TY - JOUR
T1 - Synthesis and characterization of fluorene-based copolymers as electron-transporting materials for PLEDs
AU - Ahn, Ho Ik
AU - Moon, Jong Sik
AU - Kim, Won Geun
AU - Uddin, Mohammad Afsar
AU - Choi, Jongwan
AU - Kim, Chuntae
AU - Woo, Han Young
AU - Kim, Nakjoong
AU - Oh, Jin Woo
N1 - Funding Information:
This research was supported by the Pioneer Research Center Program (NRF-2013M3C1A3065469) through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning .
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/7/3
Y1 - 2015/7/3
N2 - Abstract Owing to their low cost, easy processing, and the possibility of flexible fabrication, polymer light-emitting diodes (PLEDs) are emerging as an important class of materials. Despite promising characteristics, the relatively easy ionization of the well-known low-work-function cathodes such as Ca and Ba prevents the full usage of these materials. Herein, we report the syntheses of three alcohol-soluble conjugated polymers with different conjugation lengths and electron affinities as electron injection and transport materials for PLEDs: poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-tetrafluorobenzene] (PFOH-1), poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-thiophene] (PFOH-2), and poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-benzo-thiadiazole] (PFOH-3). For comparison, devices using Al, Ca, and Al cathodes were also fabricated. The device based on the Al cathode showed lower performance with a luminescence efficiency of 0.93 cd/A and a luminance of 248 cd/m2; that based on the low-work-function metal Ca as the cathode showed a near-threefold increase in luminescence efficiency at 2.51 cd/A and brightness at 856 cd/m2 owing to greatly enhanced electron injection from the cathode; and the device employing the PFOH-3/Al cathode exhibited a luminescence efficiency of 2.35 cd/A and a brightness of 667 cd/m2 at a current density of 35 mA/cm2, which is comparable with the performance of the device with the Ca cathode.
AB - Abstract Owing to their low cost, easy processing, and the possibility of flexible fabrication, polymer light-emitting diodes (PLEDs) are emerging as an important class of materials. Despite promising characteristics, the relatively easy ionization of the well-known low-work-function cathodes such as Ca and Ba prevents the full usage of these materials. Herein, we report the syntheses of three alcohol-soluble conjugated polymers with different conjugation lengths and electron affinities as electron injection and transport materials for PLEDs: poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-tetrafluorobenzene] (PFOH-1), poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-thiophene] (PFOH-2), and poly[9,9-bis(2-dihexylaminoethoxy)fluorene-co-benzo-thiadiazole] (PFOH-3). For comparison, devices using Al, Ca, and Al cathodes were also fabricated. The device based on the Al cathode showed lower performance with a luminescence efficiency of 0.93 cd/A and a luminance of 248 cd/m2; that based on the low-work-function metal Ca as the cathode showed a near-threefold increase in luminescence efficiency at 2.51 cd/A and brightness at 856 cd/m2 owing to greatly enhanced electron injection from the cathode; and the device employing the PFOH-3/Al cathode exhibited a luminescence efficiency of 2.35 cd/A and a brightness of 667 cd/m2 at a current density of 35 mA/cm2, which is comparable with the performance of the device with the Ca cathode.
KW - Alcohol-soluble
KW - Electron-transporting materials
KW - Fluorene-based copolymers
KW - PLEDs
UR - http://www.scopus.com/inward/record.url?scp=84934290356&partnerID=8YFLogxK
U2 - 10.1016/j.orgel.2015.06.018
DO - 10.1016/j.orgel.2015.06.018
M3 - Article
AN - SCOPUS:84934290356
VL - 25
SP - 206
EP - 211
JO - Organic Electronics: physics, materials, applications
JF - Organic Electronics: physics, materials, applications
SN - 1566-1199
M1 - 3130
ER -