The Experts below are selected from a list of 67524 Experts worldwide ranked by ideXlab platform
Nam Gyu Park - One of the best experts on this subject based on the ideXlab platform.
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quantum dot Sensitized Solar Cell with unprecedentedly high photocurrent
Scientific Reports, 2013Co-Authors: Heewon Shin, Min Jae Ko, Seongju Hwang, Nam Gyu ParkAbstract:The reported photocurrent density (JSC) of PbS quantum dot (QD)-Sensitized Solar Cell was less than 19 mA/cm2 despite the capability to generate 38 mA/cm2, which results from inefficient electron injection and fast charge recombination. Here, we report on a PbS:Hg QD-Sensitized Solar Cell with an unprecedentedly high JSC of 30 mA/cm2. By Hg2+ doping into PbS, JSC is almost doubled with improved stability. Femtosecond transient study confirms that the improved JSC is due to enhanced electron injection and suppressed charge recombination. EXAFS reveals that Pb-S bond is reinforced and structural disorder is reduced by interstitially incorporated Hg2+, which is responsible for the enhanced electron injection, suppressed recombination and stability. Thanks to the extremely high JSC, power conversion efficiency of 5.6% is demonstrated at one sun illumination.
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6.5% efficient perovskite quantum-dot-Sensitized Solar Cell
Nanoscale, 2011Co-Authors: Jeong Hyeok Im, Chang Ryul Lee, Sang-won Park, Jin Wook Lee, Nam Gyu ParkAbstract:Highly efficient quantum-dot-Sensitized Solar Cell is fabricated using ca. 2-3 nm sized perovskite (CH(3)NH(3))PbI(3) nanocrystal. Spin-coating of the equimolar mixture of CH(3)NH(3)I and PbI(2) in gamma-butyrolactone solution (perovskite precursor solution) leads to (CH(3)NH(3))PbI(3) quantum dots (QDs) on nanocrystalline TiO(2) surface. By electrochemical junction with iodide/iodine based redox electrolyte, perovskite QD-Sensitized 3.6 mu m-thick TiO(2) film shows maximum external quantum efficiency (EQE) of 78.6% at 530 nm and Solar-to-electrical conversion efficiency of 6.54% at AM 1.5G 1 sun intensity (100 mW cm(-2)), which is by far the highest efficiency among the reported inorganic quantum dot sensitizers.
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Titanium nitride thin film as a novel charge collector in TCO-less dye-Sensitized Solar Cell
Journal of Materials Chemistry, 2011Co-Authors: Beomjin Yoo, Kang Jin Kim, Yong Hyun Kim, Won Mok Kim, Kyungkon Kim, Min Jae Ko, Nam Gyu ParkAbstract:A titanium nitride (TiN)-based dye-Sensitized Solar Cell is developed where TiN is used as a charge collector and TCO-less glass as a substrate. A nanocryst. TiO2 film was deposited onto a TCO-less glass substrate using the radio-frequency magnetron sputtering method and capped with a TiN film with a thickness of ∼66 to ∼167 nm, which was controlled by varying sputtering time. The crystal structure of TiN layers is analyzed using x-ray diffraction, chem. bonding nature and compn. (TiN0.95) were confirmed by XPS and Rutherford backscattering spectroscopy, resp. Cross-sectional scanning electron microscopic images confirmed the columnar structure of TiN films. Elec. resistance exponentially decayed and approached 4.4 Ω as the TiN film thickness increased up to 167 nm. The photovoltaic property is significantly influenced by the TiN film thickness. The energy conversion efficiency increases from 3.3% to 6.8% with increasing the TiN film thickness from 66 nm to 86 nm, where an increase in fill factor from 0.33 to 0.64 is mainly responsible for the efficiency improvement. The highest efficiency of 7.4% is obtained with a 136 nm-thick TiN film and declines to 5.8% at 167 nm, resulting in a one order of magnitude retarded diffusion rate of I3-. A long-term stability test was performed for 1000 h and compared with a Cell with pure Ti metal. The TiN-based Cell maintains an efficiency of 84% after 1000 h, while the efficiency of the Ti-based Cell is degraded by ∼34%, indicating that TiN is more stable than Ti in the TCO-less dye-Sensitized Solar Cell. [on SciFinder(R)]
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Light management in dye-Sensitized Solar Cell
Korean Journal of Chemical Engineering, 2010Co-Authors: Nam Gyu ParkAbstract:Dye-Sensitized Solar Cell (DSSC) is composed of a nanocrystalline TiO_2 film whose surface is covered with dye molecules, an iodide/tri-iodide electrolyte and a platinum counter electrode. Charge generation occurs when dye absorbs photon energy, which is separated by injection of photo-excited electrons into the conduction band of TiO_2. The photo-injected electrons are transported through TiO_2 network and collected at transparent conducting electrode. The oxidized dyes are regenerated by oxidation of iodide. Light-to-electricity conversion efficiency depends on photocurrent density, open-circuit voltage and fill factor. Photocurrent density is related to the incident photon-to-current conversion efficiency (IPCE) that is a collective measure of light harvesting, charge separation and charge collection efficiency. Since the higher IPCE, the higher photocurrent density becomes, light management in DSSC is one of most important issues. In this paper, effective methods to improve IPCE are described including size-dependent light scattering effect, bi-functionality design in material synthesis and panchromatic approach such as selective position of different dyes in a mesoporous TiO_2 film.
