Self-assembly brightens LED future
14 Feb 2017 by Evoluted New Media
Researchers at Princeton, have created a technique enabling the self-assembly of perovskite crystals to produce more efficient, stable and durable LEDs.
Researchers at Princeton, have created a technique enabling the self-assembly of perovskite crystals to produce more efficient, stable and durable LEDs.
Potential applications of his research could see perovskite crystals used in televisions, computer screens, lighting and also lasers. Perovskites are more efficient and are a possible low-cost alternative to relying on ‘conventional’ LEDs.
Professor Barry Rand, from Princeton University, and lead researcher, said: “Our new technique allows these nanoparticles to self-assemble to create ultra-fine grained films, an advance in fabrication that makes perovskite LEDs look more like a viable alternative to existing technologies.”
Conventional LEDs have many advantages over incandescent bulbs such as durability, smaller size and energy efficiency. Researchers have been exploring the use of perovskites as a lower-cost alternative to gallium nitride (GaN) and other materials used in LED manufacturing. This could also help lessen the environmental impacts of current LEDs.
Professor Rand said: “The performance of perovskites in solar cells has really taken off in recent years, and they have properties that give them a lot of promise for LEDs, but the inability to create uniform and bright nanoparticle perovskite films has limited their potential.”
Rand and his team dissolved perovskite precursors in a solution containing a metal and an organic ammonium halide. They also added an additional long-chain ammonium halide to this solution, which limited the formation of the crystals’ size in the film. The resulting crystals were between five and 10nm, with the resulting halide film more thin and smooth. This resulted in better quantum efficiency – more photons emitted per number of electrons entering the device – as well as being more stable than those produced by other methods.
Originally discovered in the mid-1800s in Russia, perovskite was named after the Russian mineralogist Leve Perovski. Perovskites include compounds that share the same crystalline structure of the original mineral – a distinct combination of cuboid and diamond shapes.
The research was published in Nature Photonics.
