Quantum-dot-based LED has lifetime of  more than 100,000 hours at 100 cdm^-2

Solution-processed LEDs using conjugated polymers or quantum dots as emitters have created interest over the past two decades for their potential for low-cost fabrication on flexible plastic substrates. However, the overall performance of such LEDs  -  including their efficiency, efficiency roll-off at high current densities, turn-on voltage and lifetime under operational conditions - is not as good as the best vacuum-deposited organic LEDs.

Now scientists from Zhejiang University, Chinese Academy of Sciences, and Nanjing Tech University have reported a solution-processed, multilayer quantum-dot-based LED with excellent performance and reproducibility.

Their quantum dot LED, which was the subject of a paper in Nature today, exhibits colour-saturated deep-red emission, sub-bandgap turn-on at 1.7V, high external quantum efficiencies of up to 20.5 percent, low efficiency roll-off (up to 15.1 per cent of the external quantum efficiency at 100 mA cm^-2), and a long operational lifetime of more than 100,000 hours at 100 cd m^-2.

According to to the researchers, this makes making this device the best-performing solution-processed red LED so far, comparable to state-of-the-art vacuum-deposited organic LEDs.

The optoelectronic performance is achieved by inserting an insulating layer between the quantum dot layer and the oxide electron-transport layer to optimise charge balance in the device and preserve the superior emissive properties of the quantum dots.

The researchers anticipate that the results will be a starting point for further research, leading to high-performance, all-solution-processed quantum-dot-based LEDs ideal for next-generation display and solid-state lighting technologies.

'Solution-processed, high-performance light-emitting diodes based on quantum dots' by Xingliang Dai et al, appears in Nature (2014) doi:10.1038/nature13829

AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

We shall also look at microLEDs, a display with many wonderful attributes, identifying processes for handling the mass transfer of tiny emitters that hold the key to commercialisation of this technology.

We shall also discuss electrification of transportation, underpinned by wide bandgap power electronics and supported by blue lasers that are ideal for processing copper.

Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

Having attracted 1500 delegates over the last 2 online summits, the 3rd event promises to be even bigger and better – with 3 interactive sessions over 1 day and will once again prove to be a key event across the semiconductor and photonic integrated circuits calendar.

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