The Precision Photochemistry Paradigm
Event details
| Date | 05.11.2026 |
| Hour | 11:00 › 12:00 |
| Speaker | Prof. Christopher Barner-Kowollik, Karlsruhe Institute of Technology Germany, and Queensland University of Technology Australia |
| Location | |
| Category | Conferences - Seminars |
| Event Language | English |
This is a special joint seminar organized by IEM and ISIC, as part of a two-part lecture series. The first lecture will take place on November 4.
Photochemical action plots map reactivity wavelength-by-wavelength and consistently reveal a mismatch between absorptivity and product yield, challenging the paradigm that maximum yield is dictated by maximum absorption. Standard constant concentration action plots capture the real, practically relevant outcome: The sum of every effect from wavelength-dependent excited-state dynamics (intersystem crossing, non-radiative decay, lifetimes, conical intersections and the resulting quantum yield) to attenuation-driven effects coupled to non-linear kinetics, photobleaching, oxygen quenching and possibly scattering. Herein, we introduce two new experimental action plots termed SAME (Same Absorbance, Molarity and Extinction coefficient) and EQUIVALENT (Equivalent Photon Flux Density Under Invariant Absorbance via Length, Energy and Time) that isolate excited-state and photophysical quantum yields from all other effects. Applied to two important photoinitiators during methyl methacrylate (MMA) photopolymerization, both demonstrate that conversion and initiator decay remains strongly wavelength-dependent, confirming that the precise prediction of wavelength-dependent photochemical outcomes requires treating absorptivity, excited-state dynamics and other effects as independent, wavelength-resolved variables.
Biography
Christopher Barner-Kowollik is a leading expert in photochemistry, exploiting precision photochemical concepts for advanced soft matter material synthesis, including for light-driven 3D printing. He and his team developed a wide array of multi-colour photochemical reactions modes and pioneered wavelength-resolved photochemical action plots, which have demonstrated wavelength-dependent reactivity that is often mismatched with molecular absorptivity. He currently leads research teams at the Karlsruhe Institute of Technology (KIT) and the Queensland University of Technology (QUT). After a PhD in Göttingen, he held leadership roles in Australia and Germany, including at UNSW and KIT, before establishing QUT’s Soft Matter Materials Laboratory. In 2026, he was appointed Institute Director and Alexander von Humboldt Professor at the KIT. His work has earned numerous international awards, including the UK Macro Medal (2020), the European Polymer Federation Prize (2022), the Royal Society of Chemistry Centenary Prize (2023), and Germany’s Alexander von Humboldt Professorship (2025).
Photochemical action plots map reactivity wavelength-by-wavelength and consistently reveal a mismatch between absorptivity and product yield, challenging the paradigm that maximum yield is dictated by maximum absorption. Standard constant concentration action plots capture the real, practically relevant outcome: The sum of every effect from wavelength-dependent excited-state dynamics (intersystem crossing, non-radiative decay, lifetimes, conical intersections and the resulting quantum yield) to attenuation-driven effects coupled to non-linear kinetics, photobleaching, oxygen quenching and possibly scattering. Herein, we introduce two new experimental action plots termed SAME (Same Absorbance, Molarity and Extinction coefficient) and EQUIVALENT (Equivalent Photon Flux Density Under Invariant Absorbance via Length, Energy and Time) that isolate excited-state and photophysical quantum yields from all other effects. Applied to two important photoinitiators during methyl methacrylate (MMA) photopolymerization, both demonstrate that conversion and initiator decay remains strongly wavelength-dependent, confirming that the precise prediction of wavelength-dependent photochemical outcomes requires treating absorptivity, excited-state dynamics and other effects as independent, wavelength-resolved variables.
Biography
Christopher Barner-Kowollik is a leading expert in photochemistry, exploiting precision photochemical concepts for advanced soft matter material synthesis, including for light-driven 3D printing. He and his team developed a wide array of multi-colour photochemical reactions modes and pioneered wavelength-resolved photochemical action plots, which have demonstrated wavelength-dependent reactivity that is often mismatched with molecular absorptivity. He currently leads research teams at the Karlsruhe Institute of Technology (KIT) and the Queensland University of Technology (QUT). After a PhD in Göttingen, he held leadership roles in Australia and Germany, including at UNSW and KIT, before establishing QUT’s Soft Matter Materials Laboratory. In 2026, he was appointed Institute Director and Alexander von Humboldt Professor at the KIT. His work has earned numerous international awards, including the UK Macro Medal (2020), the European Polymer Federation Prize (2022), the Royal Society of Chemistry Centenary Prize (2023), and Germany’s Alexander von Humboldt Professorship (2025).
Practical information
- General public
- Free
Organizer
- Institute of Electrical and Micro Engineering (IEM), Institute of Chemical Sciences and Engineering (ISIC)
Contact
- Prof. Daryl Yee, Prof. Yujia Zhang, Prof. Suong Nguyen