Observation of a Charge Transfer State in Low-Bandgap Polymer/Fullerene Blend Systems by Photoluminescence and Electroluminescence Studies
Journal article, 2009

The presence of charge transfer states generated by the interaction between the fullerene acceptor PCBM and two alternating copolymers of fluorene with donor-acceptor-donor comonomers are reported; the generation leads to modifications in the polymer bandgap and electronic structure. In one of polymer/fullerene blends, the driving force for photocurrent generation, i.e., the gap between the lowest unoccupied molecular orbitals of the donor and acceptor, is only 0.1 eV, but photocurrent is generated. It is shown that the presence of a charge transfer state is more important than the driving force. The charge transfer states are visible through new emission peaks in the photoluminescence spectra and through electroluminescence at a forward bias. The photoluminescence can be quenched under reverse bias, and can be directly correlated to the mechanism of photocurrent generation. The excited charge transfer state is easily dissociated into free charge carriers, and is an important intermediate state through which free charge carriers are generated.

Author

Y. Zhou

Linköping University

Kristofer Tvingstedt

Linköping University

Fengling Zhang

Linköping University

Chunxia Du

Linköping University

Wei-Xin Ni

Linköping University

Mats Andersson

Chalmers, Chemical and Biological Engineering, Polymer Technology

Olle Inganäs

Linköping University

Advanced Materials for Optics and Electronics

1616301x (ISSN) 1616-3028 (eISSN)

Vol. 19 20 3293-3299

Subject Categories

Polymer Chemistry

DOI

10.1002/adfm.200900702

More information

Latest update

2/28/2018