• 한국광학회:학술대회논문집
• /
• 한국광학회 2008년도 하계학술발표회 논문집
• /
• pp.213-214
• /
• 2008

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.321-321
• /
• 2010

The PEDOT:PSS layer is usually used as hole transporting layer for the polymer bulk heterojunction solar cells. However, the interface between ITO and PEDOT:PSS is not stable and the chemical reaction between ITO and PEDOT can result in degraded device performance. We used the tungsten oxides as a hole transport layer by spin-coating. The $WO_3$ nanoparticles were well dispersed in ammonium hydroxide and deionized water and formed thin layer on the ITO anode. We found that $WO_3$ surface is more hydrophobic than the bare ITO or PEDOT:PSS-coated surfaces. The hydrophobic surfaces promote an ordered growth of P3HT films. A higher degree of P3HT ordering is expected to improve the hole mobility and the lifetime of the device using the tungsten oxide showed better stability compared to the device using the PEDOT:PSS.

• 한국재료학회지
• /
• 제29권8호
• /
• pp.491-496
• /
• 2019

In this study, we prepare pure $WO_3$ inverse opal(IO) film with a thickness of approximately $3{\mu}m$ by electrodeposition, and an ultra-thin $TiO_2$ layer having a thickness of 2 nm is deposited on $WO_3$ IO film by atomic layer deposition. Both sets of photoelectrochemical properties are evaluated after developing dye-sensitized solar cells(DSSCs). In addition, morphological, crystalline and optical properties of the developed films are evaluated through field-emission scanning electron microscopy(FE-SEM), High-resolution transmission electron microscopy(HR-TEM), X-ray diffraction(XRD) and UV/visible/infrared spectrophotometry. In particular, pure $WO_3$ IO based DSSCs show low $V_{OC}$, $J_{SC}$ and fill factor of 0.25 V, $0.89mA/cm^2$ and 18.9 %, achieving an efficiency of 0.04 %, whereas the $TiO_2/WO_3$ IO based DSSCs exhibit $V_{OC}$, $J_{SC}$ and fill factor of 0.57 V, $1.18mA/cm^2$ and 50.1 %, revealing an overall conversion efficiency of 0.34 %, probably attributable to the high dye adsorption and suppressed charge recombination reaction.

• 대한방사선기술학회지:방사선기술과학
• /
• 제1권1호
• /
• pp.15-24
• /
• 1978

The characteristics of the rare earth phosphors intensifying screen (LM-6, Grenex-8) as compared with $CaWO_4$ intensifying screen had been studied utilizing several common x-ray films, and found the following results. 1. Compared with the conventional CaWO4 intensifying screen, the rare earth phosphors intensifying screen was found to be more sensitive over to 1.26-3.47 times. So the radiation exposure could be reduced to 1/1.26 -1/3.47. 2. Sharpness as well as the film speed were both increased. So the motion blurring and geometrical unsharpness could be decreased. 3. In spite of that the film speed was increased, photographic contrast was kept up. Therefore, the more ideal film of greater latitude could be obtained. 4. The effects of the rare earth phosphors intensifying screen would be much increased as using with orthochromatic x-ray films.

• 한국산학기술학회논문지
• /
• 제17권7호
• /
• pp.420-424
• /
• 2016

본 연구에서는 지속적으로 심각한 대기오염의 문제로 실내 공기청정의 중요성이 대두되는 점을 감안하여 광촉매 단위기술을 개발하고자 건식 박막 공정 중 일반적으로 사용되어지는 RF 마그네트론 스퍼터링을 이용하여 $WO_3$ 단층막을 증착하였다. 초기 진공도는 $1.8{\times}10^{-6}$ [Torr]를 기준하여 최적의 스퍼터링 공정조건인 RF 100[W], 7[mTorr]진공 조건에서 Ar:$O_2$ 반응가스의 비율을 70[sccm] : 2[sccm]으로 하여 제작된 $WO_3$ 단층막은 380[nm]-780[nm]의 가시광 영역에서 80% 이상의 높고 일정한 광투과 특성을 확인하였다. 공기 청정 효과를 확인 위해 제작된 $WO_3$ 박막의 광촉매 특성을 조사하기 위해 메틸렌블루 내에서의 흡광도 및 농도변화를 광조사 시간 변화에 따라 측정하였다. 그 흡광도 측정결과 시간에 따라 흡광도 특성이 보임을 확인하였고, 5시간 경과 후 기존 메틸렌블루 농도 대비 80% 수준의 농도로 낮아지는 것을 확인하였다. 이런 결과로 부터 스퍼터링법에 의해 제작된 기능성 $WO_3$박막의 광분해 특성을 통해 형광등의 반사갓 혹은 LED등의 렌즈에 활용 된다면 차세대 조명원의 공기청정 효과를 증진시킬 수 있는 박막을 개발하였다.

