Quantum Dots: IDTechEx Research Analyzes Changing and Expanding Application Landscape

Estimated reading time: 8 minutes

Quantum dots (QD) are a success story in displays. The current incumbent mode of integration is film type (enhancement film). The value chain for this is well-established. The technology can be integrated into large displays (TVs) from 27-inches to 98-inches. The improvements in the cost of QD enhancement films, brought about thanks to lower barrier requirements, lower QD costs and higher coating yields have made possible a wide range of prices $370 (55-inch) to $3k (82 to 90-inch). ​Some are now beginning to even argue that the net cost of QD enhancement film implementation can be near zero if highly bright QDs help to make brightness enhancement films redundant.

The technology, however, is experiencing rapid change. As analyzed in the report “Quantum Dot Materials and Technologies 2019-2029: Trends, Markets, Players,” the technology roadmap for QDs in displays include on-glass QDs, in-pixel (or color filter) QDs on LCD or OLEDs (inkjet or photopatterned), as well as emissive QLEDs. The QDs are also finding applications beyond displays in lighting, NIR/SWIR QD-Si hybrid photosensors, agriculture color conversion films, security tagging and so on.

In this article, IDTechEx Research provides a brief look at multiple key applications. This analysis is extracted from their report “Quantum Dot Materials and Technologies 2019-2029: Trends, Markets, Players.” This report provides a detailed technology analysis and roadmap. It provides market forecasts, in mass and value, segmented by 11 applications. It provides an overview of all the key players in the industry. It also offers a critical assessment of existing and emerging material options, material challenges, and material innovation and development opportunities.

The way QDs are integrated into displays is changing. Some are seeking to evolve QD films into QD-on-glass implementation. Here, the QD is coated directly on the light guide plate and is, on one side, thin-film encapsulated. This will reconfigure the value chain at the expense of roll-to-roll (R2R) filmmakers. It will lead to thinner solutions since the additional substrate is eliminated and the QD layer itself can be made thinner. Not everyone will adopt this in-house solution.

Quantum Dots in Displays: Roadmap

The next evolution is for QDs in-pixel color converters (often referred to as QD color filters or QDCFs). The red and green QDs can be applied to sub-pixels by inkjet or via photolithographically-patterned QD photoresist. This will require high blue absorbance to ensure color purity and thin layers. It will also require good dispersion at high loading levels into the resin.

The QDs must also survive the process. In the case of photopatterned resists, the QD must survive the soft bake, the etching, the hard bake and so on, with little or no quantum yield, FWHM, or emission wavelength change. In the case of inkjet, the QDs should be formulated into printable-inks, must print well within the black matrixes and must survive the curing (most likely thermal) process. Progress here is strong. Material suppliers, in close collaboration with QD suppliers, have developed good QD photoresists and inkjet inks. This is in an advanced stage.  

The QDCF can be applied both to LCD and OLED. In the case of the former, system-level challenges exist. In particular, the need for an in-cell polarizer is a major challenge, requiring technology development and new process adaption. For the latter, the red and green QDs are to be inkjet-printed atop a continuously applied (un-patterned) blue OLED (now fluorescent, but this might change in time to TADF for efficiency gains if and when TADF or hyper TADF becomes commercial). The use of printing here may give a cost-effective process for achieving high-quality, large-sized QD-OLED hybrid displays that exceed the performance and cost of WOLEDs, which utilize standard color filters. The use of printing will also represent critical strategic learning towards the ultimate goal of solution-processed emissive QLEDs.

QLED: Ultimate Display?

Indeed, QLEDs are a major long-term topic of R&D. They can enable thin/flexible high-contrast, efficient, and wide color gamut displays. The challenges on the way, however, are still many. As such, it will be some years before we see full-color commercial products. A new QD toxicant-free chemistry is likely to be needed for efficient blue at the desired wavelength. The green and red InP QDs will likely require better shell coverage and graded alloying to eliminate internal CTE mismatches. The right organic HTL with a sufficiently deep valence band will be needed to ensure a good charge balance. The ETL, likely based on a printable metal oxide nanoparticle, will need to be optimized. And, of course, all production and scale-up processes will be engineered too.

Today, most display firms are active. The rate at which champion results are improving on all fronts (blue EQE, luminance, lifetime at reasonable nits, etc) is high. This is an area to closely watch, as it represents extensive innovation and development opportunities. To learn more, please see the IDTechEx Report “Quantum Dot Materials and Technologies 2019-2029: Trends, Markets, Players.”

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