Carbon fiber/Co9S8 nanotube arrays hybrid structures for flexible quantum dot-sensitized solar cells.

Recently, hybrid carbon materials and inorganic nanocrystals have received an intensive amount of attention and have opened up an exciting new field in the design and fabrication of high-performance catalysts. Here we present a novel kind of hybrid counter electrode (CE) consisting of a carbon fiber (CF) and Co9S8 nanotube arrays (NTs) for fiber-shaped flexible quantum dot-sensitized solar cells (QDSSCs). The growth mechanisms of Co(CO3)0.35Cl0.20(OH)1.10 nanowire arrays (NWs) on the CFs were discussed, and the catalytic activity of the CF, Pt and Co9S8/CF hybrid structure (Co9S8@CF) were elucidated systematically as well. An absolute energy conversion efficiency of 3.79% has been demonstrated under 100 mW cm(-2) AM 1.5 illumination by using Co9S8@CF as a CE. This work not only demonstrates an innovative approach for growing cobalt sulfide NTs on flexible substrates that can be applied in flexible devices for energy harvesting and storage, but also provides a kind of hybrid structure and high-efficiency CE for QDSSCs.

Facile and effective synthesis of hierarchical TiO2 spheres for efficient dye-sensitized solar cells.

Three-dimensional (3D) crystalline anatase TiO2 hierarchical spheres were successfully derived from Ti foils via a fast, template-free, low-temperature hydrothermal route followed by a calcination post-treatment. These dandelion-like TiO2 spheres are composed of numerous ultrathin nanoribbons, which were subsequently split into fragile nanoflakes as a result of the decomposition of Ti-complex intermediates to TiO2 and H2O at high temperature. The dye-sensitized solar cells (DSSCs) employing such hierarchically structured TiO2 spheres as the photoanodes exhibited a light-to-electricity conversion efficiency of 8.50%, yielding a 28% enhancement in comparison with that (6.64%) of P25-based DSSCs, which mainly benefited from the enhanced capacity of dye loading in combination with effective light scattering and trapping from hierarchical architecture.

Hierarchically structured nanotubes for highly efficient dye-sensitized solar cells.

Hierarchical TiO2 nanotube arrays grown on Ti foil are yielded by subjecting electrochemically anodized, vertically oriented TiO2 nanotube arrays to hydrothermal processing. The resulting DSSCs exhibit a significantly enhanced power conversion efficiency of 7.24%, which is a direct consequence of the synergy of higher dye loading, superior light-scattering ability, and fast electron transport.

Densely aligned rutile TiO2 nanorod arrays with high surface area for efficient dye-sensitized solar cells.

One-dimensional (1-D) TiO(2) nanorod arrays (NRAs) with large inner surface area are desired in dye-sensitized solar cells (DSSCs). So far, good performance of DSSCs based on 1-D rutile TiO(2) NRAs remains a challenge mainly owing to their low dye-loading ability resulting from the insufficient specific surface area of 1-D TiO(2) nanostructures. In this paper, densely aligned TiO(2) NRAs with tunable thickness were grown directly on transparent conductive fluorine-doped tin oxide (FTO) substrates by hydrothermal method, followed by a facile chemical etching route to further increase the specific surface area of the TiO(2) NRAs. The etching treatment leads to the split of TiO(2) nanorods into secondary nanorods with a reduced diameter, which markedly enlarges the inner surface area of the TiO(2) NRAs. The formation of 1-D rutile TiO(2) nanotube arrays (NTAs) is observed as well in the etched TiO(2) films. Finally, a DSSC efficiency of 5.94% was achieved by utilizing an etched TiO(2) NRA as the photoanode, which is so far the best DSSC efficiency that has been reported for the 1-D rutile TiO(2) NRA films.

Excited state structural dynamics and Herzberg-Teller coupling of tetraphenylporphine explored via resonance Raman spectroscopy and density functional theory calculation.

Resonance Raman spectra of free-base tetraphenylporphine (TPP) were obtained with 397.9, 416, and 435.7nm excitation wavelengths and density functional calculations were done to elucidate the electronic transitions and the resonance Raman spectra (RRs) of TPP. The RRs indicate that the Franck-Condon region photodynamics for S(0)-->S(4) electronic state is predominantly along the C(m)-ph stretch while that for S(0)-->S(3) electronic state is predominantly along the porphin ring C(beta)C(beta) stretch. Non-totally symmetric vibrational modes were regularly presented in resonance Raman spectra: the shorter the excitation wavelengths were, the stronger intensity the modes had, which can be interpreted in terms of electric dipole transition moments caused by Franck-Condon and Herzberg-Teller coupling. Four non-total symmetry vibrational mode upsilon(52,)upsilon(64), upsilon(97) and upsilon(130) in A(2) irreducible representative of TPP were observed in 397.9, 416 and 435.7nm resonance Raman spectrum. With the shorter wavelength laser excitations at 416 or 397.9nm, the A(2) vibrational modes show more enhanced Raman intensity by comparison with those in the TPP spectrum excited at 435.7nm.