Morphology-dependent photocatalytic and gas-sensing functions of three-dimensional TiO2–ZnO nanoarchitectures

Nanocomposites consisting of three-dimensional ZnO nanorods-decorated TiO₂ nanorod templates (TiO₂–ZnO) have been prepared by combining sputtering and hydrothermal growth strategies.

Monolithic Two-Dimensional Photonic Crystal Reflectors for the Fabrication of Highly Efficient and Highly Transparent Dye-Sensitized Solar Cells

The transparent characteristic of dye-sensitized solar cells (DSCs) makes them suitable for building integrated photovoltaic (BIPV) devices. However, the diffusive scattering layer, which is usually used to increase the efficiency of these devices, greatly lowers the transparency of the DSC. This paper described a two-dimensional (2D) photonic crystal (PC) reflector with a sub-micrometer characteristic length that can improve the efficiency of these devices while maintaining transparency. This 2D PCs were fabricated directly onto TiO₂ photoelectrodes using colloidal lithography and have the structure of a nanopillar array. A nanopillar with a height of 430 nm was observed to selectively reflect up to 40% of the light of 400-500 nm wavelength. The perceived transparency of the 2D PC electrode was 52%, which is much higher than 0.3% of the conventional scattering layer. The DSC fabricated using the 2D PC electrode demonstrated a maximum photon-to-electric conversion efficiency of 8.23%, which is 18% higher than the pristine electrode. The 2D PC is a highly efficient and wavelength-selective reflector that can be applied to various photoelectric conversion devices.

Improved Photoelectrochemical Cell Performance of Tin Oxide with Functionalized Multiwalled Carbon Nanotubes-Cadmium Selenide Sensitizer

Here we report functionalized multiwalled carbon nanotubes (f-MWCNTs)-CdSe nanocrystals (NCs) as photosensitizer in photoelectrochemical cells, where f-MWCNTs were uniformly coated with CdSe NCs onto SnO2 upright standing nanosheets by using a simple electrodeposition method. The resultant blended photoanodes demonstrate extraordinary electrochemical properties including higher Stern-Volmer constant, higher absorbance, and positive quenching, etc., caused by more accessibility of CdSe NCs compared with pristine SnO2-CdSe photoanode. Atomic and weight percent changes of carbon with f-MWCNTs blending concentrations were confirmed from the energy dispersive X-ray analysis. The morphology images show a uniform coverage of CdSe NCs over f-MWCNTs forming a core-shell type structure as a blend. Compared to pristine CdSe, photoanode with f-MWCNTs demonstrated a 257% increase in overall power conversion efficiency. Obtained results were corroborated by the electrochemical impedance analysis. Higher scattering, more accessibility, and hierarchical structure of SnO2-f-MWCNTs-blend-CdSe NCs photoanode is responsible for higher (a) electron mobility (6.89 × 10(-4) to 10.89 × 10(-4) cm(2) V(-1) S(1-)), (b) diffusion length (27 × 10(-6)),

Significant enhancement of power conversion efficiency for dye sensitized solar cell using 1D/3D network nanostructures as photoanodes

The single-crystalline TiO2 nanorod arrays with rutile phase have attracted much attention in the dye sensitized solar cells (DSSCs) applications because of their superior chemical stability, better electron transport properties, higher refractive index and low production cost. However, it suffers from a low surface area as compared with TiO2 nanoparticle films. In order to enlarge the surface area of TiO2 nanorod arrays, the 1D nanorods/3D nanotubes sample was synthesized using a facile two-step hydrothermal process involving hydrothermal growth 1D/3D nanorods and followed by post-etching treatment. In such bi-layer structure, the oriented TiO2 nanorods layer could provide direct pathway for fast electron transportation, and the 3D nanotubes layer offers a higher surface area for dye loading, therefore, the 1D nanorods/3D nanotubes photoanode exhibited faster electron transport and higher surface area than either 1D or 3D nanostructures alone, and an highest efficiency of 7.68% was achieved for the DSSCs based on 1D nanorods/3D nanotubes photoanode with further TiCl4 treatment.

