TY  - JOUR
A1  - Vandewal, Koen
A1  - Albrecht, Steve
A1  - Hoke, Eric T.
A1  - Graham, Kenneth R.
A1  - Widmer, Johannes
A1  - Douglas, Jessica D.
A1  - Schubert, Marcel
A1  - Mateker, William R.
A1  - Bloking, Jason T.
A1  - Burkhard, George F.
A1  - Sellinger, Alan
A1  - Frechet, Jean M. J.
A1  - Amassian, Aram
A1  - Riede, Moritz K.
A1  - McGehee, Michael D.
A1  - Neher, Dieter
A1  - Salleo, Alberto
T1  - Efficient charge generation by relaxed charge-transfer states at organic interfaces
JF  - Nature materials
N2  - carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold viaweakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer: fullerene, small-molecule:C-60 and polymer: polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.
Y1  - 2014
U6  - https://doi.org/10.1038/NMAT3807
SN  - 1476-1122
SN  - 1476-4660
VL  - 13
IS  - 1
SP  - 63
EP  - 68
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Albrecht, Steve
A1  - Vandewal, Koen
A1  - Tumbleston, John R.
A1  - Fischer, Florian S. U.
A1  - Douglas, Jessica D.
A1  - Frechet, Jean M. J.
A1  - Ludwigs, Sabine
A1  - Ade, Harald W.
A1  - Salleo, Alberto
A1  - Neher, Dieter
T1  - On the efficiency of charge transfer state splitting in polymer: Fullerene solar cells
JF  - Advanced materials
KW  - organic solar cells
KW  - charge generation
KW  - geminate recombination
KW  - charge transfer states
KW  - driving force
KW  - excess energy
KW  - morphology
KW  - spectroelectrochemistry
Y1  - 2014
U6  - https://doi.org/10.1002/adma.201305283
SN  - 0935-9648
SN  - 1521-4095
VL  - 26
IS  - 16
SP  - 2533
EP  - 2539
PB  - Wiley-VCH
CY  - Weinheim
ER  -