Donor-acceptor polymers and complexes for photocells and photoinduced H2-evolution

点击翻译按钮获取中文摘要

This proposal entitled "Donor-acceptor polymers and complexes for photocells and photoinduced H2-evolution" deals with two specific themes related to clean energy. 1- Low band gap polymers for applications in the design of polymer photovoltaic cells. 2- Photoinduced H2 evolution (PHE) using new homogeneous difunctional dye-Pt2 catalysts. The conversion of sun light into electricity is now a subject of high public interest for obvious economic and environmental issues and funding in this area is increasingly being dedicated by different governments (federal and provincial) and industry. The current tendency is focussed on plastic solar cells as they appear to be cheaper to produce in comparison with the rigid solid state solar panels designed with semi-conducting silicon materials. In this proposal, the design of new polymers will be made focussing onto two key parameters. First, the materials should absorb more photons at a given wavelength, a property called absorptivity. Second, the materials should absorb more photons in the red region of the solar spectrum. The latter is achieved by building the polymers upon a repetitive sequence of (donor-acceptor)n in a conjugated manner (i.e. electronically communicating across the chain). This creates donor-acceptor interactions called charge transfer and a new absorption band appears in the red region. The conversion of sun light and water directly into hydrogen is appealing because it is obviously clean but also can be considered economically viable in a non-so remote future if one considers the current best efficiencies for plastic solar cells (about 7-8 %) and hydrolysis of water (H2O = H2 + 1/2 O2; about 50%). The design of the proposed new catalysts which is soluble in common organic solvents consists of 2 to 4 dyes attached to a diplatinum species. The role of the dye is to absorb the light which will help trigger an electron transfer to the diplatinum species which is prone to absorb protons from added water or acids. So, the overall reaction is H+ + 1e- + light = 1/2 H2.