Compared to OLEDs, which are widely used in high-end consumer electronics, the perovskite-based LEDs, developed by researchers at the University of Cambridge, can be made at much lower costs, and can be tuned to emit light across the visible and near-infrared spectra with high colour purity.
The researchers have engineered the perovskite layer in the LEDs to show close to 100% internal luminescence efficiency, opening up future applications in display, lighting and communications, as well as next-generation solar cells.
These perovskite materials are of the same type as those found to make highly efficient solar cells that could one day replace commercial silicon solar cells. While perovskite-based LEDs have already been developed, they have not been nearly as efficient as conventional OLEDs at converting electricity into light.
Earlier hybrid perovskite LEDs, first developed by Professor Sir Richard Friend’s group at the University’s Cavendish Laboratory four years ago, were promising, but losses from the perovskite layer, caused by tiny defects in the crystal structure, limited their light-emission efficiency.
Now, Cambridge researchers from the same group and their collaborators have shown that by forming a composite layer of the perovskites together with a polymer, it is possible to achieve much higher light-emission efficiencies, close to the theoretical efficiency limit of thin-film OLEDs. Their results are reported in the journal Nature Photonics.
“This perovskite-polymer structure effectively eliminates non-emissive losses, the first time this has been achieved in a perovskite-based device,” said Dr Dawei Di from Cambridge’s Cavendish Laboratory, one of the corresponding authors of the paper. “By blending the two, we can basically prevent the electrons and positive charges from recombining via the defects in the perovskite structure.”
Reproduced courtesy of the University of Cambridge