Meet QDEL, the backlight-less display tech that could replace OLED in premium TVs

What comes after OLED?

 

With OLED-equipped TVs, monitors, and other gadgets slowly becoming more readily available at lower prices, attention is turning to what the next landmark consumer display tech will be.

 

Micro LED often features in such discussions, but the tech is not expected to start hitting consumer devices until the 2030s. Display makers are also playing with other futuristic ideas, like transparent and foldable screens. But when it comes to technology that could seriously address top user concerns—like image quality, price, and longevity—quantum dots seem the most pertinent at the moment.

 

Quantum dots are already moving in the premium display category, particularly through QD-OLED TVs and monitors. The next step could be QDEL, short for "quantum dot electroluminescent," also known as NanoLED, screens. Not to be confused with the QLED (quantum light emitting diode) tech already available in TVs, QDEL displays don't have a backlight. Instead, the quantum dots are the light source. The expected result is displays with wider color spaces than today's QD-OLEDs (quantum dot OLEDs) that are also brighter, more affordable, and resistant to burn-in.

 

It seems like QDEL is being eyed as one of the most potentially influential developments for consumer displays over the next two years.

 

If you’re into high-end display tech, QDEL should be on your radar.

What is QDEL?

You may know QDEL as NanoLED because that's what Nanosys, a quantum dot supplier developing the technology, calls it. QDEL has gone by other names, such as QLED—before Samsung claimed that acronym for LCD-LED TVs that use quantum dots. You may also see QDEL referred to as QD-EL, QD-LED, or EL-QD. As the alphabet soup suggests, there are still some things to finalize with this tech. This article will mostly use the term QDEL, with occasional references to NanoLED.

 

If none of those names sound familiar, it's probably because you can't buy any QDEL products yet. Suppliers suggest that could change in the next few years; Nanosys is targeting 2026 for commercial availability.

 

That timeline seems pretty ambitious, though, considering the limited number of prototypes we've seen and the limitations still facing QDEL (more on that below). But even if we don't see QDEL for a while, there are reasons to keep an eye on the tech.

 

David Hsieh, senior research director for displays at research firm Omdia, told me via email that when it comes to consumer gadgets, he expects QDEL will most impact TVs, PC displays, and the automotive industry. If commercialized and mass-produced, QDEL can have a cost-to-performance ratio better than that of OLED, but it would still struggle to compete with LCD-LED on a cost basis.

 

A 2023 whitepaper (PDF) from Nanosys and manufacturing partner Sharp Display describes an inkjet printing manufacturing process that is applicable to QDEL monitors and TVs. The photolithography process is reportedly harder because quantum dots get damaged in the process, but it can expand QDEL applications to include tablets, laptops, smartphones, wearables, and AR/VR products. Jeff Yurek, Nanosys' VP of marketing, confirmed to me via email that Nanosys expects to see QDEL products made with photolithography come to market first.

The backlight-free wonder

Today's OLED screens use OLED material as their light source, with QD-OLED specifically applying quantum dots to convert the light into color. In QLED, the light source is a white backlight; QDEL displays apply electricity directly to quantum dots, which then generate light.

 

 

QDEL uses a layer of quantum dots sandwiched between an anode and cathode to facilitates the flow of electricity into the quantum dots.

 

 

QDEL displays have pixels made of a red quantum dot subpixel, green quantum dot subpixel, and—differing from today's QLED and QD-OLED displays—blue quantum dot subpixel. QDEL displays use the same quantum dot cores that QD-OLED and QLED products use, Nanosys' Yurek told me, adding, "The functionalization of the outer layer of the [quantum dots] needs to be changed to make it compatible with each display architecture, but the cores that do the heavy lifting are pretty much the same across all of these."

 

Because QDEL pixels make their own light and can therefore turn off completely, QDEL displays can deliver the same deep blacks and rich contrast that made OLED popular. But with the use of direct-view quantum dots, stakeholders are claiming the potential for wider color gamuts than we've seen in consumer displays before. With fewer layers and parts, there are also implications for QDEL product pricing, longevity, and even thinness.

