Polarizers and filters in front of the backlight control the amount of light that shines through the stack. LCDs have a backlight, which is usually a white LED. These two technologies are based on different operating mechanisms. Two different display technologies can benefit from the unique characteristics of QDs, namely Liquid Crystal Displays ( LCDs) and Organic Light-Emitting ( OLED) displays. OLED vs LCD Displays - How Quantum Dots can be employed A recent press release by Samsung demonstrates that quantum dot down-conversion layers, together with OLED light sources, will play a dominant role in the display market in the coming years. The narrow emission characteristics of quantum dots enable a much higher color gamut resulting in more vivid colors compared to conventional LCD screens. Quantum dots allow using high efficient blue or UV illumination sources and then down-convert the photons to the desired wavelength. In these displays, quantum dots are used as down-converting materials to modify the background light to the desired color right before the color filters, or they are added to the light diffusor layers which uniformly distribute the background light over the whole display. The most famous brands, are Sony Triluminous and Samsung QLED TVs. The LED can be based on both organic or inorganic materials, and have the quantum dots replacing the emitting layer, the non-emitting layers, or both.īy far, the most important application for nanocrystals are quantum dot enhanced liquid crystal displays (LCDs). Quantum dots can also be used to build light-emitting diodes (LEDs). To now, (spring 2020) the record quantum dot solar cell shows a power conversion efficiency of 16.6%, more than five times larger than the record efficiency 10 years ago. This absorption tuning enables, at least theoretically, higher efficiency solar cells compared to the established silicon solar cells. Quantum dot solar cells, for example, exploit the tunability of the nanocrystal optical bandgap, which allows optimizing the absorption spectrum of the device to the spectrum of the sun. For example, researchers build field-effect transistors (QDFET), single-electron transistors, and other devices.Ĭombined opto-electrical applications are more challenging, but at the same time are able to fully capitalize on the unique properties of quantum dots. Pure electrical applications are also possible by using the semiconducting properties of quantum dots. Depending on the size, the color of the emitted photon can be blue, green, or red. The quantum dots in the solution absorb these photons and emit lower-energy photons. The solutions shown in the figure are illuminated with a high-energy UV-light source. Figure 1 hints at a possible application of these materials, i.e., quantum dots can be used as photon down-converters.
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