Simple molecular structure design of iridium(III) complexes: Achieving highly efficient non-doped devices with low efficiency roll-off

Wen, Lili; Yu, Jing; Sun, Haizhu; Shan, Guo‐Gang; Zhao, Kai-Yue; Xie, Wenfa; Su, Zhong‐Min

doi:10.1016/j.orgel.2016.05.002

Cited by 20 publications

(9 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We chose 2-(3-methyl-1 H -1,2,4-triazol-5-yl)pyridine ( mtpy ) as an ancillary ligand because of the deprotonation of the azole ring upon coordination, leading to a neutral iridium complex. It also indicates that the introduction of small substituents to HPBI ligands, such as methyl and tert -butyl moieties, results in much more efficient heteroleptic iridium(III) complexes, which achieve higher EL performances and improved efficiency stability compared to that of the parent complex . From a chemical structure standpoint, such small alkyl groups should have little effect on their charge-transporting abilities, although the charge-transporting ability is crucial to the EL efficiency, in particular for nondoped devices.…”

Section: Introductionmentioning

confidence: 99%

Achieving High Performances of Nondoped OLEDs Using Carbazole and Diphenylphosphoryl-Functionalized Ir(III) Complexes as Active Components

et al. 2017

Self Cite

View full text Add to dashboard Cite

Nondoped electroluminescent devices offer advantages over their doped counterparts such as good reproducibility, reduced phase separation between host and guest materials, and potential of lower-cost devices. However, low luminance efficiencies and significant roll-off values are longstanding issues for nondoped devices, and a rational design strategy for the preparation of efficient phosphors is highly desired. In this work, cyclometalated Ir(III) complexes 3CzIr(mtpy), 4CzIr(mtpy), 3POIr(mtpy), and 4POIr(mtpy) bearing carbazole (Cz) or diphenylphosphoryl (PhPO) groups substituted at different positions of 1,2-diphenyl-H-benzimidazole (HPBI) were designed and synthesized. Owing to the steric effects induced by these groups, a significant intermolecular interaction was avoided, thereby reducing self-quenching and triplet-triplet annihilation (TTA) at high brightness. Simultaneously, attached functional moieties manipulate the charge-carrier character and enhance the EL performance of the complexes. Device N3-10, based on 3POIr(mtpy), successfully realized excellent performance and improved efficiency stability, rendering a turn-on voltage of 2.5 V, a maximum current efficiency of 29.7 cd A, and a maximum power efficiency of 31.1 lm W, which are all almost 3-fold higher than that of the control device N-10 based on parent complex. Inspiringly, all of the devices showed reduced efficiency roll-off as luminance increased. To the best of our knowledge, these are good results for green-emitting PHOLEDs using vacuum evaporation techniques, and they provide fundamental insights into the future realization of efficient phosphorescent Ir(III) complexes and corresponding nondoped devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Achieving High Performances of Nondoped OLEDs Using Carbazole and Diphenylphosphoryl-Functionalized Ir(III) Complexes as Active Components

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ir-tBuPBI in dichloromethane solution at room temperature shows a strong absorption band at 310 nm, which is mainly attributed to the spin-allowed ligand-centred π-π* transition. The weak absorption band at wavelengths longer than 340 nm in the lower energy region can be assigned to the LC, MLCT and LLCT transitions of Ir-tBuPBI 22 . The absorption spectrum of an~100-µm-thick Er(F-TPIP) 3 crystal is shown in Fig.…”

Section: Photophysical Propertiesmentioning

confidence: 99%

Enhanced 1.54-μm photo- and electroluminescence based on a perfluorinated Er(III) complex utilizing an iridium(III) complex as a sensitizer