QDEL in action

You can't buy anything with a QDEL screen right now, but companies have demonstrated prototypes over the past few years. The latest update on the anticipated technology came during the CES trade show in January, when Sharp Display demoed two prototypes to a small number of attendees. One screen was 12.3 inches and 1920×720. The other prototype represented the first time we've seen QDEL scaled to a size that would be appropriate for products like monitors. However, we don't know the resolution of that 30-inch prototype.

 

Sharp Display ready to make self-emissive quantum dot displays.

 

One of the greatest advancements of these recent prototypes compared to previously demoed QDEL examples is that they were manufactured at atmospheric pressure rather than requiring a vacuum chamber. As CNET reported, this is "a big step toward cost-effective manufacturing."

QDEL advantages

The fact that quantum dots are already being successfully applied to LCD-LED and OLED screens is encouraging for future QDEL products. QDEL stakeholders claim that the tech could bring efficiencies like lower power consumption and higher brightness than OLED. (Research using a prototype device has recorded quantum dot light-emitting diodes reaching 614,000 nits. Of course, those aren't the type of results you should expect to see in a real-life consumer product.)

 

Because of these expected benefits, some display enthusiasts predict that QDEL will one day replace OLED and other premium display panel technologies for high-end consumer devices.

 

There's also hope that QDEL could eventually last longer than OLED, especially since QDEL doesn't rely on organic materials that can cause burn-in. Currently, though, researchers are still working on ensuring that blue and green quantum dot materials can last long enough to make a viable consumer gadget without using cadmium. As it stands, QDEL displays would become noticeably dimmer more quickly than today's OLED displays.

 

But optimists believe QDEL display lifetimes could one day be on par with LCD-LEDs and outlast OLEDs. Nanosys believes blue quantum dot materials can be developed to last longer than blue OLEDs due to challenges in achieving high efficiency and a long lifetime with blue OLED "at the correct wavelength or color," Yurek explained.

 

He continued:

 

Short wavelength light like blue is high-energy... The energy required to produce the deep, short-wavelength blue required by video standards like DCI-P3 is high enough to damage the material used to make the light. This is one of the key reasons that blue OLED lifetimes are shorter than the other colors.

Still, quantum dot emission layer lifetime is perhaps the main bottleneck in QDEL commercialization, Hsieh said, adding:

 

Cadmium-free blue QDs' lifetimes have historically been substantially too short to make commercially viable displays. Nanosys-reported data in 2021 was around 10,000 hours, at least two magnitudes (100x) less than minimally required. However, QD [emission layer] material lifetimes have been improving rapidly in recent years and some leading companies will announce 'breakthrough” results soon.

Yurek said that there should be announcements on related developments at the SID Display Week conference in May.

What about Micro LED?

Micro LED has many of the benefits of OLED, including individually emissive pixels for theoretically infinite contrast. And like QDEL, Micro LED shouldn't be as susceptible to burn-in as OLED and can get brighter than OLED.

 

Micro LED is kind of here today. If you have six figures to spend on a TV, you can get a huge Micro LED set from the likes of Samsung or C Seed. Manufacturing challenges in scaling the tech down to common TV sizes in a reliable, affordable fashion have made it unattainable for most, though.

 

Yurek said that it should eventually be possible to manufacture QDEL cheaper than Micro LED, as well as OLEDs and LCD-LEDs. But until we see this in action, we'll have to take that with a grain of salt.

 

QDEL is purportedly manufacturable using the same machines and facilities currently used to make LED displays. Additionally, while QDEL and Micro LED both rely on crystalline inorganic semiconductor materials, those materials are processed differently when making a QDEL versus a Micro LED display, with the latter featuring distinct challenges.

 

We're decently far from knowing what image quality will look like in actual QDEL products and how much tech brands will end up investing to bring QDEL to favorable products. But display experts I spoke with are expecting similar image quality to Micro LEDs, plus more colors. According to Eric Virey, principal displays analyst at Yole Intelligence, QDEL should also bring enhanced "color purity" compared to OLED.

 

Both Micro LED and QDEL consumer products should be brighter than OLEDs, but Virey thinks the brightness advantage will ultimately go to Micro LED products since they "can be driven very hard without damaging them."