Optimizing the prepared condition of TiO2 1D/3D network structure films to enhance the efficiency of dye-sensitized solar cells

TiO₂ films with 1D/3D network structures have been prepared via two-step hydrothermal method and applied in DSSCs, an high efficiency of 7.68% was achieved.

Simplistic construction of cadmium sulfoselenide thin films via a hybrid chemical process for enhanced photoelectrochemical performance

Hybrid APT method, novel custard apple-like cadmium sulfoselenide thin films, nanocrystalline pure phase, highest power conversion efficiency of 1.02%.

Evaluation of a metal free dye for efficient dye sensitized solar cells based on hydrothermally synthesized TiO2 nanoflowers

Hierarchical TiO₂ nanoflowers for DN350 organic dye sensitized solar cells.

Enhanced dye-sensitized solar cells performance using anatase TiO2 mesocrystals with the Wulff construction of nearly 100% exposed {101} facets as effective light scattering layer

Anatase TiO2 mesocrystals with a Wulff construction of nearly 100% exposed {101} facets were successfully synthesized by a facile, green solvothermal method. Their morphology, and crystal structure are characterized by powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Accordingly, a possible growth mechanism of anatase TiO2 mesocrystals is elucidated in this work. The as-prepared single anatase TiO2 mesocrystal's mean center diameter is about 500 nm, and the length is about 1 μm. They exhibit high light adsorbance, high reflectance and low transmittance in the visible region due to the unique nearly 100% exposed {101} facets. When utilized as the scattering layer in dye-sensitized solar cells (DSSCs), such mesocrystals effectively enhanced light harvesting and led to an increase of the photocurrent of the DSSCs. As a result, by using an anatase TiO2 mesocrystal film as a scattering overlayer of a compact commercial P25 TiO2 nanoparticle film, the double layered DSSCs show a power conversion efficiency of 7.23%, indicating a great improvement compared to the DSSCs based on a P25 film (5.39%) and anatase TiO2 mesocrystal films, respectively. The synergetic effect of P25 and the mesocrystals as well as the latters unique feature of a Wulff construction of nearly 100% exposed (101) facets are probably responsible for the enhanced photoelectrical performance. In particular, we explore the possibility of the low surface area and exposed {101} facets as an efficient light scattering layer of DSSCs. Our work suggests that anatase TiO2 mesocrystals with the Wulff construction is a promising candidate as a superior scattering material for high-performance DSSCs.

Synthesis of micrometer-sized hierarchical rutile TiO2flowers and their application in dye sensitized solar cells

Morphologically advantageous hierarchical TiO₂architectures such as cactus-like flowers, and highly branched TiO₂nanorods were synthesized and tested as DSSC photoanodes.

Single step hydrothermal synthesis of hierarchical TiO2 microflowers with radially assembled nanorods for enhanced photovoltaic performance

Herein, 3D hierarchical TiO₂ microflowers with a well faceted profile and high crystallinity were successfully obtained via a surfactant directed single step facile hydrothermal technique.

Surfactant free most probable TiO₂ nanostructures via hydrothermal and its dye sensitized solar cell properties

Tailoring the nano-morphology and nano-architecture of titanium dioxide (TiO₂) is the most important task in the third generation solar cells (Dye sensitized solar cells/Quantum dot sensitized solar cells) (DSSCs/QDSSCs). In this article we present complete study of surfactant free synthesis of TiO₂ nanostructures by a simple and promising hydrothermal route. The plethora of nanostructures like nanoparticles clusters, 1D tetragonal nanorods, 3D dendrites containing nanorods having <30 nm diameter and 3D hollow urchin like have been synthesized. These nanostructures possess effective large surface area and thus useful in DSSCs. In the present work, 7.16% power conversion efficiency has been demonstrated for 3D dendritic hollow urchin like morphology. Our synthetic strategy provides an effective solution for surfactant free synthesis of efficient TiO₂ nanoarchitectures.