Alternative Energy
Despite
more than 50 years of development, the cost of the current generation
of inorganic silicon solar cells is very high and further breakthroughs
in cost and efficiency using traditional materials are looking
increasingly less likely. Compared with silicon, next-generation
organic solar cells hold the promise of low-cost, liquid-based,
large-area fabrication technology at room temperature. At VCU we are
investigating photovoltaics made using polymer-based semiconductors. In
addition to lower costs, photovoltaics provide a number of potential
advantages for solar cells. By modifying the chemical structure, the
band gap and ionization potential can be tuned to absorb the desired
parts of the solar spectrum. They also are generally flexible which
offers the possibility of integration into building materials and
appliances. Several research groups have reported on devices with
conversion efficiencies more than 5 percent.
While 5 percent efficiency is promising, polymer-based solar cells must achieve efficiencies of 10 to 20 percent in order compete with more established technologies. To reach this goal, a number of challenges must be overcome. In particular, it is important to increase the low photocurrents in these devices that result from poor light harvesting, poor charge generation and poor charge transport. Our research is focused on using a water-soluble photoconducting polymer to develop novel photovoltaic device structures and overcome these challenges.