The ultimate step in applying solar power is to convert uttermost energy from sun into electricity. This will make solar power extremely cost-advantageous compared to other traditional power sources. Seizing energy wasted as heat from the sun can increase solar transition efficiency greatly. Research funded by the U.S. Department of Energy is on-going to make this happen.
Not all solar energy utilized:
In reality only approximately 31% of solar energy is changed over into electricity. The rest of the energy is not able to be harnessed as it becomes heat – as ‘hot electrons’ – which is lost very rapidly because electrons cool down very quick. Capturing just about all solar energy and converting to electricity is the goal of the ‘ultimate solar cell’.
Utilizing the hot electrons:
Since half the solar energy is lost as heat, the first step will be to slow down the cooling rate of these electrons. The second step will be to seize the hot electrons and use them before the heat energy gets dissipated and lost. And harness the heat energy taking the electrons out via a conducting wire with minimum energy loss.
Semiconductor nanocrystals – quantum dots:
Quantum dots play a pivotal function in the transfer of hot electrons. The research demonstrated that the hot electrons can be transferred to a titanium dioxide electron conductor with the help of photo-excited lead selenide nanocrystals (quantum dots). The aim is to minimize energy loss by having the most efficient conductor wire. This will provide the fast removal of electrons from the solar cell before they cool down.
Solar power – the best energy source:
With growing awareness of dwindling sources of fossil fuels, green, environmentally friendly, bio-renewable energy sources are beacon lights of energy sources in future. Solar energy will be the most efficient and basic source of such energy. This research is an important step in the existence of the ultimate solar cell.
The team:
Chemist, Xiaoyang Zhu, University of Texas, Austin, led the team consisting of William Tisdale, Brooke Timp, David Norris and Eray Aydil – all from the University of Minneso and also Kenrick Williams, from University of Texas.