Title: Despite Challenges, QD Vision Laid the Foundation for Quantum‐Dot Displays
Abstract: Information DisplayVolume 38, Issue 3 p. 42-44 PathwaysFree Access Despite Challenges, QD Vision Laid the Foundation for Quantum-Dot Displays Prachi Patel, Prachi PatelSearch for more papers by this author Prachi Patel, Prachi PatelSearch for more papers by this author First published: 03 May 2022 https://doi.org/10.1002/msid.1306AboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat SONY ANNOUNCED THE WORLD'S FIRST QD-OLED TV IN JANUARY. THE PANELS will combine the best of quantum dots (QDs) and organic light-emitting diodes (OLEDs)—display technologies that have thus far been rivals. The paper-thin panels will have a wide color gamut, deep blacks, wide viewing angles, and better power-efficiency than traditional OLED and LCD displays. However, this isn't Sony's first foray into QD display technology. They were the first company to make and sell a QD TV in 2013, albeit just for a year. Those panels used colloidal QDs developed by QD Vision, an MIT spinoff based in Lexington, Massachusetts. Samsung, which acquired QD Vision in 2016, is now making the new QD-OLED panels for Sony. Indeed, QDs might not have been part of displays if not for the pioneering materials technologies developed by QD Vision's co-founders Jonathan Steckel and Seth Coe-Sullivan. Vision for the Future QD Vision's story began in 2001, when Steckel and Coe-Sullivan met as graduate students at MIT. Visiting chemistry professor Moungi Bawendi's laboratory, Steckel saw vials filled with liquids that glowed brightly in all colors of the rainbow. "When I saw those colors, it was a game changer," he says. "They were so pure, so intense, so saturated. It just pulled me in." He knew immediately that he wanted to complete his PhD in QD technology. Meanwhile, Coe-Sullivan, then a second-year PhD student, was working in an electrical engineering lab with Vladimir Bulović trying to use QDs in light-emitting devices. At the time, QDs, which are semiconductor nanocrystals, were being considered mainly as down-convertors, where they would absorb blue light from highly efficient gallium-nitride LEDs and convert them to other lower-energy light wavelengths. Coe-Sullivan and Steckel teamed up, wanting to try something new. "Our focus, while at MIT, was putting electric current into these materials and getting light out," Coe-Sullivan says. They did that by making OLED-like devices that, instead of organic materials, used QDs sandwiched between thin films. When electrically charged, the devices glowed pure bright colors, although these early devices were unstable, with emission lasting only minutes. By tweaking chemistries, particle dimensions, and device stacks, they made bright, efficient red, green, blue (RGB) and infrared-emitting QD-LEDs, or QLEDs. The idea of a startup emerged at a party where Coe-Sullivan, who also was pursuing a minor at the MIT Sloan School of Management, met MBA student Greg Moeller. The two started crafting a business plan that evening. Coe-Sullivan's 2002 Nature paper1 on QLEDs with Professors Bulović and Bawendi already had made a splash and caught the attention of other researchers and venture capitalists (VCs). Despite having the pressure of completing PhD research and thesis requirements, the students found themselves speeding ahead with the spinoff (Fig. 1). Fig 1Open in figure viewerPowerPoint Jonathan Steckel and Seth Coe-Sullivan present their work on tunable quantum-dot (QD)-LEDs, or QLEDs, at a conference in 2002. In 2004, Coe-Sullivan, Bulović, Moeller, Steckel, and mentor Joe Caruso launched QD Vision. Over the next year, Coe-Sullivan and Steckel fervently worked on their theses while making investor pitches and writing grant proposals for funding. "We needed to preserve IP rights," Coe-Sullivan says. "It got us talking to VCs and socializing." Not an Easy Road Challenges abounded for the team on the technical and business sides. They were making small prototype displays, but the biggest hurdle they faced was device stability. "To commercialize display technology, [it] has to have reliability and lifetime," Steckel says. "One of the biggest pieces was improving efficiency but also showing that the technology was stable. We spent a lot of time understanding why we were seeing degradation and understating where it was happening—whether it was at the quantum dot surface, the ligands, or the interface. Why were the devices dying within hours instead of thousands of hours, like organic LEDs?" The issue proved difficult to surmount, and by 2007, with QLED reliability at a standstill, Coe-Sullivan and Steckel started thinking about other marketable applications for their brilliantly colored QDs (Fig. 2). The duo remembers brainstorming ideas over long walks along the Charles River. Fig 2Open in figure viewerPowerPoint QD Vision's QLEDs emitted bright, saturated colors. "Stress breeds creativity," Coe-Sullivan says. "It was a good lesson on selling what you can make versus making what you want to sell. And a great lesson in terms of hitting a moving technology market." And it was a