Perovskites are materials that share a crystal structure similar to the mineral called perovskite, which consists of calcium titanium oxide (CaTiO3).
Depending on which atoms/molecules are used in the structure, perovskites can possess an impressive array of interesting properties including superconductivity, ferroelectricity, charge ordering, spin dependent transport and much more. Perovskites therefore hold exciting opportunities for physicists, chemists and material scientists.
Sensors are devices that detect events that occur in the physical environment (like light, heat, motion, moisture, pressure, and more), and respond with an output, usually an electrical, mechanical or optical signal. The household mercury thermometer is a simple example of a sensor - it detects temperature and reacts with a measurable expansion of liquid. Sensors are everywhere - they can be found in everyday applications like touch-sensitive elevator buttons and lamp dimmer surfaces that respond to touch, but there are also many kinds of sensors that go unnoticed by most - like sensors that are used in medicine, robotics, aerospace and more.
Traditional kinds of sensors include temperature, pressure (thermistors, thermocouples, and more), moisture, flow (electromagnetic, positional displacement and more), movement and proximity (capacitive, photoelectric, ultrasonic and more), though innumerable other versions exist. sensors are divided into two groups: active and passive sensors. Active sensors (such as photoconductive cells or light detection sensors) require a power supply while passive ones (radiometers, film photography) do not.
Perovskite materials’ host of exciting properties, such as being rather tolerant to defects (unlike metal chalcogenides) and not requiring surface passivation to retain high quantum yields, make them especially suited for sensing applications. The sensitivity, selectivity, and stability of many perovskite nanomaterials has directed many researchers to devote the most attention to chemical sensors, but perovskites are suitable for other types as well. Perovskites are being studied by numerous research groups for use in various types of sensors.
The latest Perovskite sensor news:
Scientists at EPFL and their collaborators have developed a simple and low-cost perovskite-based device that detects neutrons. The perovskite materials used in the study are based on lead and bromine. Both contain single crystals of a compound called methylammonium lead tri-bromide.
The team first placed these crystals in the path of a neutron source. The neutrons, hitting the crystals, penetrate the nucleus of the atoms within the crystal, exciting them into a higher energy state. When they relax and decay, gamma rays are created. These gamma photons charge the perovskite, delivering a tiny current that can be estimated.
The U.S. Defense Advanced Research Projects Agency (DARPA) is currently seeking research proposals for the development of x-ray technology capable of what the agency calls "extreme photo imaging."
As part of its Extreme Photon Imaging Capability - Hard X-Ray (EPIC-HXR) project, DARPA said it is looking to develop uncooled hard x-ray imagers based on advanced nanocrystalline materials with high spatial and energy resolution, including quantum dot and perovskite materials.
Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have reported a breakthrough in energy-efficient phototransistors - devices that could someday help computers process visual information similarly to the human brain and be used as sensors in applications like self-driving vehicles.
The structures rely on metal-halide perovskites. Jeffrey Blackburn, a senior scientist at NREL and co-author of a new paper outlining the research, said: “In general, these perovskite semiconductors are a really unique functional system with potential benefits for a number of different technologies”. “NREL became interested in this material system for photovoltaics, but they have many properties that could be applied to whole different areas of science.”
A University of North Texas researcher and his team have reported a breakthrough in using additive manufacturing to further research into flexible solar panels.
Anupama Kaul, Professor of Engineering from the Departments of Materials Science and Engineering and Electrical Engineering, has successfully used additive manufacturing to print inks of 2D perovskites.
Various dangerous chemicals are currently used for agriculture and industry, including fumigants like methyl iodide, which is used to control insects and fungi. The wrong amounts or incorrect use of these fumigants can be harmful to people and degrade the ozone layer. As it’s invisible and doesn’t smell, it’s hard to tell whether there are dangerous amounts of methyl iodide present, and until now the best way to test for it was in a laboratory using expensive, complicated equipment, which isn’t practical in many real-world settings. Some cheaper, lightweight detection methods have been tried, but they didn’t have enough sensitivity and took too long to deliver results.
Now, a research team led by the ARC Centre of Excellence in Exciton Science, along with Australia’s national science agency CSIRO and the Department of Defense, has found a perovskite-based way to detect methyl iodide, with the accuracy, flexibility and speed necessary for practical use. This new sensing mechanism is also versatile enough for use in detecting a wide range of fumigants and chemical warfare agents.