Achieving High‐Performance Pure‐Red Electrophosphorescent Iridium(III) Complexes Based on Optimizing Ancillary Ligands

Liang, Baoyan; Yu, Z.-W.; Zhuang, Xuming; Wang, Jiaxuan; Wei, Jinbei; Ye, Kaiqi; Zhang, Zuolun; Liu, Yu; Wang, Yue

doi:10.1002/chem.201905690

Cited by 13 publications

(5 citation statements)

References 42 publications

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“…The iridium(III) centers of these three complexes are coordinated with the same two main ligands (HmPBI or HtbPBI) and an ancillary ligand (HBIQ or HBISQ), resulting in a distorted-octahedral coordination geometry. In all cases, these molecular structures contained trans -nitrogen and cis -metalated carbon dispositions, similarly to the other previously reported analogous phosphors. − As shown in Table S1 in the Supporting Information, the Ir1–N1 and Ir1–N3 bond lengths of all three complexes are slightly shorter than the Ir1–N5 and Ir1–N6 bond lengths due to the trans disposition of the main ligands. In addition, the two Ir–C bonds of Ir-3 and Ir-4 have almost the same length, while the Ir1–C21 bond length is longer than the Ir1–C1 bond length of Ir-1 due to the influence of the ancillary ligand HBIQ.…”

Section: Resultssupporting

confidence: 86%

High-Performance and Stable Warm White OLEDs Based on Orange Iridium(III) Phosphors Modified with Simple Alkyl Groups

et al. 2020

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Phosphorescent organic light-emitting diodes (OLEDs) with high electroluminescence (EL) efficiency and low efficiency roll-off are urgently required to meet the continuously increasing market need in lighting industry fields. There is an urgent demand for phosphorescent emitters with excellent photoluminescence quantum yields (PLQYs) to realize a high EL performance of OLEDs. In this work, four new orange phosphorescent iridium(III) emitters, namely Ir-1−Ir-4, were designed and synthesized successfully, in which functionalized 1,2-diphenylbenzimidazole and conjugated quinoline-benzimidazole moieties are employed as the main ligands and ancillary ligands, respectively. The obtained phosphors show relatively high efficiency and broad full width at half-maximums (FWHMs) of about 110 nm, which are favorable for constructing high-quality white OLEDs. The optimized monochromatic orange-emitting OLED of Ir-1 shows a maximum current efficiency (CE) of 27.2 cd A −1 , a power efficiency of 24.0 lm W −1 , and an external quantum efficiency (EQE) of 10.6%. A two-color OLED employing Ir-1 as the orangeemitting layer shows a maximum brightness of 43980 cd m −2 , a CE of 27.7 cd A −1 , a PE of 21.8 lm W −1 , an EQE of 11.3%, and a low CE efficiency roll-off ratio of 7.9%. Moreover, this device displays warm white emission with CIE coordinates of (0.39, 0.43) at 7 V and high color stability with a CIE variation of (0.003, 0.001).

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Section: Resultssupporting

confidence: 86%

High-Performance and Stable Warm White OLEDs Based on Orange Iridium(III) Phosphors Modified with Simple Alkyl Groups

et al. 2020

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“…The chromophore ancillary ligands, like amidinate and amide derivatives were often used in red-emitting Ir(III) complexes ( Kabir et al., 2020 ; Lai and Teets, 2019 ; Lai et al., 2018 ; Liang et al., 2020 ; Su et al., 2020 ). Recently, Teets et al.…”

Section: Molecular Designs For Nir-emitting Ir(iii) Complexesmentioning

confidence: 99%

Near-infrared emitting iridium complexes: Molecular design, photophysical properties, and related applications

Zhang

Qiao

2021

iScience

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Summary Organic light-emitting diodes (OLEDs) have become popular displays from small screens of wearables to large screens of televisions. In those active-matrix OLED displays, phosphorescent iridium(III) complexes serve as the indispensable green and red emitters because of their high luminous efficiency, excellent color tunability, and high durability. However, in contrast to their brilliant success in the visible region, iridium complexes are still underperforming in the near-infrared (NIR) region, particular in poor luminous efficiency according to the energy gap law. In this review, we first recall the basic theory of phosphorescent iridium complexes and explore their full potential for NIR emission. Next, the recent advances in NIR-emitting iridium complexes are summarized by highlighting design strategies and the structure-properties relationship. Some important implications for controlling photophysical properties are revealed. Moreover, as promising applications, NIR-OLEDs and bio-imaging based on NIR Ir(III) complexes are also presented. Finally, challenges and opportunities for NIR-emitting iridium complexes are envisioned.

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“…The operation voltages of devices E2-E4 recorded at 5 mW/cm 2 were respectively 5.2 V, 5.9 V, and 6.2 V. Clearly, device E2 only required 5.2 V operation voltage, thus meeting practical usage requirements, illustrating the application-appropriateness of this design. Compared with previously developed devices (target wavelength ranges 630-690 nm) in terms of the FWHM values of the EL spectrum, our designed OLEDs provide excellent device performance, including the most extended EL spectral profiles, low turn-on voltage, and adequate efficiency [28][29][30][31][32][33][34]. Figure 7 shows schematic images of the PBM patch.…”

Section: Structures Of the Hilmentioning

confidence: 99%

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

Chen

Huang

et al. 2021

Materials

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Organic light-emitting diodes (OLEDs) used as phototherapy light sources require sufficient spectral distribution in the effective wavelength ranges and low operating voltages. Herein, a double emitting layer structure consisting of a red-emitting Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad electroluminescence spectrum. An efficient TCTA:CN-T2T exciplex system was used as the host of the emitting layer, facilitating effective energy transfer from the exciplex host to the red and deep-red phosphors. The materials used in the exciplex host were also used as the carrier transport layers to eliminate the energy barriers and thus increase the current density. The hole injection layer structures were varied to examine the hole injection capabilities and the carrier balance. The resulting optimized phosphorescent OLEDs with a broad spectral profile exhibit a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 19.1% (10.2 cd/A and 13.8 lm/W). The proposed device only needs 5.2 V to achieve a power density of 5 mW/cm2, implying that the device could be driven via two series-connected button cell batteries. These results illustrate the feasibility of our design concepts and demonstrate the realization of a portable and lightweight OLED phototherapy light source.

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Achieving High‐Performance Pure‐Red Electrophosphorescent Iridium(III) Complexes Based on Optimizing Ancillary Ligands

Cited by 13 publications

References 42 publications

High-Performance and Stable Warm White OLEDs Based on Orange Iridium(III) Phosphors Modified with Simple Alkyl Groups

High-Performance and Stable Warm White OLEDs Based on Orange Iridium(III) Phosphors Modified with Simple Alkyl Groups

Near-infrared emitting iridium complexes: Molecular design, photophysical properties, and related applications

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

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