fast-moving market. They first developed a colored keypad backlight for the then-popular Razer phone. But, as luck would have it, the Razer quickly lost market-share after the iPhone's release in 2007. QD Vision pivoted to putting their QDs on blue and white LEDs to produce general lighting products. In 2009, they teamed up with Nexxus Lighting to make an LED lamp that emitted warm white light similar to incandescent light bulbs by passing cool white light from LEDs through a red QD film (Fig. 3). "That's what led us to the idea of putting red and green quantum dots in displays," Steckel says. Fig 3Open in figure viewerPowerPoint A lightbulb made by Nexxus Lighting used QD Vision's QD film (orange plate) to convert cool white LED light to warm white. The timing seemed right. In 2009, the display industry was starting to switch from fluorescent lamps to blue LEDs as the backlight source for LCD displays. Blue LEDs were coated with yellow phosphors to produce white backlights that would pass through RGB color filters. But the color gamut was poor. To solve that problem, QD Vision came up with an innovative backlight solution. They filled glass capillaries with polymer-based solutions of red and green QDs, cured the polymer with UV light to solidify it, and sealed it off. The idea was to put the tubes at the edge of LCD displays, where they could color-convert blue LED light, creating a 50 percent wider color gamut and more vivid images than phosphors. Sony debuted these high-end QD-based LCD displays in 2013, with QD Vision producing the glass tubes at a manufacturing facility in Taiwan. The success was not to last long, though. Only a year later, Sony decided to switch back to phosphor-coated LEDs in their backlights because of newly available narrow-band emissions phosphors. That led to some tough decisions, Steckel says, and QD Vision had to lay off half of their team of 160 employees. Diverging Paths The business loss also brought personal reckoning for Steckel. The display and electronics industries now were actively pursuing QD technology. QD Vision's main competitor, California-based Nanosys, was making QD films for LCD backlights that were garnering the attention of display manufacturers such as Samsung. Steckel wanted to push QD Vision to focus on a next-generation approach, coating QD material directly onto LEDs to create color at individual pixels, but others at the company were not convinced. In late 2014, "Apple came knocking and offered me an opportunity that was impossible to say no to," he says. He left QD Vision to join Apple in Cupertino to lead the development of emerging display technologies, where he became, "the guy for anything quantum dot." He and others at Apple published a patent in 2019 on a hybrid QD-OLED display, where each pixel has an OLED subpixel and a QD subpixel. Steckel soon found himself working with the Apple camera team in Grenoble, France, working on sensors for the iPhone. The sensors today use silicon devices to detect near-infrared light, and Steckel led the charge in leveraging QDs instead. In early 2020, he moved to STMicroelectronics to lead the commercialization of QD-based image sensors. Coe-Sullivan, meanwhile, stayed on at QD Vision until 2016, when Samsung, which had been working on QD electroluminescence technology, acquired the startup for $70 million. He became vice president and chief technology officer at Luminit, a developer of holographic technologies. In 2019, he co-founded NS Nanotech, where he is now CEO and president. The company is developing next-generation nano-LED technology, while also making the world's first solid-state, far-ultraviolet C (UVC) light source for disinfection. Their circuitous paths have led them away from QD-based displays, but the pioneers are proud of the technology they helped develop and its promise. Sony's new QD-OLED TV is using some of the technology they developed, Coe-Sullivan says, but also includes many new innovations. Coe-Sullivan encourages budding entrepreneurs who might be thinking about launching a business to take the plunge. "Take risks," he says "but surround yourself with and hire people who are smarter than you. Innovation is a team sport, and does not come from the top-down." It's also important not to lose focus on why you are pursuing a startup, says Steckel. "Don't start a company because you want to get rich or famous. If you do it out of your passion and desire to change the world instead, you will have so much more fun, and your chances of success will be so much higher." Biography Prachi Patel is a Pittsburgh-based freelance journalist who writes about energy, materials science, nanotechnology, biotechnology, and computing. Reference 1Coe, S., Woo, W.-K., Bawendi, M., & Bulović, C. (2002). Electroluminescence from single monolayers of nanocrystals in molecular organic devices. Nature, 420, 800– 803. CrossrefCASPubMedWeb of Science®Google Scholar Volume38, Issue3May/June 2022Pages 42-44 FiguresReferencesRelatedInformation
Publication Year: 2022
Publication Date: 2022-05-01
Language: en
Type: article
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