Global Quantum Dots Market Poised for Rapid Growth
Array of Applications Range from Signage to Monitors to TV
By: Jagadish Kumaran, Chair, Public Relations, Bay Area SID Chapter
Liquid Crystal Display (LCD) is currently the dominant technology used in television displays, and represents more than 90 percent of the market. LCDs enabled flat-panel televisions that were slimmer and lighter than cathode ray tubes (CRT) and resulted in the eventual phasing-out of CRTs. Although LCDs steadily gained popularity and market share since its introduction in 1998 and eventually surpassed CRT sales in 2007, other competing technologies such as Organic LED (OLED) have emerged in the last decade that have capitalized on the limitations of LCDs. Quantum Dots have enabled LCD to defend its dominant market position by improving one of the key weaknesses of LCD – its poorer color gamut.
The color gamut is a measure of the entire range of colors that can be depicted on the display - the wider the gamut, the more life-like and immersive are the images that are displayed. The light source in an LCD is the backlight and this light has to travel through several layers in the display stack such as polarizers, color filters, TFT/color filter glass and liquid crystal material that worsen the color gamut of the display. Although this is a known issue with LCD technology, the industry has been making improvements such as the changing of the backlight type from florescent lamp to LED and by improving the quality of the LED backlights. OLED displays have a larger color gamut and better contrast ratio than LCD and is established as a viable technology for mobile phones and tablets. However, OLED adoption for TV displays has been slower than desired: they are harder to manufacture at large sizes and the lower yields make them significantly more expensive than LCDs.
Quantum dots are bridging the color gamut gap between LCD and OLED displays. These semiconductor nanocrystal particles absorb light at one wavelength and efficiently emit that energy at other specific wavelengths that are determined by the size of the dots. When the light from an LCD backlight is channeled through the quantum dots, the redistribution of energy results in more vivid colors and a color gamut improvement of as much as 40-50 percent. Very few nanocrystal quantum dots are required per TV display – about a gram of material is adequate – at incremental added cost to the LCD display. Thereby QD-LCDs deliver color richness, quality and contrast similar to that of OLED, but at a fraction of the price.
QD-LCDs can be constructed using several methods including the insertion of a sheet of film with quantum dot material into the material stack, or by placing a narrow tube containing the QDs in front of the LED backlight. Both of these techniques have been used to mass-produce QD-LCDs in the recent past. QD Vision (Lexington, Mass.) is spearheading the tube approach, while Nanosys (Milpitas, Calif.) is focused on the QD film technology – both are partnering with a number of companies in the TV and display monitor market. Industry giant Samsung, on the other hand – which has abandoned OLED for TVs and fully endorsed QD – is pursuing a third approach: directly applying the quantum dots to the backlight source.
One downside of QD technology has been the use of heavy metals, such as cadmium, to create the dots. These heavy metals are increasingly being restricted around the world. Companies such as Quantum Materials Corp and Nanoco are pursuing other means of creating quantum dots that don’t contain heavy metals.
Although the outlook for QD-LCDs is promising, it is anticipated that OLEDs will continue to co-exist and will be the preferred technology for flexible and curved displays that can’t be easily constructed using glass-based LCDs and for smaller-sized displays used in wearable devices and mobile phones. In the future, quantum dots will be combined with OLEDs, making them even better. Quantum dots are also suitable for numerous other, diverse applications, including solar cells, solid-state lighting, biotechnology and security, to name a few. Consensus among market researchers is that, starting this year, the global QD market is expected to grow by about $1 billion per year over the next decade.
In summary, quantum dots enable LCD technology to hold its dominant market share in applications such as signage, monitors and TV. Although vivid colors are highly desirable, cost tends to trump everything else in consumer markets, and quantum dots enable the well-depreciated LCD factories to keep the high end of the TV market from moving to OLEDs. Quantum dots are expected to become a household name worldwide as manufacturers introduce new consumer products with this technology.