TY - JOUR
T1 - The Role of Balancing Carrier Transport in Realizing an Efficient Orange-Red Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diode
AU - Tan, Ji-Hua
AU - Jin, Jia-Ming
AU - Chen, Wen-Cheng
AU - Cao, Chen
AU - Wang, Ruifang
AU - Zhu, Ze-Lin
AU - Huo, Yanping
AU - Lee, Chun-Sing
PY - 2022/11/30
Y1 - 2022/11/30
N2 - Simultaneously realizing improved carrier mobility and good photoluminescence (PL) efficiency in red thermally activated delayed-fluorescence (TADF) emitters remains challenging but important. Herein, two isomeric orange-red TADF emitters, oPDM and pPDM, with the same basic donor-acceptor backbone but a pyrimidine (Pm) attachment at different positions are designed and synthesized. The two emitters show similarly good PL properties, including narrow singlet-triplet energy offsets (0.11 and 0.15 eV) and high photoluminescence quantum yields (ca. 100 and 88%) in doped films. An orange-red organic light-emitting diode (OLED) employing oPDM as an emitter achieves an almost twice as high maximum external quantum efficiency (28.2%) compared with that of a pPDM-based OLED. More balanced carrier-transporting properties are responsible for their contrasting device performances, and the position effect of the Pm substituent leads to significantly distinct molecular packing behaviors in the aggregate states and different carrier mobilities.
AB - Simultaneously realizing improved carrier mobility and good photoluminescence (PL) efficiency in red thermally activated delayed-fluorescence (TADF) emitters remains challenging but important. Herein, two isomeric orange-red TADF emitters, oPDM and pPDM, with the same basic donor-acceptor backbone but a pyrimidine (Pm) attachment at different positions are designed and synthesized. The two emitters show similarly good PL properties, including narrow singlet-triplet energy offsets (0.11 and 0.15 eV) and high photoluminescence quantum yields (ca. 100 and 88%) in doped films. An orange-red organic light-emitting diode (OLED) employing oPDM as an emitter achieves an almost twice as high maximum external quantum efficiency (28.2%) compared with that of a pPDM-based OLED. More balanced carrier-transporting properties are responsible for their contrasting device performances, and the position effect of the Pm substituent leads to significantly distinct molecular packing behaviors in the aggregate states and different carrier mobilities.
KW - carrier balance
KW - carrier mobility
KW - orange-red emission
KW - organic light-emitting diodes
KW - thermally activated delayed fluorescence
UR - http://www.scopus.com/inward/record.url?scp=85142142686&partnerID=8YFLogxK
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-85142142686&origin=recordpage
U2 - 10.1021/acsami.2c17492
DO - 10.1021/acsami.2c17492
M3 - RGC 21 - Publication in refereed journal
C2 - 36379027
SN - 1944-8244
VL - 14
SP - 53120
EP - 53128
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 47
ER -