The lighting industry has been changed forever by LEDs, and now they could become even cheaper and more efficient with the incorporation of perovskites. New LED is made with crystalline substances known as perovskites. (Photo via Sameer A. Khan/Fotobuddy)


The advent of light emitting diodes (LEDs) have revolutionized lighting because of their efficiency, durability, and longevity, and now Princeton engineering researchers have further improved the revolutionary light source through the use of perovskites. These are crystalline substances that belong to a class of compounds that have the same structure as perovskite (CaTiO3 ), a calcium titanium oxide mineral.


According to perovskite-info.com (an aptly named website): “... perovskites can have an impressive array of interesting properties including “colossal magnetoresistance” - their electrical resistance changes when they are put in a magnetic field (which can be useful for microelectronics)”, and they have several practical applications in, “...sensors and catalyst electrodes, certain types of fuel cells, solar cells, lasers, memory devices and spintronics applications.” Now perovskites are entering LED technology and they present, “... a potential lower-cost alternative to gallium nitride (GaN) and other materials used in LED manufacturing,” according to Barry Rand, an assistant professor of electrical engineering and the Andlinger Center for Energy at Princeton. This potential reduction in price makes LEDs more and more attractive given that they are more durable, efficient and long-lasting, but also more expensive than incandescent and fluorescent bulbs.


In the abstract of Rand’s initial report, it was noted that perovskites have promising potential for LEDs because of their, “high colour purity, low non-radiative recombination rates and tunable bandgap.” Rand and the other researchers found that the perovskite LEDs were found to be highly efficient, and enabled by the formation of “self-assembled, nanometre-sized crystallites.” It was found that when a long-chain organic ammonium halide was added to the perovskite solution, it resulted in smaller crystallites on the halide perovskite film, and according to Phys.org, this improves the “external quantum efficiency, meaning the LEDs emitted more photons per number of electrons entering the device”, and the films were also more stable than those produced through other means.


Professor of materials science and engineering at the University of Minnesota, Russell Holmes, believes that the Princeton research brings perovskite-based LEDs closer to commercialization. These developments would make LEDs an even tougher competitor in the lighting industry, and the wide application perovskites have demonstrated in increasingly important technologies like solar cells is also a nice caveat.


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