A simple and efficient approach toward deep-red to near-infrared-emitting iridium(<scp>iii</scp>) complexes for organic light-emitting diodes with external quantum efficiencies of over 10%

Chen, Zhao; Zhang, Hongyang; Wen, Dawei; Wu, Wenhai; Zeng, Qingguang; Chen, Shuming; Wong, Wai Yeung

doi:10.1039/c9sc05492h

Cited by 107 publications

(93 citation statements)

References 40 publications

(93 reference statements)

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“…Therefore, some electron‐withdrawing CN groups are introduced into the organic framework of TFB to achieve two unreported polymers (Figure 1a). [ 34,35 ] The 2‐cyanopropan‐2‐yl (CNPr) group was chosen for its unique features, such as weak electron‐withdrawing property and no active hydrogen (α– H ) atoms. The former decreases the electrons on the polymer chain, resulting in a much more stabilized HOMO energy level.…”

Section: Resultsmentioning

confidence: 99%

An Efficient Hole Transporting Polymer for Quantum Dot Light‐Emitting Diodes

Chen

Zhan

et al. 2021

Adv Materials Inter

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Ideal hole transporting polymers used in quantum dot (QD) light‐emitting diodes (QLEDs) should possess the features such as high conductivities and stabilized highest occupied molecular orbitals (HOMOs). Herein, an efficient polymer (named CNPr‐TFB) is achieved by rationally adding a relatively weak electron‐withdrawing group (2‐cyanopropan‐2‐yl, CNPr) on a TFB like hole transporting polymer. CNPr‐TFB exhibits a superior hole conductivity and much more stabilized HOMO in comparison with TFB. Therefore, much more holes are delivered into the QD emissive layers and a balanced recombination of electron and hole in the QLEDs is achieved. The external quantum efficiencies of the red, green, blue, and white QLEDs made by CNPr‐TFB as the hole transporting layer (HTL) are 20.7%, 16.6%, 11.3%, and 15.0%, respectively, which are increased by 1.4–2.3 times in comparison with those of devices based on the commonly used TFB HTL. Meanwhile, the CNPr‐TFB‐based QLEDs also exhibit longer operation lifetimes than those of devices using the TFB HTL. These results confirm that CNPr‐TFB with the features of high conductivity and stabilized HOMO can be an excellent HTL material for the QLED applications

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Section: Resultsmentioning

confidence: 99%

An Efficient Hole Transporting Polymer for Quantum Dot Light‐Emitting Diodes

Chen

Zhan

et al. 2021

Adv Materials Inter

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“…Many works have been done to the design and preparation of noble metal-based PTMCs toward highly efficient OLEDs. [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).…”

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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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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“…We and other group have demonstrated that the cyano group (À CN) is of electron withdrawing property which can lower the energy level of the lowest unoccupied molecular orbital (LUMO) and tune the molecular emission spectra. [44,47] Accordingly, the À CN group was anchored to the Nz to push the emission to the longer wavelength region and the resultant molecule is abbreviated as PINzPCN. It showed similar PLQY with PINzP in both doped and nondoped films but more redshifted emission.…”

Section: Introductionmentioning

confidence: 99%

“…The doped device of PINzP exhibited similar EL spectra to nondoped device but much improved efficiency with a maximum EQE of 6.96%. We and other group have demonstrated that the cyano group (−CN) is of electron withdrawing property which can lower the energy level of the lowest unoccupied molecular orbital (LUMO) and tune the molecular emission spectra [44,47] . Accordingly, the −CN group was anchored to the Nz to push the emission to the longer wavelength region and the resultant molecule is abbreviated as PINzPCN.…”

Section: Introductionmentioning

confidence: 99%

Efficient Red Electroluminescence From Phenanthro[9,10‐d]imidazole‐Naphtho[2,3‐c][1,2,5]thiadiazole Donor‐Acceptor Derivatives

Tang

Liu

et al. 2021

Chemistry An Asian Journal

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Red emission is one of the three primary colors and is indispensable for full color displays. Fluorescent materials that can generate efficient red electroluminescence (EL) are limited and need to be developed. In this work, we report efficient red emitters based on phenanthro[9,10-d]imidazolenaphtho[2,3-c][1,2,5]thiadiazole donor-acceptor derivatives. The molecules, abbreviated as PINzP and PINzPCN, exhibited high photoluminescence quantum yield (PLQY) up to unity in doped films. They can also reach a relatively high PLQY of 30% in neat films. PINzP and PINzPCN were capable of generating efficient red EL in doped devices with a maximum external quantum efficiency (EQE) of 6.96% and 5.92%, respectively.

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A simple and efficient approach toward deep-red to near-infrared-emitting iridium(iii) complexes for organic light-emitting diodes with external quantum efficiencies of over 10%

Abstract: The simplest and the most efficient deep-red to near-infrared-emitting emitters afford a new record external quantum efficiency for iridium(iii) complex based deep-red to near-infrared organic light-emitting diodes.

Cited by 107 publications

References 40 publications

An Efficient Hole Transporting Polymer for Quantum Dot Light‐Emitting Diodes

An Efficient Hole Transporting Polymer for Quantum Dot Light‐Emitting Diodes

Phosphorescent Manganese(II) Complexes and Their Emerging Applications

Efficient Red Electroluminescence From Phenanthro[9,10‐d]imidazole‐Naphtho[2,3‐c][1,2,5]thiadiazole Donor‐Acceptor Derivatives

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