The secret: diatoms.
These tiny, single-celled marine life forms have existed for at least 100 million years and are the basis for much of the life in the oceans, but they also have rigid shells that can be used to create order in a natural way at the extraordinarily small level of nanotechnology.
By using biology instead of conventional semiconductor manufacturing approaches, researchers at OSU and Portland State University have created a new way to make "dye-sensitized" solar cells, in which photons bounce around like they were in a pinball machine, striking these dyes and producing electricity. This technology may be slightly more expensive than some existing approaches to make dye-sensitized solar cells, but can potentially triple the electrical output.
"Most existing solar cell technology is based on silicon and is nearing the limits of what we may be able to accomplish with that," said Greg Rorrer, an OSU professor of chemical engineering. "There's an enormous opportunity to develop different types of solar energy technology, and it's likely that several forms will ultimately all find uses, depending on the situation."
Dye-sensitized technology, for instance, uses environmentally benign materials and works well in lower light conditions. And the new findings offer advances in manufacturing simplicity and efficiency.
"Dye-sensitized solar cells already exist," Rorrer said. "What's different in our approach are the steps we take to make these devices, and the potential improvements they offer."
The new system is based on living diatoms, which are extremely small, single-celled algae, which already have shells with the nanostructure that is needed. They are allowed to settle on a transparent conductive glass surface, and then the living organic material is removed, leaving behind the tiny skeletons of the diatoms to form a template.
A biological agent is then used to precipitate soluble titanium into very tiny "nanoparticles" of titanium dioxide, creating a thin film that acts as the semiconductor for the dye-sensitized solar cell device. Steps that had been difficult to accomplish with conventional methods have been made easy through the use of these natural biological systems, using simple and inexpensive materials.
"Conventional thin-film, photo-synthesizing dyes also take photons from sunlight and transfer it to titanium dioxide, creating electricity," Rorrer said. "But in this system the photons bounce around more inside the pores of the diatom shell, making it more efficient."
The physics of this process, Rorrer said, are not fully understood – but it clearly works. More so than materials in a simple flat layer, the tiny holes in diatom shells appear to increase the interaction between photons and the dye to promote the conversion of light to electricity, and improve energy production in the process.
The insertion of nanoscale tinanium oxide layers into the diatom shell has been reported in ACS Nano, a publication of the American Chemical Society, and the Journal of Materials Research, a publication of the Materials Research Society. The integration of this material into a dye-sensitized solar cell device was also recently described at the fourth annual Greener Nanoscience Conference.
The work is supported by the National Science Foundation and the Safer Nanomaterials and Nanomanufacturing Initiative, a part of the Oregon Nanoscience and Microtechnologies Institute.
Diatoms are ancient, microscopic organisms that are found in the fossil record as far back as the time of the dinosaurs. They are a key part of the marine food chain and help cycle carbon dioxide from the atmosphere.
But in recent years their tiny, silica shells have attracted increasing attention as a way to create structure at the nano level. Nature is the engineer, not high tech tools. This is providing a more efficient, less costly way to produce some of the most advanced materials in the world.
Editor's Note: The professional publication this story is based on can be found at this URL: http://pubs.acs.org/doi/full/10.1021/nn800470x
Greg Rorrer | EurekAlert!
Further reports about: > Ancient African Exodus > Ancient diatoms > Dye-sensitized technology > Nanoscience > OSU > biological system > extraordinarily small level of nanotechnology > glass surface > natural biological systems > photo-synthesizing dyes > pinball machine > semiconductor manufacturing > silicon-based solar cells > single-celled algae > single-celled marine life forms > solar cells > solar energy > solar energy technology > titanium dioxide
Supersonic waves may help electronics beat the heat
18.05.2018 | DOE/Oak Ridge National Laboratory
Researchers control the properties of graphene transistors using pressure
17.05.2018 | Columbia University
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology