Effect of strong coupling on photodegradation of the semiconducting polymer P3HT

Photonic structures are commonly designed to manipulate scattered or emitted light. However, in recent years, they were demonstrated to affect a variety of phenomena, including chemical reactions, which lie outside the traditional electrodynamics domain. In this work, we have studied the effect of a Fabry-Perot cavity on the chemical reaction of practical importance-photodegradation of the semiconducting polymer 2,5-poly(3-hexylthiophene) (P3HT), which is the material of choice in organic photovoltaics. Experimentally, Fabry-Perot cavities, composed of two silver mirrors and filled with P3HT polymer, were photoexposed over tens of hours, and the concentration of the remaining thiophene rings (composing P3HT) was studied as a function of time. It has been found that in the regime of strong coupling with the cavity, characterized by one of the largest values of the Rabi splitting reported in the literature (1.0 eV), the normalized rate of photodegradation is reduced threefold, substantially larger than in the weak coupling regime reported in our recent study. This result adds to the toolbox of strong coupling phenomena and paves the road towards long-range control of chemical reactions and catalysis. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement