TY - JOUR
T1 - Ionic Density Control of Conjugated Polyelectrolytes via Postpolymerization Modification to Enhance Hole-Blocking Property for Highly Efficient PLEDs with Fast Response Times
AU - Yan, Hao
AU - Cong, Shengyu
AU - Daboczi, Matyas
AU - Limbu, Saurav
AU - Hamilton, Iain
AU - Kwon, Sooncheol
AU - Rapley, Charlotte L.
AU - Tahir, Syuhada Mohd
AU - Kerherve, Gwilherm
AU - Payne, David
AU - Heeney, Martin
AU - Kim, Ji Seon
N1 - Publisher Copyright:
© 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH.
PY - 2023/12/4
Y1 - 2023/12/4
N2 - For an ideal electron interlayer, both electron injection and hole-blocking properties are important to achieve better polymer light-emitting devices (PLEDs) performance. Conjugated polyelectrolytes (CPEs) are applied widely in PLEDs to enhance charge injection. Understanding the role of backbone structures and energetic matching between the CPEs and emitters can benefit charge injection and balance. Herein, a postpolymerization approach to introduce varying amounts of alkyl sulfonate groups onto the backbone of a copolymer of 5-fluoro-2,1,3-benzothiadiazole and 9,9′-dioctylfluorene is utilized. This study finds that device performance is dependent on the percentage of sulfonate groups incorporated, with the optimal copolymer (CPE-50%) maintaining efficient ohmic electron injection and gaining enhanced hole-blocking properties, thereby achieving the most balanced hole/electron current. Therefore, the PLED with CPE-50% interlayer exhibits the highest efficiency (20.3 cd A−1, 20.2 lm W−1) and the fastest response time (4.3 µs), which is the highest efficiency among conventional thin (70 nm) F8BT PLEDs with CPEs. These results highlight the importance of balanced charge carrier density in CPEs and highlight that postpolymerization modification is a useful method for fine-tuning ionic content.
AB - For an ideal electron interlayer, both electron injection and hole-blocking properties are important to achieve better polymer light-emitting devices (PLEDs) performance. Conjugated polyelectrolytes (CPEs) are applied widely in PLEDs to enhance charge injection. Understanding the role of backbone structures and energetic matching between the CPEs and emitters can benefit charge injection and balance. Herein, a postpolymerization approach to introduce varying amounts of alkyl sulfonate groups onto the backbone of a copolymer of 5-fluoro-2,1,3-benzothiadiazole and 9,9′-dioctylfluorene is utilized. This study finds that device performance is dependent on the percentage of sulfonate groups incorporated, with the optimal copolymer (CPE-50%) maintaining efficient ohmic electron injection and gaining enhanced hole-blocking properties, thereby achieving the most balanced hole/electron current. Therefore, the PLED with CPE-50% interlayer exhibits the highest efficiency (20.3 cd A−1, 20.2 lm W−1) and the fastest response time (4.3 µs), which is the highest efficiency among conventional thin (70 nm) F8BT PLEDs with CPEs. These results highlight the importance of balanced charge carrier density in CPEs and highlight that postpolymerization modification is a useful method for fine-tuning ionic content.
KW - conjugated polyelectrolytes
KW - hole blocking
KW - ionic density
KW - PLEDs
KW - post-polymerization modification
UR - http://www.scopus.com/inward/record.url?scp=85165304289&partnerID=8YFLogxK
U2 - 10.1002/adom.202300988
DO - 10.1002/adom.202300988
M3 - Article
AN - SCOPUS:85165304289
SN - 2195-1071
VL - 11
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 23
M1 - 2300988
ER -