On February 2, 2021, the prestigious Queen Elizabeth Prize for Engineering was awarded to five engineers pivotal in the creation and advancement of solid-state lighting technology: LEDs. These light-emitting diodes, known for their high efficiency and reduced energy usage, are now recognized as one of the most effective strategies for combating climate change.

The recipients of the QEPrize—Isamu Akasaki, Shuji Nakamura, Nick Holonyak Jr., M. George Craford, and Russell Dupuis—each boast illustrious careers in the fields of physics and engineering. This honor has been long anticipated, as society has enjoyed the advantages of LED technology for many years.

From automotive headlights and traffic signals to computer displays and emergency lighting in theaters and aircraft, LEDs are ubiquitous in our daily lives. The LED industry alone is valued at over $100 billion and continues to expand, despite the fact that LED bulbs can last up to 25 times longer than traditional incandescent bulbs, underscoring their contribution to sustainability.

Predict was fortunate to conduct interviews with three of the QEPrize laureates: Shuji Nakamura, George Craford, and Russell Dupuis.

Predict: (to Shuji Nakamura) What inspired you to create high-efficiency blue LEDs in 1993?

Shuji Nakamura: In the 70s, 80s, and 90s, it was widely believed within the scientific community that it was impossible to produce highly efficient LEDs when the number of crystal defects exceeded 1 x 10³/cm². However, I successfully fabricated InGaN-based blue LEDs despite the defect density being over 1 x 10?/cm². This led to the development of the first highly efficient blue LED and its commercialization in 1993. Since then, many researchers have sought to understand the efficiency of InGaN-based blue LEDs despite such a high level of defects.

Predict: (to George Craford) Did you always aim for your work on LEDs to reduce human energy consumption for lighting, or was that an unexpected benefit?

George Craford: In 1963, Holonyak predicted the potential of LEDs and lasers for lighting. His demonstration of a bright red LED while immersed in liquid nitrogen at the University of Illinois was truly inspiring and prompted me to pursue work in this area. However, it wasn't until much later that I started considering the energy-saving potential of LEDs.

For 50 years, I led research teams at companies like Monsanto and Hewlett Packard/Philips/Lumileds, focusing on producing the most efficient LEDs possible to ensure commercial success in a competitive landscape. In 1971, we introduced a technology that increased red LED efficiency tenfold, from less than 0.1 Lumen per Watt to 1.0 Lumen per Watt, and created the first yellow LED. An advertisement in the Wall Street Journal touted the future of LEDs in various applications, including automobile headlights, which faced skepticism from other experts.

By 1990 at Hewlett-Packard, we unveiled another innovation that enhanced the efficiency of red, red-orange, and amber LEDs by an additional 10 to 100 times. It became evident that LEDs could replace incandescent bulbs in applications like traffic lights and car tail lights due to their energy savings. I then began contemplating the possibility of using LEDs for white lighting, which required high-efficiency blue LEDs. Multiple laboratories were working on blue LEDs, but their performance was lacking. The introduction of high-efficiency blue LEDs by Nakamura in 1993 marked the beginning of the race toward high-efficiency white LEDs for general lighting.

Predict: (to Russell Dupuis) What do you consider your most significant contribution to LED technology?

Russell Dupuis: Today’s LEDs (as well as advanced solar cells and laser diodes) employ complex structures that consist of various semiconductor materials grown on single-crystal substrates. The predominant method for producing LEDs is metalorganic chemical vapor deposition (MOCVD), a process to which I made significant contributions. I was the first to demonstrate the growth of efficient light emitters (and solar cells) using MOCVD. In collaboration with Prof. Holonyak, I also demonstrated the first high-performance laser diodes and light emitters using intricate ultrathin layers or quantum-well heterostructures, which are now essential in high-brightness and high-power LEDs.

Predict: What prompted your decision to focus on physics and engineering?

Shuji Nakamura: My passion for math and science from a young age naturally led me to choose physics and engineering as my career paths.

Russell Dupuis: My interest in physics, math, and chemistry during high school steered me toward electrical engineering in college, as it integrated these fields in a practical manner. A friend from my hometown who was studying electrical engineering at the University of Illinois also influenced my decision.

George Craford: Growing up in a farming community, my mother was a teacher, and my father worked on the farm. A college friend of my mother, who taught at the University of Chicago's laboratory school, gifted me science books when I was in elementary school. This sparked my interest, and I set up a laboratory in our basement during junior high. After taking high school physics and enjoying it, I decided to pursue it further. I was fortunate to have Dr. James van Allen as a mentor at the University of Iowa, who encouraged me to study solid-state physics at the University of Illinois. After witnessing Nick Holonyak demonstrate a bright red LED in liquid nitrogen, I switched my focus to this exciting field.

Predict: In what areas do you think LED technology should be utilized more extensively?

Russell Dupuis: LEDs should entirely replace fluorescent lamps, as these older lights contain toxic substances and are less efficient. Moreover, LEDs can provide warmer light that can be tailored to align with the human circadian rhythm.

Shuji Nakamura: All types of lighting should transition to LED and laser technologies to minimize energy consumption and combat global warming.

George Craford: While LEDs are already widely used, there is still substantial room for growth in the market. New installations often incorporate a high percentage of LEDs, but replacing existing lighting will take time. In developing nations, LEDs combined with solar cells can illuminate homes after dark, enabling children to study without relying on harmful oil or kerosene lamps. In horticulture, LEDs are increasingly utilized, allowing restaurants to grow fresh produce in-house without damage from transport. Additionally, lighting that follows the circadian cycle could enhance productivity and health. The use of ultraviolet LEDs for water and air purification is also promising, particularly in the face of potential future viral outbreaks.

Predict: Where do you envision LED technology in 20 years, and what might eventually supersede it?

George Craford: While LED technology will become brighter, significant improvements in brightness are unlikely, except potentially in the green spectrum. Quality will likely enhance, especially regarding color control, and costs will continue to decrease. Lasers may take over applications requiring intense light, such as automotive headlights, while organic LEDs (OLEDs) are starting to replace traditional LEDs in displays. High-density arrays of mini LEDs are also being developed for devices like watches, as they are more efficient than OLEDs. As Holonyak stated, LEDs are the ultimate light source, and I see no replacements on the horizon.

Shuji Nakamura: In two decades, far UV-C LED lighting could be ubiquitous for eradicating viruses, including COVID-19.

Russell Dupuis: Holonyak has theorized that LEDs possess a 100% internal quantum efficiency, meaning no other light-emitting technology can surpass them. Future applications will likely see increased use of LEDs for air and water purification as well as in agriculture, particularly in space. While other organic semiconductor LED (OLED) technologies are being explored, their performance for high-power and high-efficiency uses still falls short compared to traditional inorganic semiconductor LEDs. Although OLEDs have their place, they remain fundamentally LEDs.

LED lighting will continue to be a cornerstone of our technology and society, gaining even more significance as it adapts to a broader range of applications. The future is undoubtedly radiant!

Thank you for reading! If you wish to support my writing, consider purchasing my novel “Talisman of Earth” here: https://amzn.to/3rTHS1f