Influence of Processing Additives on Charge-Transfer Time Scales and Sound Velocity in Organic Bulk Heterojunction Films.
The role of processing additives in organic bulk heterojunction thin films was investigated by means of transient absorption spectroscopy. The rate of ultrafast charge transfer was found to increase when a small amount of diiodooctane was used during film formation. In addition, coherent acoustic phonons were observed, and their velocity was determined. A strong correlation between the sound velocity and the charge-transfer time scale was observed, both of which could be explained by a subtle increase in thin film density.
Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
Loren G
LG
Kaake
Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
Gregory C
GC
Welch
Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
Daniel
D
Moses
Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
Guillermo C
GC
Bazan
Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
Alan J
AJ
Heeger
acoustics; charge dynamics; organic photovoltaic; solvent additives; transient absorption