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 ...

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Dye-Sensitized Solar Cells

Fabrication of thin film dye sensitized solar cells with solar to electric power conversion efficiency over 10

This review describes the main features of dye-sensitized solar cells (DSCs) and highlights recent breakthroughs in this promising thin-film photovoltaic (PV) technology. After a brief presentation of the commercially available technologies, the general operation principles and the most relevant characteristics of DSCs are summarized. Recent major advances in high efficiency sensitizers, nanostructured semiconductors and robust electrolytes offer an opportunity for DSCs integration into the marketplace. With attractive features, like low-cost potential, simple processing, wide range of applicability – from low-power electronics to semi-transparent windowpanes for electricity generation – and good performance under typical operating conditions, these cells are one step from large-scale commercialization. We describe major strategies that are under way to make DSCs a key technology in the future PV paradigm.

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Dye-sensitized solar cells: A safe bet for the future.

Twenty years after O’Regan and Gratzel’s seminal Nature paper entitled “A Low-Cost, High-Efficiency Solar-Cell Based on Dye-Sensitized Colloidal TiO2 Films”, dye-sensitized solar cells (DSCs) and analogous devices have become a major topic of research, with over 1000 papers published in 2010. Although much more is now known about the physical and chemical processes taking place during operation of the DSC, the exponential increase in research effort during this period has not been matched by large increases in efficiency. This raises questions regarding the nature of the barriers that are holding back progress and whether current research is adequately addressing the key issues that are currently limiting device performance. This Perspective attempts to identify some of the factors that determine DSC performance and, as part of a selective survey of recent research highlights, presents a personal view of new approaches and research strategies that could offer ways to overcome the current efficiency stalemate.

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The Grätzel Cell: Where Next?

Light scattering is a method that has been employed in dye-sensitized solar cells for optical absorption enhancement. In conventional dye-sensitized solar cells, large TiO2 particles with sizes comparable to the wavelength of visible light are used as scatterers by either being mixed into the nanocrystalline film to generate light scattering or forming a scattering layer on the top of the nanocrystalline film to reflect the incident light, with the aim to extend the traveling distance of incident light within the photoelectrode film. Recently, hierarchical nanostructures, for example nanocrystallite aggregates (among others), have been applied to dye-sensitized solar cells. When used to form a photoelectrode film, these hierarchical nanostructures have demonstrated a dual function: providing large specific surface area; and generating light scattering. Some other merits, such as the capability to enhance electron transport, have been also observed on the hierarchically structured photoelectrode films. Hierarchical nanostructures possessing an architecture that may provide sufficient internal surface area for dye adsorption and meanwhile may generate highly effective light scattering, make them able to create photoelectrode films with optical absorption significantly more efficient than the dispersed nanoparticles used in conventional dye-sensitized solar cells. This allows reduction of the thickness of the photoelectrode film and thus lowering of the charge recombination in dye-sensitized solar cells, making it possible to increase further the efficiency of existing dye-sensitized solar cells.

Applications of light scattering in dye-sensitized solar cells

Reference LPI-ARTICLE-2007-020View record in Web of Science Record created on 2007-05-07, modified on 2017-05-12

The Electronic Role of the TiO2 Light-Scattering Layer in Dye-Sensitized Solar Cells

In order to improve the photoenergy conversion efficiency of dye-sensitized solar cells (DSCs), it is important to optimize their porous electrodes. This paper examines the surface and cross-sectional views of the electrodes using scanning electron micrography. Two types of samples for cross-sectional viewing were prepared by mechanically breaking the substrate and by using an Ar-ion etching beam. The former displays the surface of the particles and the latter shows the cross-section of the particles. We found interesting surface and cross-sectional structures in the scattering layer containing the 400 nm diameter particles, which have an angular and horned shape. The influence of particle size and the thickness of the nanocrystalline- electrode in DSCs using four kinds of sensitizing dyes (D149, K19, N719 and Z907) and two kinds of electrolytes (acetonitrile-based and ionic-liquid electrolytes) are discussed in regards to conversion efficiency, which this paper aims to optimize.

https://downloads.hindawi.com/journals/ijp/2009/517609.pdf

Study of Dye-Sensitized Solar Cells by Scanning Electron Micrograph Observation and Thickness Optimization of Porous TiO2 Electrodes

An exhaust gas treatment apparatus includes a device (A) which is provided in an exhaust system and which selectively reduces NOx in an exhaust gas and a device (B) which is disposed upstream of the device (A) and which decomposes urea and supplies ammonia as a NOx reducing gas, the device (B) including a urea decomposition catalyst. The catalyst is [1] a zeolite catalyst which is composed of granular molded bodies including zeolite particles or which includes a catalyst layer composed of zeolite particles disposed on a support, or [2] a honeycomb catalyst or a membranous catalyst in which metal oxide particulates adhere to a conductive honeycomb substrate or netlike support, and the metal oxide particulates are composed of at least one oxide of a metal selected from the group consisting of Na, Mg, Ca, Ba, La, Ce, Ti, Zr, V, Cr, Mo, W, Mn, Zn, Al, Si, P, Sb, Cu, Fe, Ru, Co, and Re.

Exhaust gas treatment apparatus

Disclosed is a photoelectrical cell having excellent electron production ability, reduced re-binding of electrons, and high photoelectrical conversion efficiency. Also disclosed is a method for producing the photoelectrical cell. In the photoelectrical cell, a porous metal oxide semiconductor film comprises a titanium oxide particle which comprises a base particle and a titanium oxide microparticle layer which covers the surface of the base particle, wherein the base particle comprises titanium oxide.

Photoelectrical cell, and coating agent for forming porous semiconductor film for the photoelectrical cell

Disclosed is a metal-supported catalyst produced by (a) preparing a dispersion of crystalline silicoaluminophosphate particles; (b) mixing an aqueous active ingredient metal compound solution into the dispersion; (c) spray-drying the mixture; (d) washing the spray-dried product and (e) heat-treating (calcining) the washed product at 400 to 900°C. Also disclosed is an aluminum phosphate-modified metal-supported crystalline silicoaluminophosphate catalyst having a content of aluminum phosphate in the catalyst of 0.1 to 40% by weight in terms of Al2O3 + P2O5 based on the metal-supported crystalline silicoaluminophosphate particles.

Tsuguo Koyanagi

Papers

The Electronic Role of the TiO2 Light-Scattering Layer in Dye-Sensitized Solar Cells

Study of Dye-Sensitized Solar Cells by Scanning Electron Micrograph Observation and Thickness Optimization of Porous TiO2 Electrodes

Exhaust gas treatment apparatus

Photoelectrical cell, and coating agent for forming porous semiconductor film for the photoelectrical cell

Metal-supported crystalline silica aluminophosphate catalyst and process for producing the same