 

Some suspect QDEL might be more immediately impactful than Micro LED because of the delays that Micro LED has encountered in seeing adoption in a mainstream product. For example, in March, Mark Gurman cited anonymous sources in Bloomberg saying that Apple had given up on making an Apple Watch and potentially other gadgets with Micro LED due to price and complexity. This was after investing years and what Virey estimated was billions into the effort. Gurman's report said that Apple would continue relying on OLED for its smartwatches and would potentially look into new partners for going down the Micro LED road again.

 

By contrast, though, Samsung in September reiterated its focus on Micro LED as the future of premium TVs.

 

It's feasible that after some years, QDEL, Micro LED, and OLED will all be readily available. In this scenario, Yole's Virey sees all three being potentially competitive for laptops and tablets. QDEL could beat out OLED for premium TVs, as could Micro LED if costs ever came down, Virey said, adding that TVs are probably the "priority target" for QDEL applications. But potential advancements to OLED, like those around brightness or burn-in risk, could improve the tech's competitiveness in consumer devices.

 

Virey thinks QDEL will have a somewhat easier path to delivering its expected image quality benefits to consumer displays at a reasonable cost than Micro LED. He expects an exciting, tight race "over the next couple of years," though.

 

OLED should continue to dominate smartphones, due to the need for high pixel density, which would be a challenge to achieve with QDEL because of its printing process, according to Virey. He added that this process is "good enough for TVs, possibly laptops and tablets, but it’s challenging to improve it to smartphone levels." Smartphones are "by far the most difficult application" for Micro LED due to cost restrictions, Virey said.

 

Interestingly, when the dust clears, Yurek thinks QDEL will be considered the new king of premium displays:

 

I also expect both Micro LED and NanoLED to be positioned as more premium than OLED, given higher potential brightness and durability. All three technologies deliver great experiences, though. So manufacturing and cost will be the key differences. NanoLED promises to be easier to make than either OLED or MicroLED. This is why I think NanoLED will be the ultimate display technology in the long term.

Omdia's Hsieh is less confident about shoppers having both Micro LED and QDEL as options for premium displays. "At this stage, it is still hard to say if Micro LED and QDEL will coexist or not. It will have to be justified by QDEL’s production scale and cost after it enters the commercialization stage... by 2025 to 2026," he said.

 

To make Micro LED displays, Micro LED chips are grown epitaxially on semiconductor wafers. Through a pick-and-place process, thousands of Micro LED chips are transferred to a substrate. Doing this in a way that's reliable, fast, and comparably priced to the manufacturing processes of other display types has proven challenging, and these obstacles have limited Micro LED availability for years.

 

QDEL displays, meanwhile, could be made using the same photolithography process that facilities already use for making various electronic devices and flat-panel displays, including LCD-LEDs. That also means it should be simple enough to make QDEL displays that scale up to the largest consumer TVs available today.

 

Yurek explained:

 

QDs [quantum dots] for NanoLED are solution-processed. Being able to produce semiconductors at huge scale in chemical processing equipment enables us to fabricate precise optical emitters at extremely low-cost compared to fabs. We once calculated it would take 50 square-meters of wafer area to produce 1 gram of QDs if we used traditional semiconductor manufacturing.

 

Those QDs in solution can then be functionalized into inks or photoresists for patterning on displays by inkjet printing or photolithography. The goal is to be able to do this in standard atmosphere without needing to put the whole display inside a vacuum (as you must for highly sensitive OLEDs).

That said, there remain challenges in figuring out how to optimize and scale the manufacturing process for QDEL, whether it's photolithography or inkjet printing.

QDEL availability

"We are targeting 2026 for commercial readiness on the materials side in our public roadmaps. When consumers get their hands on the technology depends on the brands and specific products they want to launch," Nanosys' Yurek told me.

 

That's encouraging, but it doesn't give a firm timeline for when one might actually be able to buy a QDEL TV, and I wouldn't be surprised to see the commercial readiness date pushed back. Even if Nanosys were ready to sell to other brands, there are a lot of other pieces that have to fall into place before people can buy a product with direct-view quantum dots. And early products may not meet expectations, as is sometimes the case with emerging tech.

 

So what comes after OLED? There are several ideas—including just more and better OLED. But the jury, which includes researchers and commercial firms in R&D, tech brands, and ultimately users, is still out. And it will be years before a decision is reached.

 

While we wait, it's easy for those of us interested in exceptional image quality at more attainable prices to root for QDEL.