Efficient Color-Tunable Copper(I) Complexes and Their Applications in Solution-Processed Organic Light-Emitting Diodes.
A series of dppnc- and neocuproine-based CuIcomplexes (dppnc=7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate) are synthesized and the emission color of these CuIcomplexes can be tuned from green to deep red via rational modification of the neocuproine ligand structure. The molecular structures of the emissive CuIcomplexes, Cu(dppnc)-G (green emitting), Cu(dppnc)-Y (yellow emitting), and Cu(dppnc)-R (red emitting), are characterized and their electronic structures and related transition properties are elucidated by photo-physical and computational (density functional theory) studies. The calculation results suggest that thermally activated delayed fluorescence (TADF) is the emission mechanism for these CuIcomplexes. Efficient solution-processed green-, yellow-, and red-emitting OLEDs are fabricated based on the emissive complexes as the dopants. High external quantum efficiency (EQE) of 15.20 % and current efficiency of 48.15 cd A-1at 1000 cd m-2are achieved in the green-emitting device with Cu(dppnc)-G. A maximum EQE of 10.17 %, CIE coordinates of (0.61, 0.38) and a maximum electroluminescent peak of 631 nm are achieved in the red device based on Cu(dppnc)-R.
State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
Gary Kwok-Ming
GK
So
State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.|HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518053, P. R. China.
Gang
G
Cheng
International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, P. R. China.
Jian
J
Wang
State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
Xiaoyong
X
Chang
State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
Chi-Chung
CC
Kwok
International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, P. R. China.
Hongxing
H
Zhang
State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.|HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518053, P. R. China.
Chi-Ming
CM
Che
color-tunable; copper complexes; electroluminescence; organic light-emitting diodes; solution process