Conformational Engineering of Two-Coordinate Gold(I) Complexes: Regulation of Excited-State Dynamics for Efficient Delayed Fluorescence

Yang，Jian Gong1,2,3; Song，Xiu Fang4; Cheng，Gang5; Wu，Siping5; Feng，Xingyu1; Cui，Ganglong4; To，Wai Pong5; Chang，Xiaoyong6; Chen，Yong3; Che，Chi Ming5; Yang，Chuluo1; Li，Kai1

2022

10.1021/acsami.2c01776

ACS Applied Materials & Interfaces   影响因子和分区

1944-8244

1944-8252

Carbene-Au-amide (CMA) type complexes, in which the amide and carbene ligands act as an electron donor (D) and acceptor (A), respectively, can exhibit strong delayed fluorescence (DF) from a ligand to ligand charge transfer (LLCT) excited state. Although the coplanar donor-acceptor (D-A) conformation has been suggested to be a crucial factor favoring radiative decay of the charge-transfer excited state, the geometric structural factor underpinning the excited-state mechanism of CMA complexes remains an open question. We herein develop a new class of carbene-Au-carbazolate complexes by introducing large aromatic substituents onto the carbazolate ligand, the presence of which are conceived to restrict the rotation of the Au-N bond and thus confine a twisted D-A conformation in both ground and excited states. A highly twisted D-A orientation is found for the complexes in their crystal structures. Photophysical studies reveal that the twisted conformation induces a decrease in the gap (ΔEST) between the lowest singlet excited state (S1) and the triplet manifold (T1) and thus a faster reverse intersystem crossing (RISC) from T1 to S1 at the expense of oscillator strength for an S1 radiative transition. In comparison with the coplanar analogue, the twisted complexes exhibit comparable or improved DF with quantum yields of up to 94% and short emission lifetimes down to sub-microseconds. The tuning of excited-state dynamics has been well interpreted by density functional theory (DFT) and time-dependent DFT (TDDFT) calculations, which unveil much faster RISC rates for twisted complexes. Solution-processed organic light-emitting diodes (OLEDs) based on the new CMA complexes show promising performances with almost negligible efficiency rolloff at a brightness of 1000 cd m-2. This work implies that neither a coplanar ground-state D-A conformation nor a dynamic rotation of the M-N bond is the key to the realization of efficient DF for CMA complexes.

charge-transfer excited state gold(I) complex metal TADF noncovalent interactions OLED

SCI ; EI

英语

其他

Guangdong Major Project of Basic and Applied Basic Research[2019B030302009] ; National Natural Science Foundation of China[21801170,52130308] ; Guangdong Basic and Applied Basic Research Foundation["2021A1515010175","2021A1515110392"] ; China Postdoctoral Science Foundation[2021M702254] ; Shenzhen Science and Technology Program["KQTD20170330110107046","JCYJ20190808172203553","JCYJ20200109150414471"] ; Department of Science and Technology of Guangdong Province[2019QN01C617]

Science & Technology - Other Topics ; Materials Science

Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000787373300055

AMER CHEMICAL SOC

20221411906729

Amides ; Charge transfer ; Conformations ; Crystal orientation ; Density functional theory ; Excited states ; Fluorescence ; Gold compounds ; Ground state ; Ions ; Organic light emitting diodes (OLED) ; Rotation

Semiconductor Devices and Integrated Circuits:714.2 ; Light/Optics:741.1 ; Physical Chemistry:801.4 ; Chemical Reactions:802.2 ; Organic Compounds:804.1 ; Probability Theory:922.1 ; Mechanics:931.1 ; Atomic and Molecular Physics:931.3 ; Quantum Theory; Quantum Mechanics:931.4 ; Crystal Lattice:933.1.1

2-s2.0-85127346952

Scopus

1.College of Materials Science and Engineering,Shenzhen University,Shenzhen,518055,China
2.College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen,518060,China
3.Key Laboratory of Photochemical Conversion and Optoelectronic Materials,CAS-HKU Joint Laboratory on New Materials,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing,100190,China
4.Key Laboratory of Theoretical and Computational Photochemistry,Ministry of Education,Chemistry College,Beijing Normal University,Beijing,100875,China
5.State Key Laboratory of Synthetic Chemistry,HKU-CAS Joint Laboratory on New Materials,Department of Chemistry,The University of Hong Kong,Hong Kong,Pokfulam Road 123,Hong Kong
6.Department of Chemistry,Southern University of Science and Technology,Shenzhen,518055,China

Yang，Jian Gong,Song，Xiu Fang,Cheng，Gang,et al. Conformational Engineering of Two-Coordinate Gold(I) Complexes: Regulation of Excited-State Dynamics for Efficient Delayed Fluorescence[J]. ACS Applied Materials & Interfaces,2022,14(11):13539-13549.

Yang，Jian Gong.,Song，Xiu Fang.,Cheng，Gang.,Wu，Siping.,Feng，Xingyu.,...&Li，Kai.(2022).Conformational Engineering of Two-Coordinate Gold(I) Complexes: Regulation of Excited-State Dynamics for Efficient Delayed Fluorescence.ACS Applied Materials & Interfaces,14(11),13539-13549.

Yang，Jian Gong,et al."Conformational Engineering of Two-Coordinate Gold(I) Complexes: Regulation of Excited-State Dynamics for Efficient Delayed Fluorescence".ACS Applied Materials & Interfaces 14.11(2022):13539-13549.