Feature: Displays
Quantum dots in EL-QD displays By IDTechX analysts
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uantum dots are semiconductor nanocrystals, which due to their size and structure offer optical and electronic properties much better than
any other, larger-particle technology. They are only between 2nm and 10nm large, but enable highly realistic and high-definition displays for TVs, monitors and smart tablets. Quantum dots were discovered in
1980 and, in 2023, the Nobel Prize for Chemistry was awarded to Moungi G. Bawendi, Louis E. Brus and Aleksey Yekimov for their discovery and synthesis. Quantum dots comprise a core,
shell and an outer layer of ligands that stabilise the particles and give them their qualities. The core is surrounded by the shell, which has a wider bandgap, and this improves the efficiency of quantum dots and their yield. By coating this layer, a particle’s capacity and strength can be enlarged, making quantum dots suitable for a variety of applications. Today, the use of quantum dots in
displays has made it to high-quality prototypes amongst established tech companies like Samsung, Sharp and TCL.
EL-QD Electroluminescent quantum dots (EL- QDs) are a promising display technology
that harnesses the electroluminescence of quantum dots to generate light. Their natural light qualities, coupled with the tiny particle size, makes quantum dots a great choice for high-quality, realistic display screens. Their RGB colours are extremely pure and provide an excellent colour gamut required by various display applications. Unlike conventional LEDs or quantum
dot colour converters (QDCCs), where blue LED is used to energise the quantum dots, EL-QDs emit light as soon as current is applied. In EL-QD displays, quantum dots are
sandwiched between two electrodes, forming a light-emitting layer. When a voltage is applied across the electrodes, electrons and holes are injected into the quantum dot layer, where they recombine and in the process emit photons, or light. The emission colour is determined by the size and composition of the quantum dots, allowing for precise control over the colour gamut. EL-QD can achieve a wider colour
gamut than conventional displays due to their narrow emission spectra and tunable emission wavelengths. Their fast response time is also an attractive feature compared to LCDs and OLEDs. In addition, EL-QDs also have the
potential for higher electroluminescence efficiency compared to organic light- emitting diodes (OLEDs).
12 July/August 2024
www.electronicsworld.co.uk
Photoluminescence Photoluminescence further enchances the light emitted by quantum dots, by producing a much brighter and more colourful light, changing shorter blue light waves to the longer reds and greens. Commercially, Samsung already offers
QD-OLEDs, a technology based on photoluminescent quantum dots, but the company has recently also made a good-quality prototype for a QD-LED screen. Working similarly to QD- OLED, EL-QD uses electroluminescent quantum dots as the emissive layer to generate red, green and blue light, without requiring a separate backlight or colour.
Markets IDTechEx predicts the global quantum dot materials market will reach $550m by 2034, with even higher growth to follow, taking increasing market share from other display technologies. Quantum dots will be found in many sectors as they continue to reshape displays and smart devices with their improving quality. IDTechEx’s has a report titled
“Quantum Dot Materials and Technologies 2024-2034: Trends, Markets, Applications”, which explores current and future applications for quantum dot technology.
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