Single‐Molecular White‐Light Emitters and Their Potential WOLED Applications

Chen, Zhao; Ho, Cheuk Lam; Wang, Liqi; Wong, Wai Yeung

doi:10.1002/adma.201903269

Cited by 239 publications

(176 citation statements)

References 190 publications

(427 reference statements)

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“…It is suggested that the emission originates from the π-π stacking system induced aggregation, and ClCbz has a relatively more effective donor-acceptor interaction than HCbz, MeCbz and SCbz in solid state (ESI). [19] The calculation results further support this suggestion (ESI). Quantum yields of all HCbz derivatives in the solid states were smaller than the values in THF, respectively.…”

Section: Scheme 4 the Suggested Two-step Reaction Pathway For Radicalsupporting

confidence: 55%

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃

et al. 2020

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of main observation and conclusion A facile synthesis, functionalization, and emission property of N-doped carbon-rich halogenated compound 3,6,12,15-tetrachloro-9-phenyl-9H-tetrabenzo[a,c,g,i]carbazole (ClCbz) was reported. Cost-effective FeCl 3 catalyst serves to break eight C-H bonds of 1,2,3,4,5-pentaphenylpyrrole (1) and subsequently construct two CC and four C-Cl bonds in one pot with a high yield of up to 75%.

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Section: Scheme 4 the Suggested Two-step Reaction Pathway For Radicalsupporting

confidence: 55%

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃

et al. 2020

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“…[77][78][79][80][81][82] So far, many commercialized emitters are based on these phosphors (such as iridium(III) complex). [83][84][85][86][87][88] However, these noble metals often have some disadvantages (such as high cost and low abundance in nature). The exploration of low-cost, relatively abundant, and less-toxic phosphorescent manganese(II) complexes could be the key to solve this problem.…”

Section: Organic Light-emitting Diodesmentioning

confidence: 99%

Phosphorescent Manganese(II) Complexes and Their Emerging Applications

Tao

Liu

Wong

2020

Advanced Optical Materials

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100

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light-emitting device (OLED) in 1998, [1] phosphorescent transition-metal complexes, especially for noble metal-based ones (e.g., iridium(III), platinum(II), etc.) as triplet emitters toward highly efficient organic electroluminescence, have aroused extensive attention. [15-21] Owing to strong spin-orbit coupling effect, these complexes may use both singlet and triplet excitons to greatly enhance the efficiency of OLED, breaking the upper limit of the conventional fluorescent device efficiency. Due to their unique properties of excited states, they also have extended their applications in other fields, for instance, catalysis, organic solar cells, organic memory devices, biological sensing and imaging, photodynamic therapy, information recording, and security protection, etc. [22-27] Although extensive works have been done to the design and preparation of phosphorescent materials based on noble metals, these noble metals usually have some disadvantages (such as high cost and low abundance in nature), thereby limiting their practical applications. The relatively abundant and cheap PTMCs of low toxicity have drawn considerable interests very recently. [4,23,24,28-31] Many kinds of non-noble metal-based PTMCs such as copper(I), tungsten(VI), and manganese(II) complexes have emerged rapidly. [4,23-25,28-31] Phosphorescent manganese(II) complexes show great potentials in many applications, due to their features including highly efficient phosphorescence, flexible design in molecular structure, ease of synthesis, and rich physical properties (e.g., triboluminescence, stimuli-responsivity, etc.). [24,25a,32-36] Compared with the noble metals, manganese element with an atomic number of 25 has abundant reserves, is environmentally friendly and inexpensive. Moreover, it has richer valence and coordination mode, which has been widely used in the fields of catalysis, ferroelectric, and magnetic materials. [37-39] Among the various valence states of manganese ion, the divalent manganese ion having a 3d 5 electron configuration has a 4 T 1 − 6 A 1 radiative transition closely related to the crystal field strength. The crystal field strength in the metal complex highly depends on the chemical structure of the ligand and the coordination number. These features make the manganese(II) complexes having rich photophysical properties. By regulating the ligand structure, the organic counterion and the coordination number of the manganese(II) complex, the green, yellow, orange, red, or even near-infrared phosphorescence can be achieved. [23-25,36,40] It Phosphorescent manganese(II) complexes are emerging as a new generation of phosphorescent materials showing great potentials in many applications, owing to their unique features including highly efficient phosphorescence, diverse structural/molecular design, and ease of synthesis, structural diversity, rich physical properties (e.g., triboluminescence, stimuli-responsivity, etc.), high abundance, and low cost. The research on phosphorescent manganese(II) complexes is just in its infancy...

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“…[ 21 ] However, the luminescent color are environmentally sensitive, and could response to various external stimuli, [ 30 ] inferring vulnerable interact‐force system between molecules. Consequently, although highly reproducible white emission can be achieved in single‐doped PhOLEDs by confining the monomeric and excimeric emission, [ 31,32 ] the precisely tuned emission might have unexpected color shifting under current change. [ 17,33 ] Nonetheless, in spite of great importance for practical application.…”

Section: Figurementioning

confidence: 99%

Tetradentate Pt(II) Complexes for Spectrum‐Stable Deep‐Blue and White Electroluminescence

Zhu

Xie

Qian

et al. 2020

Advanced Optical Materials

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and optoelectronic devices. [5,6] Chelated Ir(III) and Pt(II) complexes can acquire high spin-orbit coupling effects, thereby ideally suiting for phosphorescent organic light-emitting diodes (PhOLEDs). [7-9] These complexes can efficiently harness both singlet and triplet excitons and afford 100% internal quantum efficiency in electroluminescent devices. [10,11] Ir(III) complexes are in octahedral-field structure and chelated with three monoanionic bidentate ligands with high-lying π* orbitals, leading to efficient spin-flip triplet transition in metal-to-ligand charge transfer (3 MLCT) characteristic at ambient condition. [12,13] On the other hand, tetradentate square-planar Pt(II) complexes have received considerable attention in terms of their high efficiency, [14,15] stability [16,17] and color purity [18,19] in electroluminescent devices. Recent studies on those Pt(II) complexes revealed highly admixed triplet configurations interacting among regional substates, which dominate the emission in photo-and electroluminescence. [20-23] Furthermore, due to their environmentsensitive property in the lowest triplet excited state (T 1), the emission spectra of the complexes are manageable according to certain circumstance. [24] Bearing in mind the nature of the Pt(II) complexes, we infer it is possible to tune the emission from narrow blue to broad white via triplet managing, [22] which is concurrently challenging in molecular design and desirable in display and lighting applications. Unlike the Ir(III) complexes in closed octahedral geometry, Pt(II) chelated molecules have open square-planar structures, thus are easy to have inter-and intra-molecular excited-state perturbation, such as d 8 …d 8 (Pt…Pt), π…π, and hydrogen bond. [25,26] Generally, Pt…Pt interaction leads to a new metalmetal-to-ligand charge transfer (MMLCT) transition state involving a filled Pt…Pt antibonding orbital and a high-lying π* orbital on the ligand. [27,28] Their semiconducting and longwavelength luminescent properties can be utilized for fabricating high-performance light-emitting field-effect transistors and near-infrared OLEDs. [5,29] Molecular stacking via π-π and hydrogen bonds could also form excimer, giving new emissions in lower energy band. [21] However, the luminescent color A new class of tetradentate Pt(II) complexes, Pt(pzpyOczpy-iPr) and Pt(pzpyOczpy-mesi), enabling fabrication of deep-blue and white phosphorescent devices, is successfully synthesized and fully characterized. Their photoluminescent quantum yields in dichloromethane are over 90% with short decay lifetimes less than 4.0 µs. Under low doping concentration, the emission is governed by ligand-centered triplet transition state (3 LC, 3 π cz *→π cz) on carbazole group, rendering narrow blue emission with full width at half-maximum (FWHM) less than 45 nm. When increasing the doping concentration, expanded monomeric and excimeric emissions are demonstrable, displaying broad white emission with FWHM up to 152 nm. Devices fabricated with 2 wt% dopant in DPEPO host achiev...

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Single‐Molecular White‐Light Emitters and Their Potential WOLED Applications

Cited by 239 publications

References 190 publications

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃

Phosphorescent Manganese(II) Complexes and Their Emerging Applications

Tetradentate Pt(II) Complexes for Spectrum‐Stable Deep‐Blue and White Electroluminescence

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Single‐Molecular White‐Light Emitters and Their Potential WOLED Applications

Cited by 239 publications

References 190 publications

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl3

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl3

Phosphorescent Manganese(II) Complexes and Their Emerging Applications

Tetradentate Pt(II) Complexes for Spectrum‐Stable Deep‐Blue and White Electroluminescence

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Product

Resources

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Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃

Synthesis of π‐Extended Carbazoles via One‐Pot C—C Coupling and Chlorination Promoted by FeCl₃