Electroplating boosts solar cells

One way to improve solar cells is to find inexpensive materials to replace the silicon currently used to gather light energy and convert it to electricity.

One line of research taps dye molecules to gather photons. Researchers from the Kyushu Institute of Technology in Japan and the University of Texas at Arlington have shown that including titania in the mix makes the dye more efficient.

The composite could be used in solar cells that are relatively inexpensive to manufacture. The material could also be used in water purification and chemical and biological sensing applications, according to the researchers.

To make the material the researchers deposited 7.8-micron-thick oxide films containing titania nanoparticles onto a tin oxide-fluorine substrate. A micron is one thousandth of a millimeter. The material contains nano pores, or tiny holes, that are several orders of magnitude smaller than its thickness.

The titania particles made the material more efficient at separating negatively-charged electrons from positively-charged holes. Solar cells use photon energy to excite and move electrons into a circuit to generate electricity.

It is likely take one or two decades to make the material efficient enough for practical solar cells, according to the researchers. Their prototype has an efficiency of four percent. An existing sol-gel method of producing titania films currently yields more efficient solar cells, but is less amenable to mass production, according to the researchers.

The work appeared in the November 4, 2003 issue of Advanced Materials.