Slow vibrational relaxation drives ultrafast formation of photoexcited polaron pair states in glycolated conjugated polymers.

ABSTRACT: Glycol sidechains are often used to enhance the performance of organic photoconversion and electrochemical devices. Herein, we study their effects on electronic states and electronic properties. We find that polymer glycolation not only induces more disordered packing, but also results in a higher reorganisation energy due to more localised π-electron density. Transient absorption spectroscopy and femtosecond stimulated Raman spectroscopy are utilised to monitor the structural relaxation dynamics coupled to the excited state formation upon photoexcitation. Singlet excitons are initially formed, followed by polaron pair formation. The associated structural relaxation slows down in glycolated polymers (5 ps vs. 1.25 ps for alkylated), consistent with larger reorganisation energy. This slower

SUBMITTER: Pagano K 

PROVIDER: S-EPMC11263616 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature