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41.
Jin Hyuck Heo Dae Ho Song Basavaraj Rudragouda Patil Sang Hyuk Im 《Israel journal of chemistry》2015,55(9):966-977
Recently, innovative perovskite hybrid solar cells have attracted great interest in solar cell research fields, such as dye-sensitized solar cells, organic photovoltaics, thin-film solar cells, and silicon solar cells, because their device efficiencies are gradually approaching those of crystalline Si solar cells, and they can be fabricated by cheap low-temperature solution processes. Here, we review the recent progress of innovative perovskite hybrid solar cells. The introduction includes the general concerns about solar cells and why we need innovative solar cells. The second part explains the structure and the material properties of hybrid perovskite materials. We focus on why the hybrid perovskite materials can exhibit excellent solar cell properties, such as high open-circuit voltage. The third part introduces recent progress in innovative perovskite hybrid solar cells, in terms of device architecture and deposition methods for dense perovskite thin films with full surface coverage. The device architecture is important in attaining high power conversion efficiency; the device operating mechanism is dependent on the device structure; and the pinhole-free dense perovskite thin films with full surface coverage are crucial for achieving high efficiency. Finally, we summarize the recent progress in perovskite hybrid solar cells, and the issues to be solved, in the summary and outlook section. 相似文献
42.
Different with the conventional method of manufacturing poly(vinyl formal) (PVF) porous foam by using the pore‐forming agents such as wheat or potato starches, a novel method without using the pore‐forming agent is introduced in this article. Through the help of images taken by a scanning electron microscope, the formation process of the present PVF foam will be discussed in terms of the spinodal decomposition (SD) phase separation principle. Additionally, the effect of poly(vinyl alcohol) concentration and reaction temperature on the pore structure of the PVF foam will be investigated. Moreover, the water adsorption capacities of the PVF foams obtained by the present method will be studied in details through the analyses of pore‐size distribution, mechanical modulus, and thermal property. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41270. 相似文献
43.
44.
A Surface Tailoring Method of Ultrathin Polymer Gate Dielectrics for Organic Transistors: Improved Device Performance and the Thermal Stability Thereof 下载免费PDF全文
Hyejeong Seong Jieung Baek Kwanyong Pak Sung Gap Im 《Advanced functional materials》2015,25(28):4462-4469
Tailoring the surface of the dielectric layer is of critical importance to form a good interface with the following channel layer for organic thin film transistors (OTFTs). Here, a simple surface treatment method is applied onto an ultrathin (<15 nm) organosilicon‐based dielectric layer via the initiated chemical vapor deposition (iCVD) to make it compatible with organic semiconductors without degrading its insulating property. A molecular‐thin oxide capping layer is formed on a 15 nm thick poly(1,3,5‐trimetyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3) by a brief oxygen plasma treatment. The capping layer greatly enhances the thermal stability of the dielectrics, without degrading the original mechanical flexibility and insulating performance of the dielectrics. Moreover, the surface silanol functionalities formed by the plasma treatment can also be utilized for the surface modification with silane compounds. The surface‐modified dielectrics are applied to fabricate low‐voltage operating (<5 V) pentacene‐based OTFTs. The highest field‐effect mobility of the device with the surface‐treated 15 nm thick pV3D3 is 0.59 cm2 V?1 s?1, which is improved up to two times compared to the TFT with the pristine pV3D3. It is believed that the simple surface treatment method can widely extend the applicability of the highly robust, ultrathin, and flexible pV3D3 gate dielectrics to design the surface of the dielectrics to match well various kinds of organic semiconductors. 相似文献
45.
Jongseong Park Dae‐Hyeon Kim Su‐Jin Park Tae‐gon Lee Mir Im Jeong‐Seog Kim Sahn Nahm 《Journal of the American Ceramic Society》2016,99(7):2229-2232
A specimen having a stoichiometric composition of KSbO3·(KSb) calcined at 800°C has an R rhombohedral structure (RS), and changes to a Pn cubic structure (CS) when calcined at 1100°C. Finally, a <111>‐oriented rhombohedral phase is formed in the specimen calcined at 1230°C. K/Sb ratio decreases from 1.0 in RS, 0.93 in CS, and finally to 0.85 in <111>‐oriented rhombohedral phases. On the other hand, a specimen having a K‐excess composition of K1.1SbO3 calcined at 800°C shows a RS that is maintained in the K‐excess specimen calcined at 1230°C. The composition of these specimens is very close to KSb. Therefore, the RS with a space group of R is a stable form of KSbO3. The formation of Pn cubic and <111>‐oriented R phases can be explained by the evaporation of K2O during the calcination process at temperatures above 1100°C. 相似文献
46.
Kwang-Hee Im In-Young Yang Sun-Kyu Kim Jong-An Jung Young-Tae Cho Yong-Deuck Woo 《Journal of Mechanical Science and Technology》2016,30(10):4413-4416
Terahertz ray (T-ray) scanning applications are promising tools. The use of T-ray for nondestructive evaluation was investigated on composite materials. In this characterization procedure, electromagnetic properties, such as the refractive index, were analyzed. The estimates of properties are in good agreement with known data. We successfully demonstrated the characteristics of T-ray propagating through Carbon fiber-reinforced plastic (CFRP) composites to acquire the refractive index by using the characterized material properties. A T-ray technique was developed for measuring paint thickness on CFRP laminates. Good results were obtained from tests performed on standard paint samples with thickness starting from approximately 100 μm. The method was based on reflection mode measurement with time of flight. Another method developed for measuring paint thickness using resonance frequencies was utilized to determine paint thickness on composite laminates. The paint thickness deduced from resonance frequencies agrees well with the result obtained directly from time-domain echoes. 相似文献
47.
