Azo-pyrene-based fluorescent sensor of reductive cleavage of isomeric azo functional group

Na Joo, H.,huy Le, B.,Jun Seo, Y. Pergamon Press ; Elsevier Science Ltd 2017 Tetrahedron letters: the international organ for t Vol.58 No.7

In this study we investigated the reductive azo cleavage of an azo compound presenting a pyrene fluorophore (Azo-py). Because of dramatic changes in its fluorescence, Azo-py could be used as a monitoring system for the reductive azo cleavage. Electron transfer from the pyrene unit to the azo moiety induced fluorescence quenching; this quenched fluorescence was recovered after the reductive azo cleavage. IR and NMR spectroscopy were used to study the various structural states. The rate of reductive cleavage of the azo compound, determined through fluorescence monitoring, depended on its structural state: the cleavage of trans-Azo-py was much faster than that of the cis-Azo-py. Furthermore, the Azo-py fluorophore was highly sensitive to the presence of zinc, but not other metal compounds, and the pH.

Cu₂ZnSn(S,Se)₄ (CZTSSe) 박막 태양전지 적용을 위한 마그네트론 스퍼터링으로 증착된 AZO/Ag/AZO 투명전극의 특성

이동민,장준성,김지훈,이인재,이병훈,조은애,김진혁,Lee, Dong Min,Jang, Jun Sung,Kim, Jihun,Lee, InJae,Lee, Byeong Hoon,Jo, Eunae,Kim, Jin Hyeok 한국재료학회 2020 한국재료학회지 Vol.30 No.6

Recent advances in technology using ultra-thin noble metal film in oxide/metal/oxide structures have attracted attention because this material is a promising alternative to meet the needs of transparent conduction electrodes (TCE). AZO/Ag/AZO multilayer films are prepared by magnetron sputtering for Cu₂ZnSn(S,Se)₄ (CZTSSe) of kesterite solar cells. It is shown that the electrical and optical properties of the AZO/Ag/AZO multilayer films can be improved by the very low resistivity and surface plasmon effects due to the deposition of different thicknesses of Ag layer between oxide layers fixed at AZO 30 nm. The AZO/Ag/AZO multilayer films of Ag 15 nm show high mobility of 26.4 ㎠/Vs and low resistivity and sheet resistance of 3.58^⁎10^-5 Ωcm and 5.0 Ω/sq. Also, the AZO/Ag (15 nm)/AZO multilayer film shows relatively high transmittance of more than 65 % in the visible region. Through this, we fabricated CZTSSe thin film solar cells with 7.51 % efficiency by improving the short-circuit current density and fill factor to 27.7 mV/㎠ and 62 %, respectively.

Utilization of AZO/Au/AZO multilayer electrodes instead of FTO for perovskite solar cells

Dang, Tran-Van,Pammi, S.V.N.,Choi, Jihoon,Yoon, Soon-Gil Elsevier 2017 Solar energy materials and solar cells Vol.163 No.-

<P><B>Abstract</B></P> <P>Aluminum (3at%)-doped ZnO (AZO)/Au/AZO multilayer films with low resistivity and high transmittance are in situ deposited at room temperature via facing-target sputtering for AZO and direct current (DC) sputtering for Au. The optical and electrical properties of multilayer films are compared with conventionally (<I>on</I>-axis) sputtered and facing-target sputtered (FTS) AZO films. The FTS samples show better crystallinity than that of <I>on</I>-axis sputtered samples, and the lowest value for resistivity is 7.9×10<SUP>−5</SUP> Ω-cm at an Au layer thickness of 8nm, which is compared with that of a conventional FTO electrode. The photo-conversion efficiencies (PCE) of the perovskite solar cells based on the AZO multilayer electrodes deposited via FTS and <I>on</I>-axis sputtering are 9.5% and 8.2%, respectively. Although the PCE of AZO multilayer-based-solar cells exhibit a lower efficiency than that of the FTO based-devices (~12.3%), the perovskite solar cell performance based on the FTS AZO multilayer electrodes is very attractive for applications to flexible planar-structured solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Utilization of the AZO/Au/AZO multilayer electrodes for perovskite solar cells. </LI> <LI> Low resistivity and high transmittance of AZO/Au/AZO deposited at room temperature via FTS. </LI> <LI> Damage-free FTS method from the plasma for multilayer electrodes. </LI> <LI> Achievement of high photo-conversion efficiency (~9.5%) using multilayer electrodes deposited via FTS. </LI> </UL> </P>

