TY - JOUR
T1 - Realizing 11.3% efficiency in PffBT4T-2OD fullerene organic solar cells via superior charge extraction at interfaces
AU - Xu, Cheng
AU - Wright, Matthew
AU - Elumalai, Naveen Kumar
AU - Mahmud, Md Arafat
AU - Wang, Dian
AU - Gonçales, Vinicius R
AU - Upama, Mushfika Baishakhi
AU - Haque, Faiazul
AU - Gooding, J Justin
AU - Uddin, Ashraf
PY - 2018
Y1 - 2018
N2 - The influence of interface engineering on the performance and photovoltaic properties of the PffBT4T-2OD 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′′′-diy)] based polymer solar cells (PSCs) are investigated. Owing to the high crystallinity and processing parameter dependent morphology distribution of the PffBT4T-2OD polymer, the performance of the devices can vary significantly with power conversion efficiency (PCE) of around 10% has been reported via such morphology modification. In this work, we demonstrate the effect of trap state passivation at the electron transport layer (ETL)/Polymer interface on the performance of PffBT4T-2OD based PSCs. Aluminium doped ZnO (AZO) and pristine Zinc Oxide (ZnO) are employed as ETLs, which modified the polymer wettability and blend morphology. The interface engineered devices exhibited high PCE of over 11% with high Jsc of about 22.5 mA/cm2 which is about 19% higher than that of the conventional ZnO based devices. The reason behind such distinct enhancements is investigated using several material and device characterization methods including electrochemical impedance spectroscopy (EIS). The recombination resistance (Rrec) of the AZO based device is found to be 4.5 times higher than that of the ZnO devices. The enhanced photovoltaic parameters of the AZO based device are attributed to the superior charge transport characteristics in the ETL as well as at the ETL/polymer interface, enabling effective charge extraction at the respective electrodes with much lesser recombination. The mechanism and the processes behind such enhancements are also elaborated in detail.
AB - The influence of interface engineering on the performance and photovoltaic properties of the PffBT4T-2OD 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′′′-diy)] based polymer solar cells (PSCs) are investigated. Owing to the high crystallinity and processing parameter dependent morphology distribution of the PffBT4T-2OD polymer, the performance of the devices can vary significantly with power conversion efficiency (PCE) of around 10% has been reported via such morphology modification. In this work, we demonstrate the effect of trap state passivation at the electron transport layer (ETL)/Polymer interface on the performance of PffBT4T-2OD based PSCs. Aluminium doped ZnO (AZO) and pristine Zinc Oxide (ZnO) are employed as ETLs, which modified the polymer wettability and blend morphology. The interface engineered devices exhibited high PCE of over 11% with high Jsc of about 22.5 mA/cm2 which is about 19% higher than that of the conventional ZnO based devices. The reason behind such distinct enhancements is investigated using several material and device characterization methods including electrochemical impedance spectroscopy (EIS). The recombination resistance (Rrec) of the AZO based device is found to be 4.5 times higher than that of the ZnO devices. The enhanced photovoltaic parameters of the AZO based device are attributed to the superior charge transport characteristics in the ETL as well as at the ETL/polymer interface, enabling effective charge extraction at the respective electrodes with much lesser recombination. The mechanism and the processes behind such enhancements are also elaborated in detail.
UR - http://www.scopus.com/inward/record.url?scp=85047453986&partnerID=8YFLogxK
U2 - 10.1007/s00339-018-1867-z
DO - 10.1007/s00339-018-1867-z
M3 - Article
VL - 124
SP - 1
EP - 11
JO - Applied Physics A: materials science and processing
JF - Applied Physics A: materials science and processing
SN - 0947-8396
IS - 6
M1 - 449
ER -