Charles W. Teplin Sachit Grover Adrian Chitu Alexander Limanov Monical Chahal James Im Daniel Amkreutz Stefan Gall Heayoung P. Yoon Vincenzo Lasalvia Paul Stradins Kim M. Jones Andrew G. Norman David L. Young Howard M. Branz Benjamin G. Lee 《Progress in Photovoltaics: Research and Applications》2015,23(7):909-917
We fabricate thin epitaxial crystal silicon solar cells on display glass and fused silica substrates overcoated with a silicon seed layer. To confirm the quality of hot‐wire chemical vapor deposition epitaxy, we grow a 2‐µm‐thick absorber on a (100) monocrystalline Si layer transfer seed on display glass and achieve 6.5% efficiency with an open circuit voltage (VOC) of 586 mV without light‐trapping features. This device enables the evaluation of seed layers on display glass. Using polycrystalline seeds formed from amorphous silicon by laser‐induced mixed phase solidification (MPS) and electron beam crystallization, we demonstrate 2.9%, 476 mV (MPS) and 4.1%, 551 mV (electron beam crystallization) solar cells. Grain boundaries likely limit the solar cell grown on the MPS seed layer, and we establish an upper bound for the grain boundary recombination velocity (SGB) of 1.6x104 cm/s. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
48.
Near‐infrared‐active and pH‐responsive fluorescent polymer‐integrated hybrid graphene oxide nanoparticles for the detection and treatment of cancer 下载免费PDF全文
Shazid Md. Sharker Eun Bi Kang Chun‐Im Shin Sung Han Kim Gibaek Lee Sung Young Park 《应用聚合物科学杂志》2016,133(32)
Hybrid nanoparticles for theragnosis have great potentiality to bring desire functionalities in one integrated system. The development of bioimaging guided photothermal therapy (PTT) is pivotal in optimizing cytotoxic cancer therapy. We report near‐infrared (NIR)‐active and pH‐responsive fluorescent, catechol‐conjugated, reduced graphene oxide (rGO)‐anchored hybrid nanoparticles that can sharply increase the photothermal heat in response to NIR exposure and exhibit pH‐dependent fluorescence emission for the detection of tumor areas without causing cell toxicity. The optoelectronic absorption property of poly(3,4‐ethylenedioxythiophene) [PEDOT]:dopamine‐conjugated poly(4‐styrenesulfonate‐co‐maleic acid) [D‐PSM] and 3′,4′‐dihydroxyacetophenone/boron‐dipyrromethene [CCDP/BODIPY]‐quaternized polyethylene glycol grafted poly(dimethylaminoethyl methacrylate) (C/B‐PgP) present in this hybrid nanoparticles resulted in efficient photothermal conversion with pH‐tunable fluorescence that exerted sufficient photothermal cytotoxicity to cancer cells. The in vitro cellular uptake was measured by confocal laser scanning microscopy, allowing the therapeutic efficiency and bioimaging effects to be explored. We expect that the broad optical absorption property of PEDOT:D‐PSM with BODIPY‐conjugated polymers on rGO sheets would get tremendous attraction in this enormous rising PTT with cancer detectable biomarker. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43791. 相似文献
49.
Jong-Soo Kim Yong-Bim Im Ngoc-Hung Bui 《Journal of Mechanical Science and Technology》2005,19(9):1790-1800
The examination on the operating mechanism of a pulsating heat pipe (PHP) using visualization revealed that the working fluid
in the PHP oscillated to the axial direction by the contraction and expansion of vapor plugs. This contraction and expansion
is due to the formation and extinction of bubbles in the evaporating and condensing section, respectively. In this paper,
a theoretical model of PHP was presented. The theoretical model was based on the separated flow model with two liquid slugs
and three vapor plugs. The results show that the diameter, surface tension and charge ratio of working fluid have significant
effects on the performance of the PHP. The following conclusions were obtained. The periodic oscillations of liquid slugs
and vapor plugs were obtained under specified parameters. When the hydraulic diameter of the PHP was increased to d=3mm, the
frequency of oscillation decreased. By increasing the charging ratio from 40 to 60 by volume ratio, the pressure difference
between the evaporating section and condensing section increased, the amplitude of oscillation reduced, and the oscillation
frequency decreased. The working fluid with higher surface tension resulted in an increase in the amplitude and frequency
of oscillation. Also the average temperature of vapor plugs decreased. 相似文献
50.
Crude extract and solvent-partitioned fraction of Glehnia littoralis were found to possess different anti-proliferative effects against AGS, HT1080 and U937 human cancer cells. The crude extracts and solvent fractions dose-dependently inhibited cell proliferation. Especially, n-hexane and 85% aqueous MeOH fractions exhibited comparatively higher anti-proliferative effects and reduced expressions of Bcl-2, COX-2 and iNOS genes. Systematic separation of all solvent fractions by chromatographic methods led to the isolation of three glucopyranosides, four furanocoumarins and two polyacetylenic alcohols. All the nine compounds were evaluated for their inhibitory effects against both proliferation of human cancer cells and expressions of MMP-2 and -9 in HT1080 cells. Two polyacetylenic alcohols exerted the highest inhibitory activity against both human cancer cell lines, and MMP-2 and -9. These results suggest that G. littoralis may possibly be used as a valuable chemopreventive agent or food supplement for reducing cancer risk. 相似文献