Incorporation of Designed Donor−Acceptor−Donor Segments in a Host Polymer for Strong Near-Infrared Emission from a Large-Area Light-Emitting Electrochemical Cell
Journal article, 2018
Cost-efficient thin-film devices that emit in the nearinfrared (NIR) range promise a wide range of important applications. Here, the synthesis and NIR application of a series of copolymers comprising poly[indacenodithieno[3,2-b]thiophene-2,8-diyl] (PIDTT) as the host and different donor−acceptor−donor (DAD) segments as the guest are reported. We find that a key design criterion for efficient solid-state host-to-guest energy transfer is that the DAD conformation is compatible with the conformation of the host. Such host−guest copolymers are evaluated as the emitter in light-emitting electrochemical cells (LECs) and organic light-emitting diodes, and the best performance is invariably attained from the LEC devices because of the observed balanced electrochemical doping that alleviates issues with a noncentered emission zone. An LEC device comprising a host−guest copolymer with 4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene as the donor and benzo[c][1,2,5]thiadiazole as the acceptor delivers an impressive near-infrared (NIR) performance in the form of a high radiance of 1458 μW/cm2 at a peak wavelength of 725 nm when driven by a current density of 500 mA/cm2, a second-fast turn-on, and a good stress stability as manifested in a constant radiance output during 3 days of uninterrupted operation. The high-molecular-weight copolymer features excellent processability, and the potential for low-cost and scalable NIR applications is verified through a spray-coating fabrication of a >40 cm2 large-area device, which emits intense and uniform NIR light at a low drive voltage of 4.5 V.
NIR
large-area device
LEC
solution processing
copolymer
light-emitting electrochemical cell
near-infrared
Author
Petri Henrik Murto
Flinders University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Shi Tang
LunaLEC AB
Umeå University
Christian Larsen
Umeå University
LunaLEC AB
Xiaofeng Xu
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Andreas Sandström
LunaLEC AB
Juuso Pietarinen
University of Oulu
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Benedikt Bagemihl
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Birhan Alkadir Abdulahi
Addis Ababa University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Wendimagegn Mammo
Addis Ababa University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Mats Andersson
Flinders University
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Ergang Wang
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Ludvig Edman
LunaLEC AB
Umeå University
ACS Applied Energy Materials
25740962 (eISSN)
Vol. 1 4 1753-1761Subject Categories (SSIF 2011)
Polymer Chemistry
Materials Chemistry
Organic Chemistry
Condensed Matter Physics
DOI
10.1021/acsaem.8b00283