Ching Wan Tang — "Father of OLED", First Chinese Kyoto Prize Laureate, and His Laboratory at HKUST

# Ching Wan Tang — "Father of OLED", the First Chinese Kyoto Prize Laureate, and His Laboratory at HKUST

In a nutshell: Ching Wan Tang (born 1947 in Yuen Long, Hong Kong) is a Chair Professor jointly appointed across three departments at The Hong Kong University of Science and Technology (HKUST): Electronic and Computer Engineering, Chemistry, and Physics. He is the scientist who invented the double-layer organic electroluminescent diode at Eastman Kodak in 1987^※ (OLED), becoming the first Chinese scientist to receive the Wolf Prize in Chemistry (2011)^※ and the first Chinese scientist to receive the Kyoto Prize in Advanced Technology (2019)^※. His seminal 1987 paper has been cited over 18,500 times^※ (Google Scholar count, at the time of compiling this article), laying the cornerstone for the modern display industry.

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# Who is Ching Wan Tang? Why is he called the "Father of OLED"?

Ching Wan Tang was born on 23 July 1947^※ in Yuen Long, British Hong Kong, and grew up in a tiny rural community of only twelve households, where he worked in the fields planting rice seedlings and farming as a young boy^※. Reportedly, he once built a simple weeding tool from scrap wood and nails as a child, to improve his efficiency when pulling weeds in wet paddy fields—arguably his first "invention"^※, forming a piquant contrast with his later career, which would upend the global display industry. He received his primary education at a local village school, then attended Yuen Long Public Secondary School and Queen's College for his secondary schooling. He earned a BSc in Chemistry from the University of British Columbia, Canada, in 1970^※, and completed his PhD in Physical Chemistry at Cornell University in 1975^※. It was precisely this cross-disciplinary training in chemistry and physics that later enabled him to break through the technical bottlenecks of organic electronics from two dimensions simultaneously—materials and devices.

His designation as the "Father of OLED" stems from a groundbreaking paper, Organic Electroluminescent Diodes, published in 1987^※ (Applied Physics Letters, Vol. 51, No. 12, pp. 913–915), co-authored with Steven Van Slyke at Eastman Kodak Research Laboratories. The device achieved high-brightness emission exceeding 1,000 cd/m²^※ at a driving voltage below 10 volts^※—an order-of-magnitude leap compared to earlier organic electroluminescent devices, which had required thousands of volts. This paper has become one of the most highly cited papers in the history of Applied Physics Letters^※, with over 18,500 citations^※ (Google Scholar count).

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# Thirty-one Years at Kodak: The Route from Organic Solar Cells to OLED

Ching Wan Tang joined Kodak in 1975^※, initially focusing on organic photovoltaic (OPV) device research. He spent several years in the lab improving the photoelectric conversion efficiency of organic heterojunction solar cells, eventually raising the efficiency of the initial devices from roughly 0.2% to about 1%^※, and filed a related patent in 1979^※. However, a gaping chasm remained compared to the over-10% efficiencies of inorganic solar cells at the time, and the research was subsequently shelved.

This "detour" brought an unexpected dividend. While studying the heterojunction bilayer structure, Tang discovered that the same donor-acceptor stacked design, when electrified, could not only separate photo-generated charge carriers but also cause the organic layers to emit visible light efficiently. He pursued this direction, securing his first OLED device patent in 1982^※, achieving an external quantum efficiency of about 1% at a mere 5 volts^※—at a time when every known organic electroluminescent device required roughly 2,000 volts^※ to operate.

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# The 1987 Bilayer Device: What Technical Innovation Moved OLED from the Lab to Industry?

In the 1987 device^※, Tang and Van Slyke adopted a stacked double-layer organic thin-film structure: an aromatic diamine hole-transport layer on the bottom, and a tris(8-hydroxyquinoline)aluminum (Alq₃) layer on top, which served as both the electron-transport layer and the emissive layer. The two material layers independently optimised the injection and transport of holes and electrons respectively, enabling efficient recombination and light emission at the interface, thus boosting luminous efficiency to over 1%^※—roughly an order of magnitude beyond the prior state of the art.

In 1989^※, he further demonstrated that doping fluorescent guest molecules into the emissive layer could tune the emission colour via host-guest energy transfer, opening the technological pathway to full-colour OLED displays. These two pieces of work established the fundamental paradigm for modern OLED devices, which remains the core architecture for both academic research and industrial mass production today.

The table below outlines Tang's key technological milestones at Kodak:

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# The Wolf Prize in Chemistry (2011): Why Does This Award Carry Special Weight?

In 2011^※, the Israel-based Wolf Foundation awarded the Wolf Prize in Chemistry that year to Ching Wan Tang, Stuart A. Rice, and Krzysztof Matyjaszewski, for, in the foundation's words, "exploring the nature of organic solids and their energy landscape, structure and dynamics, and for creating new ways to make organic-based materials of all kinds, from polymers, to devices that harvest the sun's energy and that light up our lives."

Among the three laureates, Tang's core contribution was founding the two most dynamic research fields in organic materials: the organic light-emitting diode (OLED) and organic photovoltaics (OPV)^※. The Wolf Prize is widely regarded in scientific circles as one of the highest academic honours second only to the Nobel Prize^※; a notable proportion of its past recipients later became Nobel laureates. Ching Wan Tang was the first Chinese scientist ever to win the Wolf Prize in Chemistry^※. The three laureates shared a prize of US$100,000^※, with the award ceremony held at the Knesset, Israel's parliament, on 29 May 2011^※.

