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Sang-Hoon Kim

Bio: Sang-Hoon Kim is an academic researcher from Samsung. The author has contributed to research in topics: Lithium battery & Layer (electronics). The author has an hindex of 12, co-authored 64 publications receiving 1081 citations. Previous affiliations of Sang-Hoon Kim include Ulsan National Institute of Science and Technology & Korea National University of Education.


Papers
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Journal ArticleDOI
TL;DR: This work presents a solid-state solar cell design, consisting of TiO(2) nanotube arrays vertically oriented from the FTO-coated glass substrate, sensitized with unsymmetrical squaraine dye (SQ-1) that absorbs in the red and NIR portion of solar spectrum, and which are uniformly infiltrated with p-type regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT
Abstract: The development of high-efficiency solid-state excitonic photovoltaic solar cells compatible with solution processing techniques is a research area of intense interest, with the poor optical harvesting in the red and near-IR (NIR) portion of the solar spectrum a significant limitation to device performance. Herein we present a solid-state solar cell design, consisting of TiO(2) nanotube arrays vertically oriented from the FTO-coated glass substrate, sensitized with unsymmetrical squaraine dye (SQ-1) that absorbs in the red and NIR portion of solar spectrum, and which are uniformly infiltrated with p-type regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) that absorbs higher energy photons. Our solid-state solar cells exhibit broad, near-UV to NIR, spectral response with external quantum yields of up to 65%. Under UV filtered AM 1.5G of 90 mW/cm(2) intensity we achieve typical device photoconversion efficiencies of 3.2%, with champion device efficiencies of 3.8%.

272 citations

Journal ArticleDOI
TL;DR: This work considers the development of the various nanotube array synthesis techniques, different applications of the TiO(2) nanotubes, unresolved issues, and possible future research directions.
Abstract: Highly ordered vertically oriented TiO2 nanotube arrays fabricated by electrochemical anodization offer a large surface area architecture with precisely controllable nanoscale features. These nanotubes have shown remarkable properties in a variety of applications including, for example, their use as hydrogen sensors, in the photoelectrochemical generation of hydrogen, dye-sensitized and solid-state heterojunction solar cells, photocatalytic reduction of carbon dioxide into hydrocarbons, and as a novel drug delivery platform. Herein we consider the development of the various nanotube array synthesis techniques, different applications of the TiO2 nanotube arrays, unresolved issues, and possible future research directions.

245 citations

Journal ArticleDOI
TL;DR: A significant enhancement in the light harvesting and photocurrent generation of SS-DSCs due to Förster resonance energy transfer (FRET) is demonstrated.
Abstract: Solid-state dye-sensitized solar cells (SS-DSCs) offer the potential to make low cost solar power a reality, however their photoconversion efficiency must first be increased. The dyes used are commonly narrow band with high absorption coefficients, while conventional photovoltaic operation requires proper band edge alignment significantly limiting the dyes and charge transporting materials that can be used in combination. We demonstrate a significant enhancement in the light harvesting and photocurrent generation of SS-DSCs due to Forster resonance energy transfer (FRET). TiO(2) nanotube array films are sensitized with red/near IR absorbing SQ-1 acceptor dye, subsequently intercalated with Spiro-OMeTAD blended with a visible light absorbing DCM-pyran donor dye. The calculated Forster radius is 6.1 nm. The donor molecules contribute a FRET-based maximum IPCE of 25% with a corresponding excitation transfer efficiency of approximately 67.5%.

119 citations

Journal ArticleDOI
TL;DR: Three organic sensitizers containing bis-dimethylfluorenyl amino donor and a cyanoacrylic acid acceptor bridged by p-phenylene vinylene unit were synthesized and the maximum power conversion efficiency of JK-59 reached 7.02%.
Abstract: Three organic sensitizers containing bis-dimethylfluorenyl amino donor and a cyanoacrylic acid acceptor bridged by p-phenylene vinylene unit were synthesized. The power conversion efficiency was quite sensitive to the length of bridged phenylene vinylene groups. A nanocrystalline TiO2 dye-sensitized solar cell was fabricated using three sensitizers. The maximum power conversion efficiency of JK-59 reached 7.02%.

113 citations

Journal ArticleDOI
17 Aug 2010-Langmuir
TL;DR: The functionalized unsymmetrical benzothiazole squaraine organic sensitizers designed and developed to observe an intense and wider absorption band in the red/NIR wavelength region are demonstrated.
Abstract: The functionalized unsymmetrical benzothiazole squaraine organic sensitizers 5-carboxy-2-({3-[(3-hexylbenzothiazol-2(3H)-ylidene)methyl]-2-hydroxy-4-oxo-2-cyclobuten-1-ylidene}methyl)-1-hexyl-3,3-dimethyl-3H-indolium (hereafter named as SK-11) and 5-carboxy-2-({3-[(3-hexyl-5-methoxybenzothiazol-2(3H)-ylidene)methyl]-2-hydroxy-4-oxo-2-cyclobuten-1-ylidene}methyl)-1-hexyl-3,3-dimethyl-3H-indolium (coded as SK-12) are designed and developed to observe an intense and wider absorption band in the red/NIR wavelength region. DFT/TDDFT calculations have been performed on the two unsymmetrical squaraine sensitizers to gain insight into their electronic and optical properties. The utility of these dyes in solid state dye sensitized solar cells (SS-DSSCs) is demonstrated.

42 citations


Cited by
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Journal ArticleDOI
TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

8,707 citations

Journal ArticleDOI
TL;DR: Recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells are focused on.
Abstract: Dye-sensitized solar cells (DSSC) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy This Review focuses on recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells Special attention has been paid to the design principles of these dyes and on the effect of various electrolyte systems Cosensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device In addition, we report on inverted dyes for photocathodes, which constitutes a relatively new approach for the production of tandem cells Special consideration has been paid to the correlation between the molecular structure and physical properties to their performance in DSSCs

2,549 citations

Journal ArticleDOI
TL;DR: In this article, the perovskite CH3NH3PbX3 (X = Cl, Br, or I) sensitizer made a breakthrough in solid-state mescoscopic solar cells, where the first record efficiency of around 10% was reported in 2012 using submicrometer-thick TiO2 film sensitized with CH 3NH3pbI3. A rapid increase in efficiency approaching 14% followed shortly.
Abstract: Recently, perovskite CH3NH3PbI3 sensitizer has attracted great attention due to its superb light-harvesting characteristics. Organometallic or organic materials were mostly used as sensitizers for solid-state dye-sensitized solar cells at early stages. Inorganic nanocrystals have lately received attention as light harvesters due to their high light-absorbing properties. Metal chalcogenides have been investigated with solid-state dye-sensitized solar cells; however, the best power conversion efficiency was reported to be around 6%. CH3NH3PbX3 (X = Cl, Br, or I) perovskite sensitizer made a breakthrough in solid-state mescoscopic solar cells, where the first record efficiency of around 10% was reported in 2012 using submicrometer-thick TiO2 film sensitized with CH3NH3PbI3. A rapid increase in efficiency approaching 14% followed shortly. In this Perspective, recent progress in perovskite-sensitized solid-state mesoscopic solar cells is reviewed. On the basis of the recent achievements, a power conversion eff...

1,275 citations

Journal ArticleDOI
TL;DR: O'Regan and Gratzel demonstrated that a film of titania nanoparticles deposited on a DSC would act as a mesoporous n-type photoanode and thereby increase the available surface area for dye attachment by a factor of more than a thousand.
Abstract: Dye-sensitized solar cells (DSCs) are attractive because they are made from cheap materials that do not need to be highly purified and can be printed at low cost 1 . DSCs are unique compared with almost all other kinds of solar cells in that electron transport, light absorption and hole transport are each handled by different materials in the cell 2,3 . The sensitizing dye in a DSC is anchored to a wide-bandgap semiconductor such as TiO2, SnO2 or ZnO. When the dye absorbs light, the photoexcited electron rapidly transfers to the conduction band of the semiconductor, which carries the electron to one of the electrodes 4 . A redox couple, usually comprised of iodide/triiodide (I – /I3 – ), then reduces the oxidized dye back to its neutral state and transports the positive charge to the platinized counter-electrode 5 . In 1991, O’Regan and Gratzel demonstrated that a film of titania (TiO2) nanoparticles deposited on a DSC would act as a mesoporous n-type photoanode and thereby increase the available surface area for dye attachment by a factor of more than a thousand 1 . This approach dramatically improved light absorption and brought power-conversion efficiencies into a range that allowed the DSC to be viewed as a serious competitor to other solar cell technologies 6 . A schematic and energy level diagram showing the operation of a typical DSC is shown in Fig. 1. During the 1990s and the early 2000s, researchers found that organometallic complexes based on ruthenium provided the highest power-conversion efficiencies 7,8

1,215 citations

Journal ArticleDOI
TL;DR: The cell performance of the arieslamine organic dyes are compared, providing a comprehensive overview of arylamineorganic dyes, demonstrating the advantages/disadvantages of each class, and pointing out the field that needs to reinforce the research direction in the further application of DSCs.
Abstract: Arylamine organic dyes with donor (D), π-bridge (π) and acceptor (A) moieties for dye-sensitized solar cells (DSCs) have received great attention in the last decade because of their high molar absorption coefficient, low cost and structural variety. In the early stages, the efficiency of DSCs with arylamine organic dyes with D–π–A character was far behind that of DSCs with ruthenium(II) complexes partly due to the lack of information about the relationship between the chemical structures and the photovoltaic performance. However, exciting progress has been recently made, and power conversion efficiencies over 10% were obtained for DSCs with arylamine organic dyes. It is thus that the recent research and development in the field of arylamine organic dyes employing an iodide/triiodide redox couple or polypyridyl cobalt redox shuttles as the electrolytes for either DSCs or solid-state DSCs has been summarized. The cell performance of the arylamine organic dyes are compared, providing a comprehensive overview of arylamine organic dyes, demonstrating the advantages/disadvantages of each class, and pointing out the field that needs to reinforce the research direction in the further application of DSCs.

970 citations