• 센서학회지
• /
• 제24권1호
• /
• pp.15-21
• /
• 2015

Transparent and conductive multilayer thin films consisting of three alternating layers FZTO/Ag/$WO_3$ have been fabricated by radio-frequency (RF) sputtering for the applications as transparent conducting oxides and the structural and optical properties of the resulting films were carefully studied. The single layer fluorine doped zinc tin oxide (FZTO) and tungsten oxide ($WO_3$) films grown at room temperature are found to have an amorphous structure. Multilayer structured electrode with a few nm Ag layer embedded in FZTO/Ag/$WO_3$ (FAW) was fabricated and showed the optical transmittance of 87.60 % in the visible range (${\lambda}=380{\sim}770nm$), quite low electrical resistivity of ${\sim}10^{-5}{\Omega}cm$ and the corresponding figure of merit ($T^{10}/R_s$) is equivalent to $3.0{\times}10^{-2}{\Omega}^{-1}$. The resultant power conversion efficiency of 2.50% of the multilayer based OPV is lower than that of the reference commercial ITO. Asymmetric D/M/D multilayer is a promising transparent conducting electrode material due to its low resistivity, high transmittance, low temperature deposition and low cost components.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 추계학술대회 초록집
• /
• pp.99.2-99.2
• /
• 2011

Transparent conducting oxides (TCOs) supported on glass are widely used as substrates in PEC studies for photovoltaic hydrogen generation applications However, high sheet resistane ($10{\sim}15{\Omega}/cm^2$) and fragileness of glass-supported TCO substrates are the obstacles to produce the large area PEC cells. Such internal sheet resistance is detrimental to efficient collection of photogenerated majority charge carriers at the photoactive material and electrolyte interface. Moreover, these TCO substrates are very expensive and consume about 40~60% cost of the devices. Hence, a low sheet resistance of the substrate is a key point in improving the performance of PEC devices. Metallic substrates coated with a photoactive material would be a good choice for efficient charge collection. Such metal substrates based photanodes are best candidate for large-scale phtoelectrochemical water splitting for hydrogen generation. In this study, we report the enhanced PEC performance of $WO_3$ film on metal(chemical etched, bare) substrate. It is proposed that interface between $WO_3$ and the metal substrate is responsible for efficient charge transfer and demonstrated significant improvement in the photoelectrochmical performance. X-ray diffration and FESEM suduies reveled that $WO_3$ films are monoclinic, porous, polycrystalline with average grain size of ~50nm. Photocurrent of $WO_3$ prepared on metal substrates was measured in 0.5M $H_2SO_4$ electroyte under simulated $100mW/cm^2$ illumination.

• 한국세라믹학회지
• /
• 제41권2호
• /
• pp.97-101
• /
• 2004

W $O_{x}$-based semiconductor type thin film gas sensor was fabricated for the detection of N $O_{x}$ by reactive d.c. sputtering method. The relative oxidation state of the deposited W $O_{x}$ films was approximately compared by the calculation of the difference of the binding energy between Ols to W4 $f_{7}$2/ core level XPS spectra in the standard W $O_3$ powder of known composition. As the annealing temperature increased from 500 to 80$0^{\circ}C$, relative oxygen contents and grain size of the sputtered films were gradually increased. As the results of sensitivity ( $R_{gas}$/ $R_{air}$) measurements for the 5 ppm N $O_2$ gas, the sensitivity was 110 and the sensor showed recovery time as fast as 200 s. The other sensor properties were examined in terms of surface microstructure, annealing temperature, and relative oxygen contents. These results indicated that the W $O_3$ thin film with well controlled structure is a good candidate for monitoring and controlling of automobile exhaust.haust.t.t.t.

• 센서학회지
• /
• 제6권1호
• /
• pp.24-34
• /
• 1997

본 연구에서는 비정질 $WO_{3}$ 박막을 작용전극으로 $V_{2}O_{5}$ 박막과 NiO 박막을 각각의 대향전극으로 사용한 두 종류의 상보형 일렉트로크로믹 소자를 제작하고 그 특성을 조사 연구하였다. 그 결과 $100{\sim}150nm$ 두께로 진공증착된 $V_{2}O_{5}$ 박막을 대향전극으로 이용하여 제작된 $ITO/WO_{3}/LiClO_{4}-PC/V_{2}O_{5}/ITO$ 구조의 상보형 소자에서는 $1{\sim}2V$ 정도의 낮은 인가전압에서 광변조량이 $50{\sim}60%$를 나타내는 우수한 특성을 나타냈다. 그리고, RF 반응성 스퍼터링 방법으로 제작된 NiO 박막을 대향전극으로 이용한 $ITO/WO_{3}/LiClO_{4}-PC/NiO/ITO$ 구조의 경우 1.5V의 인가전압에 가시광선 영역(${\lambda}=550nm$)에서 약 25% 정도, 근적외선 영역(${\lambda}=850nm$)에서 약 30% 정도의 태양광을 변조할 수 있는 특성을 보였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.471-474
• /
• 2000

A flat type microgas sensor was fabricated on the p-type silicon wafer with low stress S $i_3$ $N_4$, whose thickness is 2${\mu}{\textrm}{m}$ using MEMS technology and its characteristics were investigated. W $O_3$thin film as a sensing material for detection of N $O_2$gas was deposited using a tungsten target by sputtering method, followed by thermal oxidation at several temperatures (40$0^{\circ}C$~$600^{\circ}C$) for one hour. N $O_2$gas sensitivities were investigated for the W $O_3$thin films with different annealing temperatures. The highest sensitivity when operating at 20$0^{\circ}C$ was obtained for the samples annealed at $600^{\circ}C$. As the results of XRD analysis, the annealed samples had polycrystalline phase mixed with triclinic and orthorhombic structures. The sample exhibit higher sensitivity when the system has less triclinic structure. The sensitivities, $R_{gas}$ $R_{air}$ operating at 20$0^{\circ}C$ to 5 ppm N $O_2$of the sample annealed at $600^{\circ}C$ were approximately 90. 90.