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# National Inventors Hall of Fame (2018): What Does Being Inducted Alongside Van Slyke Represent?

In 2018^※, Ching Wan Tang and his collaborator Steven Van Slyke were simultaneously inducted into the National Inventors Hall of Fame in the United States, recognising their joint invention of OLED technology under U.S. Patent No. 4,356,429^※. Alongside the Nobel Prize and the U.S. National Medal of Technology and Innovation, the National Inventors Hall of Fame constitutes one of the United States' highest official systems of recognition for invention and innovation; the criteria for admission require that the invention has "had a widespread and sustained impact on society."

At the time of his induction, Tang already held over 80 patents^※. In an interview, he remarked: "What's most important is that you always experiment with ideas. That's the key to all inventions." This scholarly attitude ran through his entire career—from the organic solar cell research that initially met with little optimism, to the OLED invention that later fundamentally reshaped the display industry.

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# The Kyoto Prize (2019): What Is the Historic Significance of Being the First Chinese Laureate?

On 14 June 2019^※, the Inamori Foundation announced that the 2019 Kyoto Prize in Advanced Technology (Engineering Sciences and Technology category)^※ would be awarded to Ching Wan Tang, for his "pioneering contributions to the birth of high-efficiency organic light-emitting diodes and their applications." Since the Kyoto Prize was established in 1985^※, Tang is the first person of Chinese descent to receive this honour^※. Each laureate receives a diploma of ambassadorial rank, a 20-karat pure gold medal, and a cash prize of 100 million yen^※ (roughly over HK$7.5 million at the time); the award ceremony was held on 10 November 2019^※ in Kyoto, Japan.

The official Kyoto Prize citation specifically noted that Tang's development of the double-layer device structure "led to substantial improvements in their efficiency and reliability; and led to the practical use of OLEDs and their widespread use in displays and lighting." On the eve of the award, Tang offered this reflection on the value of his scientific work:

"Nothing is more satisfying for a scientist than to come up with an invention that billions of people benefit from every day." —Ching Wan Tang, 2019^※

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# What Position Does Ching Wan Tang Hold at HKUST? What Are His Research Directions?

In 2013^※, Ching Wan Tang left the University of Rochester and formally joined The Hong Kong University of Science and Technology, where he was appointed Bank of East Asia Professor at the HKUST Jockey Club Institute for Advanced Study (IAS)^※, concurrently holding the title of Chair Professor spanning three departments: Electronic and Computer Engineering, Chemistry, and Physics. For one person to straddle three disciplinary departments is unusual even by HKUST standards, a reflection of organic electronics' inherently deep cross-disciplinary nature.

Tang's research at HKUST centres on organic semiconductor materials and devices, extending and deepening the core research directions he pursued during his Kodak years. In his capacity as Research Team Leader, he participates in the Partner State Key Laboratory of Advanced Displays and Optoelectronics Technologies, approved by China's Ministry of Science and Technology in September 2013^※. This laboratory, jointly established by HKUST and Sun Yat-sen University, focuses on five major research directions: oxide thin-film transistor arrays, third-generation organic light-emitting diodes, liquid crystal displays, video signal processing, and integrated circuit design, with green, energy-saving active-matrix OLED (AMOLED) technology as its core objective. It brings together a total of 23^※ senior faculty and research staff from HKUST's School of Engineering and School of Science.

During his time at HKUST, Tang has also been active in academic outreach. He has delivered invited lectures at institutions including the Hong Kong Academy of Sciences and the Chinese Academy of Sciences, systematically recounting the history of the OLED invention and the latest advances in organic solar cells (organic photovoltaic efficiency by that point had approached roughly 10%^※). He is also a Founding Member of the Hong Kong Academy of Sciences^※.

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# Major Honours Conferred on Ching Wan Tang

The table below summarises the major international awards and honours Tang has received to date (data cross-verified against multiple official sources):

In addition, Tang holds numerous industry accolades, including the Kodak Eminent Inventor Award (1994), the Kodak Innovation Award (2000), the American Chemical Society Team Innovation Award (2004), the Holonyak Award (OSA, 2014), the NEC C&C Prize (2018), and more. His total number of patents held exceeds 80^※ (National Inventors Hall of Fame figure, at the time of induction).

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# How Widespread Is OLED Technology Today? What Has Been the Impact of Ching Wan Tang's Work?

The bilayer OLED device Ching Wan Tang invented in 1987 has given rise to a global industry worth tens of billions of dollars^※. Today, the displays in consumer devices used daily—smartphones (such as OLED-equipped Samsung and Apple iPhone models), televisions, laptop computers, and wearables—are mostly based on the OLED or AMOLED technology that traces back to his principles. Compared to conventional liquid crystal displays (LCDs), OLEDs are self-emissive, require no backlight, can achieve true blacks and higher contrast, and allow for thinner, flexible screens; they have gradually become standard in flagship display products.

At the academic level, Tang's impact runs equally deep: the 1987 paper^※ co-authored with Van Slyke has exceeded 18,500 citations (Google Scholar count), making it one of the most foundational single documents in the field of organic electronics and among the most-cited in the annals of Applied Physics Letters. The concept of the organic heterojunction he pioneered applies both to light-emitting devices (OLEDs) and photovoltaic devices (OPVs), allowing two physically inverse processes to share the same material-design logic. This "one platform, two uses" paradigm continues to inspire a new generation of organic semiconductor researchers today.

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