While QD Vision has been more publicly focused on photoluminescence (PL) or optical stimulation of its quantum dots in LED-based solid-state-lighting (SSL) applications, the company is also working on electroluminescence (EL) or electrically-stimulated applications. The company is partnering with plastics and chemistry specialist Solvay to develop a printable platform for EL display and general illumination applications.
QD calls the EL concept a quantum dot LED (QLED), and the similarity to the organic light-emitting diode acronym (OLED) is probably no coincidence. Long term, QD Vision believes that quantum dots make a better choice in planar lighting than the organic emissive material in OLEDs – in terms of better light output, a richer color gamut, and a simpler manufacturing process.
QD Vision is in the earliest of stages of commercial products based on quantum dots. The company is supplying the technology to Nexxus Lighting for use in an LED retrofit light bulb. But the company has been working on EL applications behind the scenes primarily driven by government contracts.
The PL-centric technology does deliver higher light output today, but may not in the future. QD Vision CTO and co-founder Seth Coe-Sullivan said, “Today we are getting the highest lumens per watt out of photoluminescence systems that are excited by blue LEDs. Long term the potential benefit electroluminescence does have is a fundamental advantage in terms of generating light most efficiently.”
Clearly the company is also drawn to the potential market size of the OLED space. Coe Sullivan said, OLED, as an industry, is looking at a $1 billion market this year.” Moreover the technology is still in the earliest of stages as Coe-Sullivan points out that the ecosystem is just forming to fully support OLED commercialization.
The Solvay announcement is the first public step by QD Vision to develop a QLED ecosystem. Of course QD Vision is a relatively small startup company trying to attack an entirely new technology. But QD Vision sees the QLED technology as sharing much of the technology developed for OLED manufacturing with the added advantage that the emissive quantum dots can be printed. About Solvay, Coe-Sullivan said, “The reason it made sense for us to partner with them is their focus on printable electronics.”
”The other key is that the OLED industry exists,” said Coe-Sullivan. “We’re not having to convince people that EL would make for a great display or lighting technology.” The point is that diffused planar lighting is an attractive option both in general illumination and displays.
”We’re just showing them that using quantum dots as the emissive material has performance, lifetime, and cost benefits,” said Coe-Sullivan. “When our performance was an order of magnitude worse than OLEDs, it was hard for people to make that leap. Today we are catching up quickly. Our performance isn’t going to plane out at OLED performance. The lines are going to cross. Our performance is going to be significantly higher.”
We will have to wait and see when or if the quantum-dot EL platform bests OLEDs in light output. The manufacturing story, however, seems more clear cut. Especially in large display panels, companies have struggled to develop commercially viable OLED manufacturing lines. The printable EL approach should face no such challenge.
Still, QD Vision is several years away from commercial EL products. The company did demonstrate a 4-inch-diagonal monochrome display at the SID conference this year. But the company needs to add more partners to the QLED ecosystem and further refine the efficiency of the emissive material before commercial products debut.