%0 Journal Article %A Bakulin, Artem A. %A Martyanov, Dmitry S. %A Paraschuk, Dmitry Yu. %A Pshenichnikov, Maxim S. %A H. M. van Loosdrecht, Paul %D 2008 %T Ultrafast Charge Photogeneration Dynamics in Ground-State Charge-Transfer Complexes Based on Conjugated Polymers %U https://acs.figshare.com/articles/journal_contribution/Ultrafast_Charge_Photogeneration_Dynamics_in_Ground_State_Charge_Transfer_Complexes_Based_on_Conjugated_Polymers/2902264 %R 10.1021/jp8048839.s001 %2 https://acs.figshare.com/ndownloader/files/4600408 %K photocurrent measurements %K charge transfer %K CTC band %K geminate recombination %K recombination efficiency %K moment orientation %K electron transfer %K ultrafast experiments %K acceptor %K Conjugated PolymersThe charge photogeneration %K CTCs polaron band %K excitation photon %K Ultrafast Charge Photogeneration Dynamics %K polymer conjugation segment %K polymer chain %K blend %X The charge photogeneration and early recombination in MEH-PPV-based charge-transfer complexes (CTCs) and in MEH-PPV/PCBM blend as a reference are studied by ultrafast visible-pump−IR-probe spectroscopy. After excitation of the CTC band, an immediate (<100 fs) electron transfer is observed from the polymer chain to the acceptor with the same yield as in the MEH-PPV/PCBM blend. The forward charge transfer in the CTCs is followed by an efficient (∼95%) and fast (<30 ps) geminate recombination. For comparison, the recombination efficiency obtained in the MEH-PPV/PCBM blend does not exceed a mere 50%. Polarization-sensitive experiments demonstrate high (∼0.3) values of transient anisotropy for the CTCs polaron band. In contrast, in the MEH-PPV/PCBM blend the dipole moment orientation of the charge-induced transition is less correlated with the polarization of the excitation photon. According to these data, photogeneration and recombination of charges in the CTCs take place locally (i.e., within a single pair of a polymer conjugation segment and an acceptor) while in the MEH-PPV/PCBM blend exciton migration precedes the separation of charges. Results of the ultrafast experiments are supported by photocurrent measurements on the corresponding MEH-PPV/acceptor photodiodes. %I ACS Publications