Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A good first step toward nontoxic solar cells

29.07.2019

Engineers discover lead-free perovskite semiconductor for solar cells using data analytics, supercomputers

Solar panel installations are on the rise in the U.S., with more than 2 million new installations in early 2019, the most ever recorded in a first quarter, according to a recent report by Solar Energy Industries Association and Wood Mackenzie Power & Renewables.


This is an atomic model of KBaTeBiO6 (left), the most promising of 30,000 oxides in a potential solar panel. At right is a scanning transmission electron micrograph showing the atomic structure of KBaTeBiO6, along with snapshot of the synthesized powder.

Credit: Rohan Mishra

To meet the ever-increasing demands, low-cost and more efficient alternatives to silicon-based solar cells -- currently the most widely used technology -- are desirable.

In the past decade, lead-halide perovskites have surged as the most promising class of alternative materials; however, they are unstable. They contain lead, which is toxic and poses potential health and environmental hazards such as groundwater contamination.

A team of engineers at Washington University in St. Louis has found what they believe is a more stable, less toxic semiconductor for solar applications using a novel double perovskite oxide discovered through data analytics and quantum-mechanical calculations.

Their work was published online June 11 in Chemistry of Materials.

Rohan Mishra, assistant professor of mechanical engineering & materials science in the McKelvey School of Engineering, led an interdisciplinary, international team that discovered the new semiconductor, made up of potassium, barium, tellurium, bismuth and oxygen (KBaTeBiO6). The lead-free double perovskite oxide was one of an initial 30,000 potential bismuth-based oxides. Of those 30,000, only about 25 were known compounds.

Using materials informatics and quantum mechanical calculations on one of the fastest supercomputers in the world, Arashdeep Singh Thind, a doctoral student in Mishra's lab based at Oak Ridge National Laboratory, found KBaTeBiO6 to be the most promising out of the 30,000 potential oxides.

"We found that this looked to be the most stable compound and that it could be synthesized in the lab," Mishra said. "More importantly, whereas most oxides tend to have a large band, we predicted the new compound to have a lower band gap, which is close to the halide perovskites, and to have reasonably good properties."

The band gap is the energy barrier that electrons must overcome to form free carriers that, in the context of a solar cell, can be extracted to power an electrical device or stored in a battery for later use. The energy to overcome this barrier is provided by sunlight. The most promising compounds for solar cell applications have a band gap of about 1.5 eV, or electronvolt, Mishra said.

Mishra discussed the possibility of synthesizing KBaTeBiO6 with Pratim Biswas, assistant vice chancellor, the Lucy & Stanley Lopata Professor and chair of the Department of Energy, Environmental & Chemical Engineering. Shalinee Kavadiya, then a McKelvey Engineering doctoral student and now a postdoctoral research associate at Arizona State University, got to work on perfecting the recipe.

"Shalinee spent about six months synthesizing the material," Mishra said. "Once she was able to synthesize it, as we had predicted, it was stable and had a band gap of 1.88 eV, which we also predicted."

Mishra said these are first-generation solar cells that need more fine tuning of the band gap, but it is a good first step toward nontoxic solar cells.

"This shows that we can go away from these lead-halide perovskites," Mishra said. "This opens up a really big space for designing semiconductors not just for solar cell applications but also for other semiconductor applications, such as LCD displays."

Next, the team will study the role of any defects in this new semiconductor and look to more advanced synthesis techniques, including using aerosol techniques.

Brandie Jefferson | EurekAlert!
Further information:
https://source.wustl.edu/2019/07/a-good-first-step-toward-nontoxic-solar-cells/
http://dx.doi.org/10.1021/acs.chemmater.9b01025

More articles from Materials Sciences:

nachricht KIST researchers develop high-capacity EV battery materials that double driving range
24.02.2020 | National Research Council of Science & Technology

nachricht OrganoPor: Bio-Based Boards for A Thermal Insulation Composite System
21.02.2020 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: High-pressure scientists in Bayreuth discover promising material for information technology

Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.

The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...

Im Focus: From China to the South Pole: Joining forces to solve the neutrino mass puzzle

Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics

Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...

Im Focus: Therapies without drugs

Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.

A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Scientists 'film' a quantum measurement

26.02.2020 | Physics and Astronomy

Melting properties determine the biological functions of the cuticular hydrocarbon layer of ants

26.02.2020 | Interdisciplinary Research

Lights, camera, action... the super-fast world of droplet dynamics

26.02.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>