Characteristics of IZO/AZO and AZO/IZO Bi-layer Transparent Conducting Thin Films Prepared by Using PLD

Dongkyun Shin,Jin Hyun Shin,이희영,이재열,이세종 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10

AZO/IZO and IZO/AZO bi-layer thin films were deposited on the glass substrates by using pulsed laser deposition (PLD). The crystallinity and the texture of the thin film depend on the sequence of deposition of the IZO layer and the AZO layer. The crystal structures, the electrical and optical properties of the AZO/IZO and the IZO/AZO thin film were analyzed and compared using X-ray diffraction, field-emission scanning electron microscope, Hall measurements and UV spectrometry. The IZO/AZO bi-layer thin film showed a highly-oriented texture of IZO along the <111> axis, which implied that the c-axis-oriented AZO buffer layer enhanced the tendency of the IZO thin film to grow preferentially along the <111> axis. On the other hand, the AZO/IZO thin film did not revealed oriented grain growth of the AZO layer, which indicated that randomly- oriented IZO buffer layer suppressed the tendency of the AZO thin film to grow preferentially along the c-axis. The AZO/IZO and the IZO/AZO bi-layer thin films showed the average values of the AZO and the IZO monolayers for the electrical resistivity and the optical band gap.

The influence of Ni layer and thickness of AZO layers on the optoelectronic properties of AZO/Ni/AZO tri-layer deposited at room temperature

Kumar, M.M.D.,Mi Baek, S.,Kim, J. North-Holland 2014 Materials letters Vol.137 No.-

A thin Ni film was employed to improve electrical performances of aluminum-doped-zinc-oxide (AZO). AZO thickness was modulated to find an optimum combination for AZO/Ni/AZO tri-layer. A combination of AZO/Ni/AZO (50nm/5nm/50nm) substantially improves carrier mobility 34.5cm<SUP>2</SUP>V<SUP>-1</SUP>S<SUP>-1</SUP> from 1.96cm<SUP>2</SUP>V<SUP>-1</SUP>S<SUP>-1</SUP> of bilayer AZO/AZO (50nm/50nm) film. Although, Ni-insertion sacrifices the optical transmittance, the AZO/Ni/AZO structure effectively enhances the figure of merit (FOM) values. We report that the optical and electrical properties of AZO layers could be enriched by embedding a thin Ni film in AZO layers with tuning the thickness of AZO layers.

Textured-AZO/AZO/Glass 투명전극을 갖는 염료감응 태양전지의 광전변환 특성

서빙,박춘배,황근창,Xu, Bing,Park, Choon-Bae,Hoang, Geun-C. 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.1

We were studied that AZO conductive thin film can substitute for FTO electrode in dye sensitized solar cell. Three types of AZO films were deposited on soda-lime glass(AZO/glass, AZO/AZO/glass, textured AZO/AZO/glass) using RF magnetron sputtering process and investigated their properties of electrical, optical, and photoelectric conversion rate. The textured AZO/AZO/glass has the lowest resistivity of $3.079{\times}10^{-4}\;{\Omega}cm$ among other films. And the optical transmittance rate was better than both non textured AZO/AZO/glass and FTO/glass in the visible region. After manufacturing dye solar cells using the three types of AZO films, the textured AZO/AZO/glass showed the highest photoelectric conversion rate of 3.68% among AZO samples. But the transformation rate was slightly lower than FTO cells (4.52%). However, the conductive film of textured AZO/AZO/glass can be applicable to use an electrode in solar cells as cost-effective products.

AZO 및 ITO박막의 습열과 수소 플라즈마에 대한 안정성

김화민,류성원 한국물리학회 2008 새물리 Vol.56 No.1

AZO films were fabricated on Corning$\sharp$7059 glass by using the conventional rf-magnetron sputtering method with an Al-doped ZnO target. Their optical and electrical properties wee investigated as a functions of the film thickness. The stabilities of the optical and the electrical properties of the films treated with moist heat and hydrogen plasma were also investigated. The stability of the films treated with moist heat was evaluated as a change in the electrical resistivity of AZO film after heat treatment at temperatures below 600 $^\circ$C in air. The stability of the films treated with a hydrogen plasma was also evaluated as a change in the electrical resistivity and the optical transmittance of the AZO films as a function of substrate temperature during hydrogen plasma treatment in a Plasma Enhanced Convention Vapor deposition (PECVD) chamber. The stabilities of AZO were compared to those of a polycrystalline-ITO film (Corning Co.). For p-ITO films, the optical trnsmittance decreased significantly with increasing sample surface temperature during hydrogen plasma treatment for 30 min. The transmittance of the ITO film dropped to 20 $\sim$ 30\% and its conductivity was greatly decreased after exposure to a hydrogen plasma for 30 min at 300 $^\circ$C For the AZO film, there was no optical loss, but the optical band gap increased due to hydrogen incorporation into the film, indicating a Burstein-Moss effect. Al이 2 wt.\% 도핑된 ZnO 타겟을 사용하여 rf magnetron sputtering법으로 corning $\sharp$7059 유리 기판 위에 AZO 박막을 제작하였다. 제작된 AZO 박막에 대하여 전기 $\cdot$ 광학적 특성을 박막 두께의 함수로 조사하였으며, 또한 습열 (moist heat)과 수소 플라즈마에 대한 AZO박막의 전기·광학적 안정성 또한 조사되었다. 습열에 대한 안정성은 공기중에서 600 $^\circ$C이하의 온도에서 열처리 후, AZO박막의 면저항 변화로 평가하였으며, 수소 플라즈마에 대한 안정성은 PE-CVD챔버 내에서 수소 플라즈마 처리를 하는 동안 기판 온도의 함수로써 박막의 광투과도 변화로 평가하였다. AZO박막의 전기·광학적 안정성에 대한 결과는 다결정 ITO(p-ITO)박막 또는 비정질 ITO(a-ITO) 박막의 안정성과 비교하였다. p-ITO 박막에 대해서 광투과도는 수소 플라즈마 처리를 하는 동안 기판의 온도가 증가할 수록 현저하게 감소한다. 특히 p-ITO 박막의 광투과도는 300 $^\circ$C에서 수소 플라즈마에 30 분간 노출된후, 20 $\sim$ 30 \%로 떨어질 뿐만 아니라, 전기 전도성 또한 크게 감소한다. 반면, AZO박막의 경우 수소 플라즈마 처리 후 광투과도와 전기전도도 손실은 나타나지 않았으며, 오히려 박막 내에 혼합된 수소에 의해 광학적 띠 간격이 증가하는 Burstein moss 효과가 관측되었다.

