The Experts below are selected from a list of 19899 Experts worldwide ranked by ideXlab platform
S Uchida - One of the best experts on this subject based on the ideXlab platform.
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spray deposition of electrospun tio2 Nanorods for dye sensitized solar cell
Nanotechnology, 2007Co-Authors: K Fujihara, Abhishek Kumar, Rajan Jose, Seeram Ramakrishna, S UchidaAbstract:A simple technique was developed to fabricate a large-area TiO2 electrode layer using electrospun Nanorods for dye-sensitized solar cells (DSSCs). Using this technique, we assembled DSSCs of area ~1 cm2 consisting of a thin TiO2 nanoparticle layer and a thick TiO2 Nanorod layer as electrode. The TiO2 Nanorods were obtained by mechanically grinding electrospun TiO2 nanofibers. A titania sol was first spin-coated on a conductive glass plate and a TiO2 Nanorod layer was next spray dried on it to fabricate TiO2 nanoparticle/Nanorod layers. These layers were subsequently sintered. The best-performing DSSC evaluated under AM1.5G (1 sun) condition gave current density ~13.6 mA cm−2, open circuit voltage ~0.8 V, fill factor ~51% and energy conversion efficiency ~5.8%.
Yiping Zhao - One of the best experts on this subject based on the ideXlab platform.
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engineering a well aligned composition graded cusi Nanorod array by an oblique angle codeposition technique
Crystal Growth & Design, 2010Co-Authors: Yuping He, Yiping ZhaoAbstract:A well-aligned composition-graded CuSi Nanorod array structure has been fabricated by a simple oblique angle codeposition technique in a physical vapor deposition system. The Cu and Si graded composition distribution in the Nanorods was confirmed by their elemental mapping and depth profiles. The crystal structure evolution with the Nanorod length was revealed by both electron and X-ray diffractions. The size evolution of the CuSi Nanorods followed a power law, which results from the combination effects of geometric shadowing and limited surface atomic diffusion. Such a graded composition distribution could relax the stress between the Nanorods and the substrate, and is promising for applications where improved Nanorod−substrate adhesion is required.
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absorbance spectra of aligned ag Nanorod arrays prepared by oblique angle deposition
Journal of Applied Physics, 2006Co-Authors: Yiping Zhao, Stephen B Chaney, Z Y ZhangAbstract:The s- and p-polarization absorbance spectra of Ag Nanorod arrays with different heights prepared by oblique angle deposition are studied in detail. For short Nanorods, both s- and p-polarization spectra, are dominated by a similar and single resonant peak. For long Nanorods, a sharp UV peak dominates the s-polarization spectrum, while a broad vis–near infrared peak dominates the p-polarization spectrum. Three different absorbance peaks located at 293, 360, and 420–720nm, respectively, have been observed and evolve differently for s- and p-polarization absorbances with the Nanorod height. The change of the absorbance as a function of the Nanorod height is a reflection of the growth dynamics of the Nanorod. The discrete dipole approximation was used to calculate the extinction spectra of Ag Nanorod with 80-nm-diameter and different lengths, and the calculated results are qualitatively consistent with the experimental results.
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polarized surface enhanced raman and absorbance spectra of aligned silver Nanorod arrays
Journal of Physical Chemistry B, 2006Co-Authors: Yiping Zhao, Stephen B Chaney, Saratchandra Shanmukh, Richard A DluhyAbstract:Polarized surface-enhanced Raman scattering (SERS) and UV-vis absorbance spectra were measured for a nonplanar Ag Nanorod array substrate prepared by oblique angle vapor deposition. The anisotropy of the SERS polarization was shown to differ from that of the polarized UV-vis absorbance. The maximum SERS intensity was observed in the polarization direction perpendicular to the long axis of the Ag Nanorods, while the UV-vis absorbance was strongly polarized along the direction of the long axis of the Nanorod array. Analysis of the polarization data showed that molecular orientation was not the cause of the anisotropic SERS scattering. Rather, the SERS anisotropy was primarily attributed to the lateral arrangement of the three-dimensional tilted Nanorod lattice in which highly localized plasmon modes are created by strong electromagnetic coupling between adjacent metallic Nanorods.
Hui-seon Kim - One of the best experts on this subject based on the ideXlab platform.
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Effects of Seed Layer on Growth of ZnO Nanorod and Performance of Perovskite Solar Cell
The Journal of Physical Chemistry C, 2015Co-Authors: Dae-yong Son, Kyeong-hui Bae, Hui-seon Kim, N. G. ParkAbstract:Effects of seed layer on growth of ZnO Nanorod and photovoltaic performance of perovskite solar cell were investigated. Three different coating solutions (the clear solution, the colloidal solution, and the nano-powder dispersed solution) were prepared for making seed layers. Vertically aligned ZnO Nanorods were grown on the colloidal-based seed layer, while tilted Nanorods were obtained on the solution- and powder-based seed layers. Open-circuit voltage (Voc) of the CH3NH3PbI3 perovskite solar cell was predominantly influenced by the seed layers, where highest Voc was obtained from the ZnO Nanorod grown on the colloidal seed layer. Impedance spectroscopic study revealed that recombination resistances at the seed layer contact and the ZnO Nanorod/perovskite interface were increased by the colloidal coating, which was responsible for the enhanced Voc. Surface modification of ZnO Nanorods improved further Voc and fill factor, leading to power conversion efficiency of 14.35%. This work emphasizes that the se...
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high efficiency solid state sensitized solar cell based on submicrometer rutile tio2 Nanorod and ch3nh3pbi3 perovskite sensitizer
Nano Letters, 2013Co-Authors: Hui-seon Kim, Jinwook Lee, Natalia Yantara, Pablo P Boix, Sneha A Kulkarni, Subodh Mhaisalkar, Michael Gratzel, Namgyu ParkAbstract:We report a highly efficient solar cell based on a submicrometer (∼0.6 μm) rutile TiO2 Nanorod sensitized with CH3NH3PbI3 perovskite nanodots. Rutile Nanorods were grown hydrothermally and their lengths were varied through the control of the reaction time. Infiltration of spiro-MeOTAD hole transport material into the perovskite-sensitized Nanorod films demonstrated photocurrent density of 15.6 mA/cm2, voltage of 955 mV, and fill factor of 0.63, leading to a power conversion efficiency (PCE) of 9.4% under the simulated AM 1.5G one sun illumination. Photovoltaic performance was significantly dependent on the length of the Nanorods, where both photocurrent and voltage decreased with increasing Nanorod lengths. A continuous drop of voltage with increasing Nanorod length correlated with charge generation efficiency rather than recombination kinetics with impedance spectroscopic characterization displaying similar recombination regardless of the Nanorod length.
Dong Young Kim - One of the best experts on this subject based on the ideXlab platform.
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charge transport characteristics of high efficiency dye sensitized solar cells based on electrospun tio2 Nanorod photoelectrodes
Journal of Physical Chemistry C, 2009Co-Authors: Byung Hong Lee, Mi Yeon Song, Sungyeon Jang, Seongyeop Kwak, Dong Young KimAbstract:In this report, dye-sensitized solar cells (DSSCs) with high energy conversion efficiencies were fabricated using TiO2 Nanorods electrospun from a solution mixture of titanium n-propoxide and poly(vinyl acetate) in dimethyl formamide. Investigation of the charge transport characteristics of this unique type of DSSC disclosed that the efficiency of the DSSCs was enhanced by optimizing the Nanorod morphology to facilitate charge transport. Our TiO2 Nanorods have an intrinsically higher sensitizer loading capability than conventional TiO2 nanoparticles and have much slower recombination lifetimes compared to conventional nanoparticles. Long electron lifetime in Nanorod electrode contributes to the enhanced effective photocarrier collection as well as the conversion efficiency. The electron transport behavior of Nanorod photoelectrodes was further improved by TiCl4 post-treatment. The post-treatment reduces the pore volume of Nanorod photoelectrodes while improving inter-rod connectivity and enhancing electro...
Guofeng Yang - One of the best experts on this subject based on the ideXlab platform.
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formation of Nanorod ingan gan multiple quantum wells using nickel nano masks and dry etching for ingan based light emitting diodes
Materials Science in Semiconductor Processing, 2015Co-Authors: Guofeng Yang, F Xie, Yuying Tong, Peng Chen, Dawei Yan, Junjun Xue, Huaxin Zhu, Ying Guo, Shumei GaoAbstract:Abstract In recent years, GaN-based Nanorods have attracted considerable interest for potential applications in electronic and optoelectronic devices due to the quantum confinement and strain relaxation effect. Although a host of technologies are emerging for the Nanorod structure growth and fabrication, a simple method using self-assembled Ni nano-masks and dry etch to form InGaN/GaN Nanorod multiple quantum wells (MQWs) has been developed. In this paper, we briefly review the previous developments of GaN-based Nanorods, then the particular technology for the fabrication of Nanorod InGaN/GaN MQWs using Ni nano-masks and dry etching has been introduced, and the formation of Ni nano-masks on GaN surface is discussed in detail. Furthermore, various structures of high efficient light emitting diodes (LEDs) based on this method are reviewed, the surface nano-roughed process for InGaN/GaN LEDs and Nanorod InGaN/GaN LEDs fabrication using Ni nano-masks have been presented.