Liu

Lyu

et al. 2020

Light Sci Appl

Self Cite

View full text Add to dashboard Cite

Advanced 1.5-µm emitting materials that can be used to fabricate electrically driven light-emitting devices have the potential for developing cost-effective light sources for integrated silicon photonics. Sensitized erbium (Er 3+) in organic materials can give bright 1.5-µm luminescence and provide a route for realizing 1.5-µm organic light emitting diodes (OLEDs). However, the Er 3+ electroluminescence (EL) intensity needs to be further improved for device applications. Herein, an efficient 1.5-µm OLED made from a sensitized organic Er 3+ co-doped system is realized, where a "traditional" organic phosphorescent molecule with minimal triplet-triplet annihilation is used as a chromophore sensitizer. The chromophore provides efficient sensitization to a co-doped organic Er 3+ complex with a perfluorinatedligand shell. The large volume can protect the Er 3+ 1.5-µm luminescence from vibrational quenching. The average lifetime of the sensitized Er 3+ 1.5-µm luminescence reaches~0.86 ms, with a lifetime component of 2.65 ms, which is by far the longest Er 3+ lifetime in a hydrogen-abundant organic environment and can even compete with that obtained in the fully fluorinated organic Er 3+ system. The optimal sensitization enhances the Er 3+ luminescence by a factor of 1600 even with a high concentration of the phosphorescent molecule, and bright 1.5-µm OLEDs are obtained.

show abstract

“…The solution processed device fabrication method, which suggests the advantages of a simplified low temperature process and low cost based on various printing technologies, is attracting great attention due to the possibility of producing large area panels of OLEDs. Small-molecular hosts and dopants for vacuum phosphorescent OLEDs (PhOLEDs) require modifications to the chemical structure of the material so that they can be dissolved in a common solvent in order to be applied to solution processing. − …”

Section: Introductionmentioning

confidence: 99%

“…1 H NMR (500 MHz, CDCl 3 ): δ (ppm) 8.51 (dd, J = 4.8, 1.6 Hz, 1H), 8.43 (dd, J = 7.7, 1.6 Hz, 1H), 8.33 (d, J = 1.8 Hz, 1H), 8.17 6.69 (dd, J = 17.6, 10.9 Hz, 1H), 5.76−5.65 (m, 1H), 5.58 (s, 2H), 5.23 (dd, J = 10.9, 0.7 Hz, 1H). 13 (14). Following the procedure for the synthesis of compound 10, compound 13 was used as an aromatic amine for the preparation of compound 14.…”

Section: ■ Introductionmentioning

confidence: 99%

Rational Design of Carbazole- and Carboline-Based Polymeric Host Materials for Realizing High-Efficiency Solution-Processed Thermally Activated Delayed Fluorescence Organic Light-Emitting Diode

Hwang

Lee

Jeong

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Recently, various host materials have been developed for solution-processed thermally activated delayed fluorescent organic light-emitting diodes (TADF-OLEDs). Compared with small-molecule hosts, polymeric hosts are advantageous for inducing a uniform distribution and segregation of dopant molecules in the emissive layer without undesired large-scale phase separation. In this study, new polymer hosts were demonstrated, in which a bipolar conjugative moiety consisting of a carbazole (Cz) donor and an α-carboline (α-Cb) acceptor was bound to the polystyrene backbone through a non-conjugated linker. They exhibited high triplet energies of >2.8 eV, and their emission spectra overlapped with the absorption spectrum of a green TADF emitter, which allowed facile energy transfer from the polymeric host to the small-molecule dopants. High device performance was observed, with external quantum efficiencies (EQEs) of 13.65, 17.09, and 17.48% for solution-processed green TADF-OLEDs using PSCzCz, PSCzCb, and PSCbCz, respectively, as hosts for the EML. The EQEs of bipolar host (PSCzCb and PSCbCz)-based devices were higher than those of unipolar host (poly(N-vinylcarbazole) and PSCzCz)-based devices owing to the well-balanced charge-carrier transport. According to these results, the polymeric host bearing a bipolar Cz and α-Cb coupled moiety is a promising material for solution-processable TADF-OLEDs.

show abstract

Simple molecular structure design of iridium(III) complexes: Achieving highly efficient non-doped devices with low efficiency roll-off

Cited by 20 publications

References 74 publications

Achieving High Performances of Nondoped OLEDs Using Carbazole and Diphenylphosphoryl-Functionalized Ir(III) Complexes as Active Components

Achieving High Performances of Nondoped OLEDs Using Carbazole and Diphenylphosphoryl-Functionalized Ir(III) Complexes as Active Components

Enhanced 1.54-μm photo- and electroluminescence based on a perfluorinated Er(III) complex utilizing an iridium(III) complex as a sensitizer

Rational Design of Carbazole- and Carboline-Based Polymeric Host Materials for Realizing High-Efficiency Solution-Processed Thermally Activated Delayed Fluorescence Organic Light-Emitting Diode

Contact Info

Product

Resources

About