TY - JOUR
T1 - High Performance NIR OLEDs with Emission Peak Beyond 760 nm and Maximum EQE of 6.39%
AU - Zhang, Hongyang
AU - Chen, Zhao
AU - Zhu, Longzhi
AU - Wu, Yongquan
AU - Xu, Yuqing
AU - Chen, Shuming
AU - Wong, Wai Yeung
N1 - Funding Information:
W.‐Y.W. thanks the National Natural Science Foundation of China (51873176), Hong Kong Research Grants Council (PolyU153058/19P), the CAS‐Croucher Funding Scheme for Joint Laboratories, Hong Kong Polytechnic University (1‐ZE1C), Research Institute for Smart Energy (RISE) and the Endowed Professorship in Energy from Ms Clarea Au (847S) for the financial support. Y.W. is thankful for the financial support from the National Natural Science Foundation of China (21967001) and Double‐Thousand Talents Plan of Jiangxi Province (jxsq2019201090).
Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2022/6/15
Y1 - 2022/6/15
N2 - Advances in achieving high external quantum efficiency (EQE) of near-infrared (NIR) organic light-emitting diodes (OLEDs) are lagging behind that of the visible-light OLEDs, according to the energy gap law. Herein, two structurally simple NIR-phosphorescent Ir(III) complexes, DTCNIr and PTCNIr, with the cyclometalated ligands functionalized by the 1-phenylisoquinoline-4-carbonitrile moiety and thieno/benzo[b]thiophene moiety are handily accessed within three synthetic steps. The introduction of the cyano unit can significantly lower the lowest unoccupied molecular orbitals whereas incorporating the conjugated group can elevate the highest occupied molecular orbitals of the newly designed Ir(III) complexes. The intramolecular charge transfer (ICT) transitions are enhanced due to the increased donor–acceptor interaction inside the metallophosphor. As a result, the emissions are red-shifted to the NIR region with fast radiative decay. A maximum external quantum efficiency (EQE) of 8.11% with the emission peak at 726 nm for DTCNIr and a maximum EQE of 6.39% with the emission peak at 763 nm for PTCNIr are achieved in the NIR OLEDs by using these Ir(III) materials as the dopant emitters, a champion efficiency in the Ir(III)-based OLEDs with the emission peak exceeding 760 nm.
AB - Advances in achieving high external quantum efficiency (EQE) of near-infrared (NIR) organic light-emitting diodes (OLEDs) are lagging behind that of the visible-light OLEDs, according to the energy gap law. Herein, two structurally simple NIR-phosphorescent Ir(III) complexes, DTCNIr and PTCNIr, with the cyclometalated ligands functionalized by the 1-phenylisoquinoline-4-carbonitrile moiety and thieno/benzo[b]thiophene moiety are handily accessed within three synthetic steps. The introduction of the cyano unit can significantly lower the lowest unoccupied molecular orbitals whereas incorporating the conjugated group can elevate the highest occupied molecular orbitals of the newly designed Ir(III) complexes. The intramolecular charge transfer (ICT) transitions are enhanced due to the increased donor–acceptor interaction inside the metallophosphor. As a result, the emissions are red-shifted to the NIR region with fast radiative decay. A maximum external quantum efficiency (EQE) of 8.11% with the emission peak at 726 nm for DTCNIr and a maximum EQE of 6.39% with the emission peak at 763 nm for PTCNIr are achieved in the NIR OLEDs by using these Ir(III) materials as the dopant emitters, a champion efficiency in the Ir(III)-based OLEDs with the emission peak exceeding 760 nm.
KW - high external quantum efficiency
KW - intramolecular charge transfer transition
KW - near-infrared emission
KW - organic light-emitting diodes
UR - http://www.scopus.com/inward/record.url?scp=85131839952&partnerID=8YFLogxK
U2 - 10.1002/adom.202200111
DO - 10.1002/adom.202200111
M3 - Journal article
AN - SCOPUS:85131839952
SN - 2195-1071
JO - Advanced Optical Materials
JF - Advanced Optical Materials
M1 - 2200111
ER -