Organic solar cell Dye sensitization Organic thin film Photoelectric conversion
Studies on organic solar cells have their roots in photosynthetic system models of plants and bacteria and have a history of about half a century. Compared to existing silicon solar cells, they attract attention in terms of lower costs and greater processing flexibility in shape. In addition, due to a series of technical breakthroughs which enabled drastic improvements in conversion efficiency in recent years, development is being accelerated, while attracting much greater interest.
Our laboratory is involved in studies aiming for achievement of higher-efficiency and more durable organic solar cells. Further, concerning solar cells including dye-sensitized solar cells, we have accumulated much know-how in terms of theories, materials, practical applications for devices, and evaluation.
Dye-sensitized solar cells in which organic dyes and titanium dioxide are hybridized have a unique characteristic where color tones can be varied in addition to the characteristic that the cost is low and manufacturing is easy.
Aiming for higher efficiency and clarification of mechanisms of dye-sensitized solar cells, we are involved in studies on the synthesis of new dye-sensitized solar cells and on solid-state properties by using the electron spin resonance technique and electrochemical means. By applying surface treatment on a TiO2 nanoparticle electrode before applying dye adsorption (electrochemical intercalation of Li atoms), we found that the photo voltage of the solar cell significantly increases, which contributes to enhanced energy conversion efficiency, as a result.