증착 및 열처리 조건에 따른 AZO/Cu/AZO 박막의 전기적 ‧ 광학적 특성 평가

김찬영,임하은,양가은,권숙정,강찬희,임상철,이택영 한국재료학회 2023 한국재료학회지 Vol.33 No.4

AZO/Cu/AZO thin films were deposited on glass by RF magnetron sputtering. The specimens showed the preferred orientation of (0002) AZO and (111) Cu. The Cu crystal sizes increased from about 3.7 nm to about 8.5 nm with increasing Cu thickness, and from about 6.3 nm to about 9.5 nm with increasing heat treatment temperatures. The sizes of AZO crystals were almost independent of the Cu thickness, and increased slightly with heat treatment temperature. The residual stress of AZO after heat treatment also increased compressively from -4.6 GPa to -5.6 GPa with increasing heat treatment temperature. The increase in crystal size resulted from grain growth, and the increase in stress resulted from the decrease in defects that accompanied grain growth, and the thermal stress during cooling from heat treatment temperature to room temperature. From the PL spectra, the decrease in defects during heat treatment resulted in the increased intensity. The electrical resistivities of the 4 nm Cu film were 5.9 × 10-4 Ω ‧ cm and about 1.0 × 10-4 Ω ‧ cm for thicker Cu films. The resistivity decreased as the temperature of heat treatment increased. As the Cu thickness increased, an increase in carrier concentration resulted, as the fraction of AZO/Cu/AZO metal film increased. And the increase in carrier concentration with increasing heat treatment temperature might result from the diffusion of Cu ions into AZO. Transmittance decreased with increasing Cu thicknesses, and reached a maximum near the 500 nm wavelength after being heat treated at 200 °C.

Improved Electrical Properties of Indium Gallium Zinc Oxide Thin -Film Transistors by AZO/Ag/AZO Multilayer Electrode

( Young Soo No ),( Jeong Do Yang ),( Dong Hee Park ),( Tae Whan Kim ),( Ji Won Choi ),( Won Kook Choi ) 한국센서학회 2013 센서학회지 Vol.22 No.2

We fabricated an a-IGZO thin film transistor (TFT) with AZO/Ag/AZO transparent multilayer source/drain contacts by rf magnetron sputtering. a-IGZO TFT with AZO/Ag/AZO multilayer S/D electrodes (W/L = 400/50 μm) showed a subs-threshold swing of 3.78 V/dec, a minimum off-current of 10-12 A, a threshold voltage of 0.41 V, a field effect mobility of 10.86 cm2/Vs, and an on/off ratio of 9x10^9. From the ultraviolet photoemission spectroscopy, it was revealed that the enhanced electrical performance resulted from the lowering of the Schottky barrier between a-IGZO and Ag due to the insertion of an AZO layer and thus the AZO/Ag/AZO multilayer would be very appropriate for a promising S/D contact material for the fabrication of high performance TFTs.

산업진흥기술 : 결정질AZO 박막과 비정질IGZO 박막의 결정구조와 결합에너지와의 상관성

소영호 ( Young Ho So ),송정호 ( Jung Ho Song ),서동명 ( Dong Myung Seo ),오데레사 ( Teresa Oh ) 산업진흥원 2016 산업진흥연구 Vol.1 No.1

산화물반도체의 결정질특성과 비정질특성을 이해하기 이하여 AZO 박막과 IGZO 박막을 증착하고 열처리하여 물리적 화학적인 특성을 비교하였다. AZO 박막은 열처리온도가 올라갈수록 결정성이 높아졌으나 IGZO 박막은 열처리온도가 높을수록 비정질특성이 우수하였다. AZO 박막은 열처리에 따라서 PL, XPS 분석에서 화학적 이동이 나타났으나 IGZO 박막은 화학적 이동이 나타나지 않았다. AZO의 O 1s 결합 에너지는 531.5 eV였으며, IGZO 박막은 530 eV으로 낮았다. To research the correlation between the amorphous and crystal structure of oxide semiconductors, AZO and IGZO films were deposited and annealed with various temperatures in a vacuum state. AZO increased the degree of crystal structure with increasing the annealing temperature, but IGZO became an amorphous structure after the annealing process at high temperature. The series of AZO films with various annealing temperatures showed the chemical shift from the analyzer of PL and O 1s spectra, but the results of IGZO films by PL and O 1s spectra were not observed the chemical shift. The binding energy of oxygen vacancy of AZO with a crystal structure was 531.5 eV, and that of IGZO with an amorphous structure was 530 eV as a lower binding energy.