Graphene-wrapped light-emitting device
doi:10.1038/nindia.2017.64 Published online 8 June 2017
Researchers have synthesized a light-emitting material with potential for use in energy-saving next-generation display devices. The material was developed by wrapping a composite of zinc-sulfide-doped copper and aluminium and boron nitride with reduced graphene oxide1.
Inorganic materials exhibit electroluminescence, a state by which visible light is emitted in the presence of a strong electric field. However, these materials are unstable in air and show high turn-on voltages, limiting their large-scale applications in commercial display devices.
In search of better luminescent materials for display devices, scientists led by Bipin Kumar Gupta from the CSIR-National Physical Laboratory and University of Delhi prepared the electroluminescent material and tested its efficiency.
Unlike other exotic forms of carbon, such as carbon nanotubes, graphite, charcoal, and activated carbon, the use of reduced graphene oxide enhanced electrical conductivity, significantly improving the emission and brightness of the device.
During the fabrication of the device, structural features such as wrinkles, folds and twists formed on the surfaces. These features increased the surface contact area between graphene nanosheets, leading to increase in charge density and enhancement of the local electrical field.
“The new device is cheap and highly stable in air for several days, making it suitable for use in next-generation display devices,” says Gupta.
1. Gupta, B. K. et al. A novel electroluminescent device based on a reduced graphene oxide wrapped phosphor (ZnS: Cu, Al) and hexagonal-boron nitride for high-performance luminescence. Nanoscale. 9, 5002 (2017)