TY - JOUR
T1 - C1-Symmetric [Ir(C^N1)(C^N2)(O^O)]-Tris-Heteroleptic Iridium(III)-Complexes with the Preferentially Horizontal Orientation for High-Performance Near-Infrared Organic Light-Emitting Diodes
AU - Li, Wentao
AU - Wang, Baowen
AU - Miao, Tiezheng
AU - Liu, Jiaxiang
AU - Lü, Xingqiang
AU - Fu, Guorui
AU - Shi, Linxi
AU - Chen, Zhongning
AU - Qian, Pengcheng
AU - Wong, Wai Yeung
N1 - Funding Information:
W.L. and B.W. contributed equally and should be considered co-first authors. X. L? thanks the National Natural Science Foundation (21373160 and 21173165) and the State Key Laboratory of Structure Chemistry (20190026) in China. Z.C. thanks the National Natural Science Foundation (21801242 and 21701171) in China. W.-Y.W. thanks the Hong Kong Research Grants Council (PolyU153058/19P), Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials (2019B121205002), the Hong Kong Polytechnic University (1-ZE1C and YW4T), Research Institute for Smart Energy (RISE) and the Endowed Professorship in Energy from Ms. Clarea Au (847S). Dr. P.Q. thanks the Foundation of Wenzhou Science & Technology Bureau (W20170003) and the National Natural Science Foundation of China (21828102).
Funding Information:
W.L. and B.W. contributed equally and should be considered co‐first authors. X. Lü thanks the National Natural Science Foundation (21373160 and 21173165) and the State Key Laboratory of Structure Chemistry (20190026) in China. Z.C. thanks the National Natural Science Foundation (21801242 and 21701171) in China. W.‐Y.W. thanks the Hong Kong Research Grants Council (PolyU153058/19P), Guangdong‐Hong Kong‐Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials (2019B121205002), the Hong Kong Polytechnic University (1‐ZE1C and YW4T), Research Institute for Smart Energy (RISE) and the Endowed Professorship in Energy from Ms. Clarea Au (847S). Dr. P.Q. thanks the Foundation of Wenzhou Science & Technology Bureau (W20170003) and the National Natural Science Foundation of China (21828102).
Publisher Copyright:
© 2021 Wiley-VCH GmbH.
PY - 2021/8/4
Y1 - 2021/8/4
N2 - The development of high-efficiency near-infrared (NIR)-emitting Ir(III)-complex-based phosphors for reliable NIR-OLEDs (near-infrared organic light-emitting diodes) is still a formidable challenge. Herein, a molecule-engineered approach is developed to afford three C1-symmetric [Ir(C^N1)(C^N2)(O^O)]-tris-heteroleptic Ir(III)-complexes ([Ir(iqbt)(dFppy)(acac)] (1), [Ir(iqbt)(ppy)(acac)] (2), and [Ir(iqbt)(dpqx)(acac)] (3)), whose good NIR-luminescent efficiency (ΦPL = 0.18 for 1 (λem = 703 nm), 0.26 for 2 (λem = 715 nm) or 0.28 for 3 (λem = 707 nm)) originates from the strengthened 3MLCT contribution (MLCT = metal-to-ligand charge transfer). Moreover, the quantitative molecular orientation determination of their doped emitting layers (EMLs) reveals that the preferentially horizontal orientation of the emitting dipoles is beneficial to their highly efficient NIR-OLEDs with light out-coupling. Especially for the NIR-OLED -2 with λem = 715 nm, a high performance (ηEQEMax = 5.30% and negligible (<2%) efficiency-roll-off) is realized among the reported solution-processed NIR-OLEDs based on Ir(III)-complexes at similar color gamut. This result shows that C1-symmetric [Ir(C^N1)(C^N2)(O^O)]-tris-heteroleptic Ir(III)-complexes can provide a new platform to low-cost and large-area scalable NIR-OLEDs.
AB - The development of high-efficiency near-infrared (NIR)-emitting Ir(III)-complex-based phosphors for reliable NIR-OLEDs (near-infrared organic light-emitting diodes) is still a formidable challenge. Herein, a molecule-engineered approach is developed to afford three C1-symmetric [Ir(C^N1)(C^N2)(O^O)]-tris-heteroleptic Ir(III)-complexes ([Ir(iqbt)(dFppy)(acac)] (1), [Ir(iqbt)(ppy)(acac)] (2), and [Ir(iqbt)(dpqx)(acac)] (3)), whose good NIR-luminescent efficiency (ΦPL = 0.18 for 1 (λem = 703 nm), 0.26 for 2 (λem = 715 nm) or 0.28 for 3 (λem = 707 nm)) originates from the strengthened 3MLCT contribution (MLCT = metal-to-ligand charge transfer). Moreover, the quantitative molecular orientation determination of their doped emitting layers (EMLs) reveals that the preferentially horizontal orientation of the emitting dipoles is beneficial to their highly efficient NIR-OLEDs with light out-coupling. Especially for the NIR-OLED -2 with λem = 715 nm, a high performance (ηEQEMax = 5.30% and negligible (<2%) efficiency-roll-off) is realized among the reported solution-processed NIR-OLEDs based on Ir(III)-complexes at similar color gamut. This result shows that C1-symmetric [Ir(C^N1)(C^N2)(O^O)]-tris-heteroleptic Ir(III)-complexes can provide a new platform to low-cost and large-area scalable NIR-OLEDs.
KW - cyclometalated Ir(III)-complex
KW - near-infrared phosphorescence
KW - organic light-emitting diodes
KW - solution-processed devices
KW - transition dipole moment
KW - tris-heteroleptic configuration
UR - http://www.scopus.com/inward/record.url?scp=85105217386&partnerID=8YFLogxK
U2 - 10.1002/adom.202100117
DO - 10.1002/adom.202100117
M3 - Journal article
AN - SCOPUS:85105217386
SN - 2195-1071
VL - 9
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 15
M1 - 2100117
ER -