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size dependent scattering efficiency in dye Sensitized Solar Cell
Inorganica Chimica Acta, 2008Co-Authors: Jihee Park, Nam Gyu ParkAbstract:Abstract Effect of scattering particle size on light scattering efficiency in dye-Sensitized Solar Cell has been investigated with a FTO/semitransparent nano-TiO 2 layer (main-layer)/scattering layer (overlayer) structure, where two different rutile TiO 2 particles of 0.3 μm (G1) and 0.5 μm (G2) were used for a scattering overlayer and 20-nm anatase particle for nano-TiO 2 main-layer. The conversion efficiency of 7.55% for the 7 μm-thick main-layer film is improved to 8.94% and 8.78% when G1 and G2 particulate overlayers are introduced, respectively, corresponding to 18.4% and 16.3% increments. While the conversion efficiency of the 14 μm-thick main-layer is slightly improved from 8.60% to 9.09% and 9.15% upon depositing G1 and G2 particulate overlayers, respectively. Significant improvement and strong size-dependence upon deposition of scattering overlayer on the relatively thinner TiO 2 main-layer film are associated with the quantity and wavelength of transmitted light and the difference in reflectivity of G1 and G2 scattering particles.
Michael Gratzel - One of the best experts on this subject based on the ideXlab platform.
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facile preparation of large aspect ratio ellipsoidal anatase tio2 nanoparticles and their application to dye Sensitized Solar Cell
Electrochemistry Communications, 2009Co-Authors: Michael Gratzel, In Chan Baek, Muga Vithal, Jeong Ah Chang, Md K Nazeeruddin, Yongchae Chung, Sang Il SeokAbstract:A simple one-step heat-treatment of peroxotitanate complex aqueous solution at around 100 degrees C was resulted in the formation of ellipsoidal anatase TiO2 nanoparticles having a high aspect ratio with no branches. The length of these ellipsoidal TiO2 falls in the range of 200-350 nm, depending on mole ratio of Ti4+/H2O2. Dye-Sensitized Solar Cell based on these ellipsoidal nanocrystalline TiO2 as photoanode was fabricated and characterized. (C) 2009 Elsevier B.V. All rights reserved.
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nanocrystalline dye Sensitized Solar Cell copper indium gallium selenide thin film tandem showing greater than 15 conversion efficiency
Applied Physics Letters, 2006Co-Authors: Paul Liska, Michael Gratzel, K R Thampi, David Bremaud, D Rudmann, H M Upadhyaya, A N TiwariAbstract:Multijunction stacked (tandem) Solar Cells can increase the overall photovoltaic conversion efficiency by optimal utilization of the Solar spectrum in individual Cells. We demonstrate that a photovoltaic tandem Cell comprising a nanocrystalline dye-Sensitized Solar Cell as a top Cell for high-energy photons and a copper indium gallium selenide thin-film bottom Cell for lower-energy photons produces AM 1.5 Solar to electric conversion efficiencies greater than 15%.
