TY - JOUR
T1 - Combining Benzotriazole and Benzodithiophene Host Units in Host–Guest Polymers for Efficient and Stable Near‐Infrared Emission from Light‐Emitting Electrochemical Cells
AU - Xiong, Wenjing
AU - Zhu, Weiguo
AU - Murto, Petri
AU - Edman, Ludvig
AU - Wang, Ergang
PY - 2019/8/5
Y1 - 2019/8/5
N2 - A set of host–guest copolymers with alternating benzodithiophene and benzotriazole (BTz) derivatives as host units and 4,7-bis(5-bromothiophen-2-yl)-benzo[c][1,2,5]thiadiazole as the minority guest are synthesized, characterized, and evaluated for applications. A light-emitting electrochemical cell (LEC) comprising such a host–guest copolymer delivers fast-response near-infrared (NIR) emission peaked at 723 nm with a high radiance of 169 µW cm−2 at a low drive voltage of 3.6 V. The NIR-LEC also features good stability, as the peak NIR output only drops by 8% after 350 h of continuous operation. It is, however, found that the LEC performance is highly sensitive to the detailed chemical structure of the host backbone, and that the addition of electron-donating thiophene bridging units onto the BTz unit is highly positive while the inclusion of fluorine atoms results in a drastically lowered performance, presumably because of the emergence of hydrogen bonding within the active material.
AB - A set of host–guest copolymers with alternating benzodithiophene and benzotriazole (BTz) derivatives as host units and 4,7-bis(5-bromothiophen-2-yl)-benzo[c][1,2,5]thiadiazole as the minority guest are synthesized, characterized, and evaluated for applications. A light-emitting electrochemical cell (LEC) comprising such a host–guest copolymer delivers fast-response near-infrared (NIR) emission peaked at 723 nm with a high radiance of 169 µW cm−2 at a low drive voltage of 3.6 V. The NIR-LEC also features good stability, as the peak NIR output only drops by 8% after 350 h of continuous operation. It is, however, found that the LEC performance is highly sensitive to the detailed chemical structure of the host backbone, and that the addition of electron-donating thiophene bridging units onto the BTz unit is highly positive while the inclusion of fluorine atoms results in a drastically lowered performance, presumably because of the emergence of hydrogen bonding within the active material.
UR - http://dx.doi.org/10.1002/adom.201900280
U2 - 10.1002/adom.201900280
DO - 10.1002/adom.201900280
M3 - Article
SN - 2195-1071
VL - 7
JO - ADVANCED OPTICAL MATERIALS
JF - ADVANCED OPTICAL MATERIALS
IS - 15
M1 - 1900280
ER -