Singlet Oxygen Generation Employing Conjugated Polymer Photosensitizers Containing Arsenic or Germanium

ABSTRACT Singlet oxygen ( 1 O 2 ), a reactive oxygen species, is generated by exciting triplet oxygen ( 3 O 2 , ground state) via energy transfer from a photosensitizer in its triplet excited state. In this study, heteroatom‐fused conjugated polymers were utilized as photosensitizers for 1 O 2 generation, leveraging their broad and strong absorbance spectra in addition to the heavy atom effect. Monomers of dithienoarsole and dithienogermole were synthesized and copolymerized via Pd‐catalyzed coupling reactions. In contrast, a dithienostibole monomer was unstable under the polymerization condition, undergoing decomposition. The 1 O 2 generation efficacies of the dithienoarsole and dithienogermole polymers were evaluated. This study demonstrated that both the rate and quantum yield of 1 O 2 production were significantly influenced by the selection of fused heteroatom and comonomer.