Prof. Iain McCULLOCH of Princeton highlights next-generation solar fuels at PAIR Seminar

Green hydrogen, produced from water using renewable energy, is anticipated to become a leading fuel of the future, offering clean, carbon-free energy for a wide range of industrial applications.  It also has the potential to provide complementary energy storage when combined with intermittent solar power.  However, achieving economically competitive, large-scale solar-generated hydrogen production remains a significant challenge. Photochemical water splitting, a process that uses light-absorbing nanoparticle semiconductors to drive redox reactions on their surface, offers a promising solution.

At the PAIR Seminar on 2 October 2025, Prof. Iain McCULLOCH of Princeton University, USA, shared the latest developments in photochemical water splitting.  His talk, titled “Harnessing the Sun for Chemistry”, focused on the use of light-absorbing nanoparticle semiconductors capable of driving redox reactions on their surface.  The seminar attracted over 80 in-person participants and an online audience of more than 15,500 across various social media platforms. 

To begin his presentation, Prof. McCulloch briefly introduced the development of photo-catalysts fabricated from organic semiconductors, which can be chemically tuned to absorb strongly throughout the UV-visible spectrum.  His research has demonstrated that these organic semiconductor nanoparticles, featuring an internal donor/acceptor heterojunction between two organic semiconductors with a type II energy level offset, achieve higher solar-to-hydrogen efficiency than traditional inorganic photocatalysts.  The donor/acceptor heterojunction significantly enhances charge generation within the nanoparticles, thereby greatly improving their hydrogen production efficiency.  Furthermore, his team has also shown that adjusting the nanoparticle composition can substantially increase hydrogen production efficiency.

Prof. McCulloch’s research team also observed that the high efficiency of these nanoparticles stems from their ability to generate exceptionally long-lived reactive charges upon illumination, increasing their likelihood of participation in photocatalytic reactions.  In addition, he discussed solution-processable, linear conjugated polymers of intrinsic porosity for gas-phase carbon dioxide photoreduction, highlighting the potential of such polymers in transforming carbon dioxide into solar fuels.

Following the presentation was a lively question-and-answer session moderated by Prof. YAN Feng, Associate Director of Research Institute for Intelligent Wearable Systems (RI-IWEAR) and Chair Professor of Organic Electronics.  The audience engaged in a productive discussion with Prof. McCulloch.