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stable 8 efficient nanocrystalline dye Sensitized Solar Cell based on an electrolyte of low volatility
Applied Physics Letters, 2005Co-Authors: Peng Wang, Shaik M Zakeeruddin, Cedric Klein, Robin Humphrybaker, Michael GratzelAbstract:We demonstrate a ⩾8% efficient nanocrystalline dye-Sensitized Solar Cell retaining over 98% of its initial performance after 1000 h of accelerated tests subjected to thermal stress at 80 °C in the dark. Device degradation was also negligible following 1000 h of visible light soaking at 60 °C. This high performance and stable device was realized by using a robust electrolyte of low volatility in conjunction with the amphiphilic ruthenium sensitizer [Ru(4,4′-dicarboxylic acid-2,2′-bipyridine)(4,4′-bis(p-hexyloxystyryl)-2,2′-bipyridine)(NCS)2], coded as K-19, which was grafted together with 1-decylphosphonic acid on the mesoporous titania film acting as photoanode.We demonstrate a ⩾8% efficient nanocrystalline dye-Sensitized Solar Cell retaining over 98% of its initial performance after 1000 h of accelerated tests subjected to thermal stress at 80 °C in the dark. Device degradation was also negligible following 1000 h of visible light soaking at 60 °C. This high performance and stable device was realized by using a robust electrolyte of low volatility in conjunction with the amphiphilic ruthenium sensitizer [Ru(4,4′-dicarboxylic acid-2,2′-bipyridine)(4,4′-bis(p-hexyloxystyryl)-2,2′-bipyridine)(NCS)2], coded as K-19, which was grafted together with 1-decylphosphonic acid on the mesoporous titania film acting as photoanode.
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a stable quasi solid state dye Sensitized Solar Cell with an amphiphilic ruthenium sensitizer and polymer gel electrolyte
Nature Materials, 2003Co-Authors: Peng Wang, Shaik M Zakeeruddin, Jacquese Moser, Mohammad Khaja Nazeeruddin, Takashi Sekiguchi, Michael GratzelAbstract:A stable quasi-solid-state dye-Sensitized Solar Cell with an amphiphilic ruthenium sensitizer and polymer gel electrolyte
Madhuchhanda Choudhury - One of the best experts on this subject based on the ideXlab platform.
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Effect of Mn Doping on Multilayer PbS Quantum Dots Sensitized Solar Cell
IEEE Journal of Photovoltaics, 2018Co-Authors: Abhigyan Ganguly, Siddhartha Sankar Nath, Madhuchhanda ChoudhuryAbstract:The effect of Mn-ion doping on the device performance of multilayer PbS quantum dot (QD) Sensitized Solar Cells is investigated. Undoped as well as the doped PbS QDs, with different doping concentration, are synthesized using simple chemical methods on poly-vinyl alcohol matrix. QDs are characterized using ultraviolet visible spectroscopy, x-ray diffraction analysis, high-resolution transmission electron microscopy, energy dispersive x-ray, and photoluminescence spectroscopy. The QDs were introduced as sensitizer in ZnO-based Solar Cells in single as well as multiple layers. The current density vs. voltage characteristics are obtained for different Mn doping concentrations as well as for multiple numbers of QD layers, under artificial illumination. Enhanced photo-conversion efficiency was observed in multiple layered doped PbS QDs Sensitized Solar Cell compared to undoped QDs Sensitized Solar Cell.
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Enhanced Efficiency in Swift Heavy Ion Irradiated CdS Quantum Dots Sensitized Solar Cell
IEEE Photonics Technology Letters, 2018Co-Authors: Abhigyan Ganguly, Siddhartha Sankar Nath, Madhuchhanda ChoudhuryAbstract:The influence of high energy ion beam [swift heavy ion (SHI)] on CdS quantum dots that are used as a sensitizer in a Solar Cell is studied in this letter. A 100-MeV copper ion beam is selected for irradiation experiment with doses of 1 × 1011 and 3 × 1011 ions/cm2. With an increase in the dose, the optical absorption edge of irradiated quantum dots reveals a little red shift with respect to that of unirradiated (pristine) ones. The irradiated quantum dots are introduced as a sensitizer on a ZnO photoelectrode Solar Cell. An increase in the current density is observed for irradiated samples at a lower dose, while at a higher dose, the current density decreases. In addition, the other parameters, like open circuit voltage, fill factor, and photoconversion efficiency, are also reported for the SHI-irradiated quantum dot Sensitized Solar Cell.
Yuan Feng Ke - One of the best experts on this subject based on the ideXlab platform.
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surface plasmon resonance of layer by layer gold nanoparticles induced photoelectric current in environmentally friendly plasmon Sensitized Solar Cell
Light-Science & Applications, 2012Co-Authors: Yen Hsun Su, Yuan Feng Ke, Shi Liang Cai, Qian Yu YaoAbstract:The efficiency of a plasmon-Sensitized Solar Cell can be improved by depositing gold nanoparticles on the Cell’s surface. Achieving a high energy-conversion efficiency—the percentage of incident Solar energy converted into electrical energy—is the primary goal for any Solar Cell technology. Yen-Hsun Su and colleagues at National Dong Hwa University in Hualien have now demonstrated that depositing multiple layers of gold nanoparticles on the surface of a plasmon-Sensitized Solar Cell increases the amount of light scattered across its surface, boosting the amount of light absorbed and thus improving its efficiency. Once optimized, such gold-covered plasmonic Solar Cells have the potential to replace the more popular dye-Sensitized Solar Cells.
