TY - JOUR
T1 - An Efficient, “Burn in” Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor
AU - Cha, Hyojung
AU - Wu, Jiaying
AU - Wadsworth, Andrew
AU - Nagitta, Jade
AU - Limbu, Saurav
AU - Pont, Sebastian
AU - Li, Zhe
AU - Searle, Justin
AU - Wyatt, Mark F.
AU - Baran, Derya
AU - Kim, Ji-Seon
AU - McCulloch, Iain
AU - Durrant, James R.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): OSR-2015-CRG4-2572
Acknowledgements: The authors gratefully acknowledge funding supported by KAUST under the Grant Agreement number OSR-2015-CRG4-2572, the EU FP7 project CHEETAH, the EPSRC through the Centre for Doctoral Training in Plastic Electronics (EP/L0160702/1) and thank Pabitra Shakya for assistance in device fabrication.
PY - 2017/6/28
Y1 - 2017/6/28
N2 - A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3'″-di(2-octyldodecyl)-2,2';5',2″;5″,2'″-quaterthiophen-5,5'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C71 butyric acid methyl ester (PC71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC71 BM solar cells show significant efficiency loss under simulated solar irradiation (“burn in” degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC71BM devices.
AB - A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3'″-di(2-octyldodecyl)-2,2';5',2″;5″,2'″-quaterthiophen-5,5'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C71 butyric acid methyl ester (PC71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC71 BM solar cells show significant efficiency loss under simulated solar irradiation (“burn in” degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC71BM devices.
UR - http://hdl.handle.net/10754/625643
UR - http://onlinelibrary.wiley.com/doi/10.1002/adma.201701156/full
UR - http://www.scopus.com/inward/record.url?scp=85021421780&partnerID=8YFLogxK
U2 - 10.1002/adma.201701156
DO - 10.1002/adma.201701156
M3 - Article
C2 - 28657152
AN - SCOPUS:85021421780
VL - 29
SP - 1701156
JO - Advanced Materials
JF - Advanced Materials
SN - 0935-9648
IS - 33
ER -