TY - JOUR
T1 - Highly efficient polyacetylene–based polyelectrolytes as cathode interfacial layers for organic solar cell applications
AU - Aryal, Um Kanta
AU - Chakravarthi, Nallan
AU - Park, Ho Yeol
AU - Bae, Hyeonjeong
AU - Jin, Sung Ho
AU - Gal, Yeong Soon
PY - 2018/2
Y1 - 2018/2
N2 - For application to inverted organic solar cells (IOSCs), three polyacetylene-based polyelectrolytes, poly(N-alkyl/aryl-2-ethynylpyridinium bromide) (P1-P3), were incorporated as cathode interfacial layers (CILs) between the ZnO and one of the following two photoactive layers: poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) or poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th):PC71BM. This interfacial modification of the IOSCs by the CIL insertion enhanced their performance with an increase in power conversion efficiency (PCE) from 7.46% for a ZnO-based control device to 8.29% for PTB7 and to 9.37% for PTB7-Th. Characterizations of the IOSC devices by using electrical impedance spectroscopy (EIS), space-charge-limited current (SCLC) electron mobility, dark current density-voltage (J-V) curves, and film surface morphology study revealed that the CIL incorporation suppressed the charge recombination and thus facilitated charge extraction, as evidenced by the observed improvement of open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF). The devices with CILs showed higher electron mobility, in line with the higher FF and reduced series resistance. These CILs with ZnO exhibited significantly enhanced PCE and also served as an internal shield against oxygen contamination and humidity, which further increased the device stability.
AB - For application to inverted organic solar cells (IOSCs), three polyacetylene-based polyelectrolytes, poly(N-alkyl/aryl-2-ethynylpyridinium bromide) (P1-P3), were incorporated as cathode interfacial layers (CILs) between the ZnO and one of the following two photoactive layers: poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) or poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th):PC71BM. This interfacial modification of the IOSCs by the CIL insertion enhanced their performance with an increase in power conversion efficiency (PCE) from 7.46% for a ZnO-based control device to 8.29% for PTB7 and to 9.37% for PTB7-Th. Characterizations of the IOSC devices by using electrical impedance spectroscopy (EIS), space-charge-limited current (SCLC) electron mobility, dark current density-voltage (J-V) curves, and film surface morphology study revealed that the CIL incorporation suppressed the charge recombination and thus facilitated charge extraction, as evidenced by the observed improvement of open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF). The devices with CILs showed higher electron mobility, in line with the higher FF and reduced series resistance. These CILs with ZnO exhibited significantly enhanced PCE and also served as an internal shield against oxygen contamination and humidity, which further increased the device stability.
KW - Built-in potential
KW - Cathode interfacial layers
KW - Inverted organic solar cells
KW - Polyacetylene-based polyelectrolytes
U2 - 10.1016/j.orgel.2017.12.006
DO - 10.1016/j.orgel.2017.12.006
M3 - Journal article
AN - SCOPUS:85037523996
SN - 1566-1199
VL - 53
SP - 265
EP - 272
JO - Organic Electronics
JF - Organic Electronics
ER -