Professor Hyun-jung Lee and her team developed a new technology which can greatly increase the efficiency of the organic solar battery. The key point of this research is the technology of producing titanium oxide (TiO2) photonic crystal film, a futuristic material, quickly, and in a large scale. The titanium oxide film produced with this technology proved its usefulness as the film is successfully applied to the future solar battery, a dye sensitized solar cell (DSSC).

This research is supported by the Ministry of Education, Science and Technology and the National Research Foundation of Korea as a response to the Climate Change Project (Project leader: Hyun-jung Lee, September 2009 ~ September 2011). The result of this research was published as a frontispiece in the online edition of world-renowned ‘Advanced Functional Materials’ on August 23, 2011.

Titanium oxide is widely used as a core material for photo catalyst, UV blocker and white paint, because of its unique physical and chemical properties. In addition, titanium oxide is appropriate as a material for photonic crystal, due to its high refractive index. Photonic crystal is a grid-arrayed material with one to three dimensions, made of a transparent and solid substance. This material can be used to store and amplify the solar energy.

Titanium oxide is also a core material of DSSC, which is in the spotlight as the future energy technology that can compensate the defects of silicon solar batteries. As it is expected to bring a great increase in the efficiency of solar batteries, many countries including the US have conducted research on this photonic crystal technology over the last ten years. However, because of the technical difficulties, the theoretical prediction didn’t actually correspond with the actual results.

In this study, Professor Lee’s team produced a photonic film complex, using new technology called the slide coating method. With this technology, it is possible to precisely array the combined liquid complex of titanium oxide nano-particles and high-molecule micro particles on a substrate. Afterwards, a heating process successfully transformed it into a titanium oxide inverse opal photonic film. By using the produced titanium oxide inverse opal film as a photoelectrode, the generating efficiency was remarkably increased when compared to the existing solar batteries. More than a 50% increase in the efficiency was achieved compared to studies conducted two years ago by the same team.

Since the titanium oxide photonic film produced by Professor Lee’s team has high stability and process capabilities, it can be used in many different types of solar batteries, and is expected to be applied to diverse fields such as laser, photo catalysis, etc.