Abstract
The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in high-quality displays, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Here we demonstrate a bright spectrally tunable electroluminescence from blue (∼450 nm) to red (∼750 nm) at the graphene oxide/reduced-graphene oxide interface. We explain the electroluminescence results from the recombination of Poole–Frenkel emission ionized electrons at the localized energy levels arising from semi-reduced graphene oxide, and holes from the top of the π band. Tuning of the emission wavelength is achieved by gate modulation of the participating localized energy levels. Our demonstration of current-driven tunable LEDs not only represents a method for emission wavelength tuning but also may find applications in high-quality displays.
Highlights
The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in highquality displays, yet this capability has not been demonstrated in existing LEDs
We demonstrate a desirable combination of a bandgap structure and a bipolar carrier injection in a special type of semi-reduced graphene oxide (GO)
In summary, we have reported the design and implementation of a LED device based on a special type of semi-reduced GO that forms in the rGO/GO interface
Summary
The continuous tuning of the emission spectrum of a single light-emitting diode (LED) by an external electrical bias is of great technological significance as a crucial property in highquality displays, yet this capability has not been demonstrated in existing LEDs. Graphene, a tunable optical platform, is a promising medium to achieve this goal. Graphene is an amendable platform whose electronic and optical properties can be tailored by chemical and electrical means This property is interesting as it potentially provides a way to in situ control the colour of LEDs. various high-performance graphene-based photonic devices have been reported[13,14,15,16,17], the development of graphene-based LEDs has been unsuccessful owing to its vanishing bandgap. The device shows a high brightness of up to 6,000 cd m À 2, with efficiency around 1%
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