Research has been undertaken in Korea revealing that the expensive metal found in a number of solar cells can be replaced with cheap resins.
A very important type of solar cell known as dye-sensitised solar cells (DSSCs) is possibly the most researched form of solar cell technology. It has several important benefits such as being very efficient and flexible but is somewhat hindered by incorporating some expensive components.
At the present time, 30% of the cost of DSSCs’ costs are due to the various metal-based dyes that are required to sensitise the Titania photocatalyst that allows it to harvest the spectrum’s more beneficial visible part.
Wonyong Choi – Professor at Pohang University
Wonyong Choi is a professor at the School of Environmental Science and Engineering in Pohang University of Science and Technology in Korea. His group has been able to replace the above metal-based dyes with some inexpensive phenolic resins.
He had previously been able to demonstrate that phenol, when it was connected to Titania, actually revealed the required ligand-to-metal charge transfer (LMCT) property when seen under visible light. However, regrettably a number of problems occurred that stopped it being used.
He explained: ‘Phenol alone forms a very weak LMCT complex on TiO2 and its surface complex is not stable. By polymerising phenols into a resin form, the LMCT complex is stronger and absorbs more visible light.’
The group undertaking the research managed to connect the resin onto TiO2 just by dispersing the TiO2 powder and resin within acetone solvent. The material that resulted revealed visible light hydrogen production together with the degradation of dye – two other potential uses.
Erwin Reisner, who is a photocatalyst expert working at the University of Cambridge in the United Kingdom was complimentary of the novel and nonsense – free nature of this catalyst stating: ‘It’s straightforward, works for relevant conditions and seems to be quite inexpensive.’ He encouraged the group of people carrying out the research to completely test the material using a solar cell device so as to establish any impact.
The researchers acknowledge that this is a matter to be looked at in the future but, for the time being, want to concentrate on improving the dye.
Wonyong Choi stated: ‘The main problem is relatively low efficiency of visible light absorption and stability but we are working to modify the structure of phenolic resin to enhance the efficiency of visible light absorption and stability.’
