A Comparison of Charge Separation Dynamics in Organic Blend Films Employing Fullerene and Perylene Diimide Electron Acceptors.
We report a comparison of charge carrier dynamics and device performance for low band gap polymer PBDTTT-CT in blends with the fullerene acceptor PC71BM and a PDI derivative with similar electron affinities. Charge separation and recombination dynamics are found to be remarkably similar for these two acceptors, with both blends exhibiting efficient, ultrafast charge separation (time constants of 1.6 and 1.4 ps, respectively). The lower device performance for the PDI acceptor (1.75% compared to 3.5% for the equivalent PC71BM device) is shown to result from slower charge transport, increasing nongeminate recombination losses during charge collection.
†Centre for Plastic Electronics, Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Safa
S
Shoaee
†Centre for Plastic Electronics, Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Florent
F
Deledalle
†Centre for Plastic Electronics, Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Pabitra
P
Shakya Tuladhar
‡Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
Ravichandran
R
Shivanna
§International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
Sridhar
S
Rajaram
‡Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
K S
KS
Narayan
†Centre for Plastic Electronics, Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
James R
JR
Durrant
charge photogeneration; morphology; nongeminate recombination