Correlating triplet yield, singlet oxygen generation and photochemical stability in polymer/fullerene blend films.

The photostability of two donor polymers, DPP-TT-T and PTB7, is compared in neat films and blend films with PC(71)BM. In both neat and blend films, PTB7 is shown to be relatively unstable. This observation is shown to correlate with transient optical studies of long lived polymer triplets and with molecular probe studies of singlet oxygen yields.