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29. Double layered nanoarchitecture based on anodic TiO2 nanotubes for dye-sensitized solar cells.

Author

Ahn, Bo-Eun, Kim, Hyun Sik, Yang, Si Kyung, Ahn, Kwang-Soon, and Kang, Soon Hyung

Subjects
*TITANIUM oxides, *TITANIUM nanotubes, *DYE-sensitized solar cells, *ELECTROCHEMICAL analysis, *ELECTRODES, *ELECTRON transport, *LIGHT scattering
Abstract

Abstract: Based on the TiO2 nanotube (TONT) with three different thicknesses (10, 18, 28μm) prepared by electrochemical anodization, a double layered electrode consisting of TONT and TiO2 nanoparticles (TONPs) with a size of approximately 20nm was developed. The anodic TONT electrode has been actively investigated due to its beneficial properties such as a favorable electron transport rate and light scattering ability. However, the small specific surface area caused by the large pores and vacant space between 1-D NTs impedes the fabrication of high efficient DSSCs. Hence, the TONP layer with a thickness of 10μm is additionally deposited on the top surface of the TONT film to offer a sufficient surface area for large dye loading. Compared to a single TONT electrode, the double layered TONT/NP electrodes provide a high short-circuit current density (J sc ) and fill factor (FF) while maintaining a constant open-circuit voltage (V oc ), finally disclosing a higher conversion efficiency (η), attributed to the high loading of dye molecules, light scattering ability, low resistance in the photoanode/electrolyte interface, and longer electron lifetimes. In particular, the optimal η was attained with the TONT/NP (18μm) electrode having a V oc of 0.80V, a J sc of 7.80mA/cm2, a FF of 62.7%, and a η of 3.93%. Incidentally, when using a longer TONT film (28μm), η decreases steadily due to the fast charge recombination process. A more detailed discussion is included below. [Copyright &y& Elsevier]

Published
2014
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30. Supramolecular alternating block copolymers via metal coordination.

Author

Yang SK, Ambade AV, and Weck M

Subjects
Alkenes chemistry, Magnetic Resonance Spectroscopy, Molecular Structure, Polymers chemistry, Chemistry, Organic methods, Polymers chemical synthesis, Ruthenium chemistry
Abstract

A bimetallic ruthenium olefin metathesis initiator was synthesized and used to polymerize functionalized norbornenes, affording polymers that are living at both polymer chain-ends. Using this bis-ruthenium initiator strategy and combining it with functional chain-terminators, highly-efficient syntheses of either SCS-Pd(II) pincer- or pyridine-functionalized symmetrical telechelic polymers were developed. The terminal functional group incorporation was confirmed by 1H NMR spectroscopy analyses. The telechelic polymers were self-assembled into block copolymers by means of metal coordination between corresponding terminal recognition units. The self-assembly process was monitored by 1H NMR spectroscopy revealing nearly quantitative functionalization. The resulting supramolecular block copolymers were further characterized by viscometry and dynamic light scattering.

Published
2009
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