New polymer for use in solar cells with higher efficiency levels

28-Nov-08

A research team at America's UCLA Henry Samueli School of Engineering and Applied Science have designed and synthesized a new polymer for use in solar cells which leads to significantly greater sunlight absorption and conversion capabilities than previous polymers, reports the Nov. 26 edition of the Journal of the American Chemical Society. The report described by Yang Yang, a professor of materials science and engineering, and other team members described substituting a silicon atom for carbon atom in the backbone of the polymer which improves the material's photovoltaic properties. This silole-containing polymer can also be crystalline, giving it great potential as an ingredient for high-efficiency solar cells. As opposed to the less efficient polymer solar cells, the new polymer created by Yang's team reached 5.1% efficiency in the published study but has in a few months improved to 5.6% in the lab. However, the team aims to reach the performance level to more than 10% efficiency for the polymer solar cells. The new photovoltaic material used on their solar cells is one of the most efficient based on a single-layer, low-band-gap polymer. At a lower band gap, the polymer solar cell can better utilize the solar spectrum, thereby absorbing more sunlight as opposed to higher band gap. As opposed to earlier complicated methods for producing polymer solar cells, the effort of this research team has simplified the synthesis suitable for mass production. Also, the polymer solar cells itself are much cheaper to produce than traditional silicon-based solar cells and are also environmentally friendly.