlayers on the performance of polymer solar cell was investigated for various types of conjugated polymers. We have found that inorganic interfacial layers enhanced the solar cell efficiency through the reduction of charge recombination at the interface between active layer and electrode. Furthermore, the stability of the polymer solar cell using the interlayer was significantly improved. The efficiency of 6.5% was obtained from the PTB7:PCBM70 based solar cells utilizing $TiO_2$nanoparticles as an interlayers.