Dye Sensitized Solar Cells (DSSC)

Yokohama, Japan, Feb 26, 2008
Source: JCN Newswire
http://www.japancorp.net/Article.Asp?Art_ID=17102

Peccell Technologies, Inc. has developed a technology to produce large-area high-voltage film-type dye-sensitized solar cell (DSC) modules with a high-speed, low-cost printing process. Peccell, based in Yokohama City and led by Prof. Tsutomu Miyasaka, Toin University of Yokohama, has been developing next-generation thin flexible DSCs jointly with Fujimori Kogyo Co., Ltd. and Showa Denko K.K.

The newly developed technology enables the formation of a 15-micron-thick titania semiconductor layer, which serves as a power generation layer, on a plastic film at ordinary temperatures and by a rapid printing process. A special paste, consisting of nano-scale fine particles of crystalline titania provided by SDK, is used in the process. Under the conventional process, titania-based semiconductor layers are formed in a vacuum and through baking at high temperatures, requiring the use of large-scale facilities.

Furthermore, a special transparent conductive film having a metal-micro-grid structure is coated on the plastic substrate. Compared with the conventional indium-tin-oxide (ITO) film, the new transparent conductive film has only 1/20 surface resistance. Peccell and Fujimori have jointly developed a technology to coat the transparent conductive film by a low-cost printing process, getting rid of the need of processing in a vacuum. The new substrate will ensure high durability when used in DSCs.

The newly developed transparent conductive film has high light transmittance of more than 75%. At the same time, electrical resistance of the sheet is very low at 0.3 Omega, about 1/100 to 1/500 that of a polyethylene terephthalate film coated with ITO. The new plastic substrate is chemically stable when used in DSCs. Compared with the conventional ITO-PET film (electrical resistance: 20 Omega or less), the production cost of the new substrate is halved, as it is produced with a high-speed roll-to-roll process. There is a growing need for transparent conductive films for use in LCDs and electronic devices operated by means of touching a panel.

There is a growing need for transparent conductive films for use in LCDs and electronic devices operated by means of touching a panel. Transparent electrodes for solar cells, however, are required to have particularly low surface resistance of less than 10 Omega, because high resistance results in lower output. This time, Peccell has realized a substrate with very low surface resistance, enabling the production of a high-voltage large-area component for DSCs. For potential users, the new conductive film gives a semi-transparent body to the DSC module, creating smart applications to windows and panels, and will ensure high durability even at high temperature.

Peccell has developed an integrated solar cell module using the special titania paste and the plastic substrate coated with the special transparent conductive film. The company has also used its precision sealing technology to substantially increase the numerical aperture (the percentage of the power-generating area in the total area) from around 80% to 90% or more, enhancing the performance of the solar cell.

As the new module is of a thin-film type, the use of electrolyte and other materials has been reduced to one-fifth, resulting in a substantial decline in production cost. The newly developed solar cell module of Peccell measures 0.8 m in width, 2.1 m in length, representing the largest size in the world. Furthermore, its thickness is only 0.5 mm, and its weight is 800 g per square meter, the lightest solar cell in the world. The module can generate a high voltage of 100 V or more even when it is installed indoors. Peccell's new solar cell module will be exhibited at the first International Photovoltaic Power Generation Expo (PV EXPO 2008) to be held at the Tokyo Big Sight from February 27 through 29.

Because of their lightweight, safety and crack resistance, plastic-based solar cells are in increasing demand as a power source in mobile electronic devices, PCs and game devices. While the consumer electronics market is growing rapidly, the conventional solar cells, which use such solid state components as silicon and CIS, involve high production costs, and therefore cannot be supplied at low prices for these applications.

Peccell is planning to build a trial production line for the newly developed solar cell and begin shipment of samples by the end of 2009.