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Surface plasmon resonance of layer-by-layer gold nanoparticles induced photoelectric current in environmentally-friendly plasmon-Sensitized Solar Cell
Light: Science & Applications, 2012Co-Authors: Yen Hsun Su, Yuan Feng KeAbstract:The efficiency of a plasmon-Sensitized Solar Cell can be improved by depositing gold nanoparticles on the Cell’s surface. Achieving a high energy-conversion efficiency—the percentage of incident Solar energy converted into electrical energy—is the primary goal for any Solar Cell technology. Yen-Hsun Su and colleagues at National Dong Hwa University in Hualien have now demonstrated that depositing multiple layers of gold nanoparticles on the surface of a plasmon-Sensitized Solar Cell increases the amount of light scattered across its surface, boosting the amount of light absorbed and thus improving its efficiency. Once optimized, such gold-covered plasmonic Solar Cells have the potential to replace the more popular dye-Sensitized Solar Cells. Layer-by-layer gold nanoparticles are used to generate photocurrent in an environmentally-friendly plasmon-Sensitized Solar Cell towing to surface plasmon resonance. The efficiency of the photoelectric conversion of gold nanoparticle layers is increased as the intensity of surface plasmon resonance increases. We also explain the experimental results by modeling the phenomenon of charge separation and photocurrent formation, and the relationship between surface plasmon resonance and photocurrent formation, which has potential application in plasmon-Sensitized Solar Cells and plasmonic Solar Cells in the future.
Yen Hsun Su - One of the best experts on this subject based on the ideXlab platform.
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surface plasmon resonance of layer by layer gold nanoparticles induced photoelectric current in environmentally friendly plasmon Sensitized Solar Cell
Light-Science & Applications, 2012Co-Authors: Yen Hsun Su, Yuan Feng Ke, Shi Liang Cai, Qian Yu YaoAbstract:The efficiency of a plasmon-Sensitized Solar Cell can be improved by depositing gold nanoparticles on the Cell’s surface. Achieving a high energy-conversion efficiency—the percentage of incident Solar energy converted into electrical energy—is the primary goal for any Solar Cell technology. Yen-Hsun Su and colleagues at National Dong Hwa University in Hualien have now demonstrated that depositing multiple layers of gold nanoparticles on the surface of a plasmon-Sensitized Solar Cell increases the amount of light scattered across its surface, boosting the amount of light absorbed and thus improving its efficiency. Once optimized, such gold-covered plasmonic Solar Cells have the potential to replace the more popular dye-Sensitized Solar Cells.
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Surface plasmon resonance of layer-by-layer gold nanoparticles induced photoelectric current in environmentally-friendly plasmon-Sensitized Solar Cell
Light: Science & Applications, 2012Co-Authors: Yen Hsun Su, Yuan Feng KeAbstract:The efficiency of a plasmon-Sensitized Solar Cell can be improved by depositing gold nanoparticles on the Cell’s surface. Achieving a high energy-conversion efficiency—the percentage of incident Solar energy converted into electrical energy—is the primary goal for any Solar Cell technology. Yen-Hsun Su and colleagues at National Dong Hwa University in Hualien have now demonstrated that depositing multiple layers of gold nanoparticles on the surface of a plasmon-Sensitized Solar Cell increases the amount of light scattered across its surface, boosting the amount of light absorbed and thus improving its efficiency. Once optimized, such gold-covered plasmonic Solar Cells have the potential to replace the more popular dye-Sensitized Solar Cells. Layer-by-layer gold nanoparticles are used to generate photocurrent in an environmentally-friendly plasmon-Sensitized Solar Cell towing to surface plasmon resonance. The efficiency of the photoelectric conversion of gold nanoparticle layers is increased as the intensity of surface plasmon resonance increases. We also explain the experimental results by modeling the phenomenon of charge separation and photocurrent formation, and the relationship between surface plasmon resonance and photocurrent formation, which has potential application in plasmon-Sensitized Solar Cells and plasmonic Solar Cells in the future.
