Research Breakthrough

Professor Pi-Tai Chou's team breaks the world record of organic strong luminescence, which will help the development of biomedicine and communication industries. The international research team chaired by Professor Pi-Tai Chou of our center broke through the world record of strong organic luminescence from 840nm to 1000nm in one fell swoop, which will be of great help to the development of biomedicine and communication technology in the future. The research results of Professor Pi-Tai Chou have been officially published on October 10, 2022 in the top international optoelectronic journal "Natural Optoelectronics". At the same time, it can reduce the absorption loss of information transmission and improve the performance of optical fiber technology. Near-infrared (NIR) wavelength ranges from 1000 to 1700 nanometers, commonly known as the second infrared region (NIR(II)). In the field of biomedicine, it can pass through skin tissue and blood vessels for deep imaging detection or initiate drug action, which is also important. Primary light source for wearable biomedical products such as oximeters, phototherapy patches.

Organic molecular materials have a significant thermal quenching effect in the energy gap law in the second infrared region. Theoretically, their light emission yield is close to zero, and they are unlikely to be suitable for the application of light emission in the second infrared region. Therefore, how to make organic molecules have strong light emitting properties in the second infrared region has long been considered an impossible task in international optoelectronic research. In order to make the impossible possible, Professor Pi-Tai Chou's team started from the theoretical basis in 2017, thinking that if the coupling is an inevitable law, then whether other methods can be used to effectively reduce the coupling strength of the excitons/vibrations of organic materials, This reduces the chance of heat dissipation.

By cooperating with Professor Ji Yun of Tsinghua University, Professor Hong Wenyi of Ocean University, and Dr. Zhuang Weizong of the National Synchrotron Radiation Center, Professor Pi-Tai Chou's team used the planarization of ligand molecules of platinum metal complexes and the deuteration of hydrogen atoms in organic compounds (Replacing hydrogen with its isotope deuterium), breaking through the world record of 840 nanometers published by the team in Nature Photoelectricity in 2020, and making outstanding international contributions in the principle and design of molecular light emission.

According to this design and synthesis of the electroluminescent element (OLED), the emission wavelength has reached 1000 nanometers, the internal quantum yield is 21%, and the external quantum yield is 4.2%, both of which are current world records. Professor Pi-Tai Chou said that in the future, he will challenge the unprecedented field of light emission in the three infrared regions (1700-2000 nm) of organic molecules and commercialize existing achievements. He welcomes interested scholars and practitioners to join in this grand event. Paper: Nature Photonics volume 16, pages843–850 (2022)

Near-infrared organic light-emitting diodes with very high external quantum efficiency and radiance

Led by Professor Pi-Tai Chou, NTU-CEMAD developed a new theoretical concept incorporating the self-assembly of molecules in optimum orientation to breakdown the long-standing restriction of molecular emission in the near infrared (NIR) region, dubbed as energy gap law. Accordingly, they developed highly efficient NIR organic light emitting diodes (OLEDs), for which the peak emission wavelength at 740 nm and unprecedented PLQY of 81% are due to the exciton-like emission among the molecular aggregate, greatly suppressing the exciton-optical phonon coupling. The resulted external quantum efficiency of 24 ± 1% and maximum radiance of (3.6 ± 0.2) x 105 mW·sr-1·m‒2 set up the world record that is 10 times higher than those have been reported. This leading concept and technology can be applied to any ingeniously design molecular system to broaden the spectrum of scope. Future perspective for NIR OLEDs is far-reaching, which can potentially be applied in NIR phototherapy, bio-imaging, photodetector, car sensor and plant growth in agriculture. Paper: Nature Photonics. 2016, DOI: 10.1038/NPHOTON.2016.230

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Professor Pi-Tai Chou's research team synthesized a series of donor-acceptor coordinated Pt(II) complexes to unveil the ordered solid-state packing arrangement, as highlighted by the edge-on preferred orientation in the vacuum-evaporated thin films. They are trying to reach the unprecedented ~ 1000 nm emission with high performance OLEDs. This leading concept and technology can be applied to any ingeniously design molecular system to broaden the spectrum of scope. (Source: Ministry of Science and Technology, Department of Natural Sciences and Sustainable Development)

News and Events

  • Professor Pi-Tai Chou obtained the 2015 TWAS Prize, for his distinguished contribution to fundamental photochemistry through electronically excited-state photodynamics of organic and organometallic materials in condensed phases.


The 248th ACS National Meeting and Exposition,San Francisco (August 10-14, 2014)

In this meeting, there were 29 technical divisions and nine committees in original programming over 1,013 half-day oral sessions and 168 poster sessions, including Sci-Mix. More than 7,400 papers were presented, and nearly 4,400 poster presentations took place at the meeting. One of two organizers for the proton transfer seesion is Professor Pi-Tai Chou, and the session is partly supported by YEN-CHING-LIN Industrial Research Center, National Taiwan University and TopGiga Material.

The cartoon on the meeting poster (as shown on the picture) is to indicate that a proton (H+) is moving from Taiwan to USA, ymbolizing the core issue presented in the proton transfer session.

The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 161,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. For details, please refer to 248th ACS National Meeting's final program.

The 7th Aseanian Conference on Dye-sensitized and Organic Solar Cells, Taipei (October 26-29, 2012)

The conference took place at Liberal Education Classroom, National Taiwan University, Taipei, more than 300 papers are expected to be presented in oral and poster sessions covering frontline research of Dye‐sensitized and Organic Solar Cells. In this coming DSC‐ OPV7, many world-renowned scientists Prof. Michael Grätzel, Joseph T. Hupp, James Durrant, Hiroshi Segawa, Juan Bisquert, and Mercouri G. Kanatzidis gave speech in the plenary section.

For details, please refer to DSC-OPV7 Official Website.