11/04/24

Quantum dots – The future of Display Technology

Evolution of Display Technology

The display technology came a long way since the introduction of the first TV set in October of 1925 and then the introduction of first commercial LCD and plasma display TV in the early 80’s. Until emergence of OLED, a technology wars between LCD and Plasma polarized the community and consumers. One technology has been praised by low cost and weight, whist plasma has been an epitaph of vivid colors and perfect black representation on screen but paid in full by increased power consumption . The latter has been found a dead end once breakthroughs in LCD technology were achieved. Today OLED type displays offer similar or better contrasts, color representation, resolution and even black with selective pixel illumination, and with the progress on the scale of image quality and fidelity the price and power consumption has risen. This opened up a niche for the quantum dot display in mainstream for great quality displays but with low power consumption and lower cost but more importantly allows for application in portable wearable devices with extremely long battery life, retaining a high quality of image.

The Science Behind Quantum Dot Displays

Quantum dots technology is a peculiar case where the adjective for technology refers to an physical phenomenon that is actually connected with the technology. Quantum display works in a similar fashion as laser does, an LED light excites electrons of a particle with size of couple of nm to a higher energy level and once the electrons return to its initial state and releases a packet (or a quant) of photons with a specific wavelength. The trick is to obtain particles- quantum dots, which will produce specific wave lengths of photons, manifesting in a specific colors. This enables the engineers to design a quantum dot screen without filters for specific colors, allowing for bright and vibrant hues, again with reduced power consumption. For manufacturing of the particles either a colloidal synthesis or plasma synthesis can be used. The former is a cost-effective option and require very accurate and precis controlling of the temperature, concentration of monomers in the solution. The latter is a nonthermal process of gas-phase, that relies on energetic surface reactions. Once the material is ready- obtained by whichever method, the materials need to be dispensed to form an actual quantum display. Typically the solution is to use contact printing method, but XTPL and its UPD offer a way to fill microcavities in extremely precise manner, the 1µm nozzle can dispense the material in femtoliters.

Advantages and Applications of Quantum Dot Displays

QD display offer much brighter representation, improved gamma and contrast that is not attainable in the older IPS/LCD technology. The advantages come from the difference in the way the display being projected from the screen when comparing to the legacy LCD technology. The first area of improvement is the backlight, although still necessary the requirement for white illumination is mitigated by nature of emission. As described in the previous paragraph, the color is emitted by excitation of the semiconductor particles, so the backlight does not need to be of a specific wavelength and be filtered (which reduces brightness and forces higher intensity backlight which in turn increases power consumption !). Then, once photons are emitted, they are very specific in terms of wavelength – color, so another filter is reduced from the system- a filter that will affect the hue of the requested color and would negatively affect the brightness of the picture displayed. Apart of the traditional area of application – quantum dot led TV display – quantum dot screens are being actively considered in the AR/VR market. The lower power consumption is a selling point in such application as it would allow for more compact packaging improving the experience cordless applications without decreasing image quality. A novel display of 2,6µm thickness has been developed as far as 2015 by IBS’s Center for Nanoparticle Research. It had such a low voltage requirement that it could be operated when attached to human skin.

Challenges in Quantum Dot Display Production

Despite clear advantages of quantum dot displays there are some limitation in applying this technology – mainly the elements used in production and manufacturing of quantum materials. One example is cadmium – used in ultra-thin display mentioned above, which will have to be changed if a commercialization of this invention. Metallic compounds like cadmium selenide, are strictly regulated by RoHS and REACH through an exemptions which were prolonged. Another compound is Indium Phosphide which is on a priority list to be closely monitored and restricted in the near future. Manufacturing of the QD displays is at itself a nontrivial task as it is influenced by factors like: solution concentration, solvent ration, QD size distribution and QD aspect ratio which have to be precisely monitored.

The Future of Quantum Dot Technology

The future of quantum dotes brings numerous unknowns but certainly what is expected is that we will witness new areas of implementation of quantum dot displays. Not only the aforementioned new technologies like AR/VR or flexible and ultra-thin wearable display which already show capabilities of the technology. Currently the displays are proven to be capable of depicting true natural colors. What is actually interesting to experience in the near future is to see advancements in manufacturing techniques like the UPD from XTPL which would open new quality in quantum displays and potentially help in scalability. New elements are researched to satisfy stringent requirements of the environmental regulations in the EU. Finally reduction in cost, and further expand in the niche to see how resilient qd displays will be against the new emerging technologies. The prospective of the technology is unquestionable, and we already see adoption of the quantum dot, not only for the consumer electronics but also in new potential areas like photovoltaic and biomedical imaging which were not discussed in this article. To fully unlock the inherent benefits of quantum dots the industry needs to invest, most likely in collaboration with academia, into maturing this innovation.