Ohio State University chemists and their colleagues have created a new material that overcomes two of the major obstacles to solar power: it has an absorption spectrum that closely matches that of the solar spectrum, and it generates long-lived excited electrons that should allow solar cells to generate electricity more efficiently.
To design the hybrid material, which combines electrically conducive plastic with metals, including molybdenum and tungsten, the chemists first explored different molecular configurations using the high performance computing systems at the Ohio Supercomputer Center. Then, with colleagues at National Taiwan University, they synthesized molecules of the new material in a liquid solution, measured the frequencies of light the molecules absorbed, and also measured the length of time that excited electrons remained free in the molecules.
The chemists found that the new hybrid material emits photons in two different energy states — one called a singlet state, and the other a triplet state. While both energy states are useful for solar cell applications, the triplet state lasts much longer than the singlet state — which improves the ability to harness their power, explained Malcolm Chisholm, Ph.D., distinguished university professor and chair of the department of chemistry at Ohio State.
At this point, the material is years from commercial development, but Dr. Chisholm added that this experiment provides a proof of concept — that hybrid solar cell materials can offer unusual and beneficial properties.
Project lead: Malcolm Chisholm, Ph.D., The Ohio State University
Research title: The remarkable influence of MM delta orbitals with oligothiophenes
Funding sources: National Science Foundation & Ohio State’s Institute for Materials Research, together with Wright Center funding for photovoltaic initiative for commercialization