Saturation, Relaxation and Dissociation of Excited Triplet Excitons in Conjugated Polymers

Abstract

Femtosecond pump-probe spectroscopy is used to measure the excited state absorption dynamics in triplet excitons generated by continuous wave excitation of a conjugated polymer. Saturation of the T(1)-T(n) transition is observed, allowing a cross-section of 2.0 x 10(-16) cm(2) to be established. Relaxation to T(1) occurs with a 300 fs timescale, but 20% of T(n) states dissociate into charges.