@article{Dimitrov:2015:10.1038/ncomms7501,
author = {Dimitrov, SD and Wheeler, S and Niedzialek, D and Schroeder, BC and Utzat, H and Frost, JM and Yao, J and Gillett, A and Tuladhar, PS and McCulloch, I and Nelson, J and Durrant, JR},
doi = {10.1038/ncomms7501},
journal = {Nature Communications},
title = {Polaron pair mediated triplet generation in polymer/fullerene blends},
url = {http://dx.doi.org/10.1038/ncomms7501},
volume = {6},
year = {2015}
}

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TY  - JOUR
AB  - Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields.
AU  - Dimitrov,SD
AU  - Wheeler,S
AU  - Niedzialek,D
AU  - Schroeder,BC
AU  - Utzat,H
AU  - Frost,JM
AU  - Yao,J
AU  - Gillett,A
AU  - Tuladhar,PS
AU  - McCulloch,I
AU  - Nelson,J
AU  - Durrant,JR
DO  - 10.1038/ncomms7501
PY  - 2015///
SN  - 2041-1723
TI  - Polaron pair mediated triplet generation in polymer/fullerene blends
T2  - Nature Communications
UR  - http://dx.doi.org/10.1038/ncomms7501
UR  - http://hdl.handle.net/10044/1/23389
VL  - 6
ER  - 

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