Highly Efficient Near‐Infrared Electroluminescence up to 800 nm Using Platinum(II) Phosphors

Wang, Sheng Fu; Yuan, Yi; Wei, Yu‐Chen; Chan, Wei‐Hsiang; Fu, Li-Wen; Su, Borching; Chen, I‐Yun; Chou, Keh-Jiunh; Chen, Po‐Ting; Hsu, Hsiu‐Fu; Ko, Chang‐Lun; Hung, Wen‐Yi; Lee, Chun‐Sing; Chou, Pi‐Tai; Chi, Yun

doi:10.1002/adfm.202002173

Cited by 62 publications

(37 citation statements)

References 53 publications

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“…On this basis, they successfully fabricated NIR-OLEDs achieving a high EQE of 2.18% in the NIR region of 890-930 nm 40 ; added to the merits, these devices exhibited negligible efficiency roll-off for J up to 500 mA cm -2 . In a recent work a non-doped EML consisting of only the Pt(II) emitters enabled OLEDs with EQEs > 10 % at 794 nm (J=100 mA cm −2 ) 48 , with low efficiency roll-off. Compared with host-guest EML, the complexity is reduced when no host is used, yet the required amount of Pt containing emitters is increased.…”

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confidence: 99%

Advances in solution-processed near-infrared light-emitting diodes

et al. 2021

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Near-infrared light-emitting diodes based on solution-processed semiconductors, such as organics, halide perovskites and colloidal quantum dots, have emerged as a viable technological platform for biomedical applications, night vision, surveillance and optical communications. The recently gained increased understanding of the materials structure-photophysical property relationship has enabled the design of efficient emitters leading to devices with external quantum efficiencies exceeding 20%. Despite significant strides made, challenges remain in achieving high radiance, reducing efficiency roll-off, and extending operating lifetime. This review summarizes recent advances on emissive materials synthetic methods and device key attributes that collectively contribute to improved performance of the fabricated light-emitting devices.Light-emitting diodes (LEDs) with emission in the near-infrared (NIR) part of the spectrum (700-2500 nm) (termed as NIR-LEDs) support a large variety of applications such as optical diagnosis and biomedical imaging 1 , optical communication, remote sensing, security, night vision and data storage 2 .The specific application field determines the spectral range of interest within the NIR (Fig. 1a). With regard to in vivo bioimaging, the semi-transparency of biological tissues, oxygenated and deoxygenated blood in specific NIR wavelength regions, also known as biological windows, makes NIR particularly appealing for optical imaging, biomedical sensing and photodynamic therapy. In the field of optical wireless communications, the spectral range is also divided in bands, which correlate with the wavelength regions where optical fibres have small transmission losses 3 . NIR-LEDs are also in demand 3 for security authentication, optogenetics, life-cycle management of crops, light fidelity and surveillance 4 .Common NIR-LEDs are epitaxial heterostructures of III-V inorganic semiconductors (e.g. GaAs, InGaAs, InGaAlAs) [5][6][7] . Commercially available products also employ inorganic phosphors, namely compounds doped with transition metals 8 , or rare-earth trivalent ions 9 . An external quantum efficiency (EQE) of 72% at 880 nm has been reported for an AlGaAs/GaAs/AlGaAs III-V-LED 6 , and 44.5% at 775 nm for LEDs based on LaMgGa 11 O 19 :Cr 3+ phosphors 10 . However, III-V LEDs require post fabrication substrate replacement with high reflective mirror structures to increase their poor power output originating from the refractive index mismatch between those materials (>3.0) 7 and common substrates.Additionally, inorganic phosphors require very high temperature sintering treatment (above 1000 o C).These processing requirements are an obstacle for low-cost, handheld portable implementations. Organic (OSCs) 11 , metal-halide perovskite (HPs) 12 , and colloidal quantum dot (QD) 13 semiconductors, can be processed using low cost and low temperature methods on a wide variety of substrates. For example via solution-based processes such as ink-jet printing, doctor blade and spray coating (Fig. 1b). These...

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confidence: 99%

Advances in solution-processed near-infrared light-emitting diodes

et al. 2021

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“…Organic light-emitting diodes (OLEDs) have been widely used in displays and lighting production [75,76]. Many corresponding red, green, and blue (RGB) emitters have passed rigorous industrial evaluations for commercial applications.…”

Section: Electroluminescencementioning

confidence: 99%

Recent Advances of Near-Infrared (NIR) Emissive Metal Complexes Bridged by Ligands with N- and/or O-Donor Sites

et al. 2021

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Near-infrared (NIR) emissive metal complexes have shown potential applications in optical communication, chemosensors, bioimaging, and laser and organic light-emitting diodes (OLEDs) due to their structural tunability and luminescence stability. Among them, complexes with bridging ligands that exhibit unique emission behavior have attracted extensive interests in recent years. The target performance can be easily achieved by NIR light-emitting metal complexes with bridging ligands through molecular structure design. In this review, the luminescence mechanism and design strategies of NIR luminescent metal complexes with bridging ligands are described firstly, and then summarize the recent advance of NIR luminescent metal complexes with bridging ligands in the fields of electroluminescence and biosensing/bioimaging. Finally, the development trend of NIR luminescent metal complexes with bridging ligands are proposed, which shows an attractive prospect in the field of photophysical and photochemical materials.

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“…Among them, thermally activated delayed fluorescence (TADF) organics [ 2 ] and phosphorescent transition-metal complexes based on the platinum (II) and osmium (II) family [ 3 ] seem to be ideal candidates for efficient NIR organic light-emitting diodes (OLEDs) due to both 25% singlet and 75% triplet excited states being converted into light emissions, which can generally achieve external quantum efficiencies (EQEs) of over 10%. Nevertheless, some negative factors related to these above-mentioned materials (or devices), such as expensive raw materials, several additional auxiliary layers required, adopting mixed host systems based on precise-control concentrations, etc., restrict their further application in NIR-electroluminescent (EL) devices [ 4 , 5 ]. Therefore, it is necessary to explore the challenge of long wavelength-emitting systems with higher and/or more balanced comprehensive characteristics.…”

Section: Introductionmentioning

confidence: 99%

Deep-Red and Near-Infrared Iridium Complexes with Fine-Tuned Emission Colors by Adjusting Trifluoromethyl Substitution on Cyclometalated Ligands Combined with Matched Ancillary Ligands for Highly Efficient Phosphorescent Organic Light-Emitting Diodes

Chen

Tian

et al. 2022

Molecules

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Six novel Ir(C^N)2(L^X)-type heteroleptic iridium complexes with deep-red and near-infrared region (NIR)-emitting coverage were constructed through the cross matching of various cyclometalating (C^N) and ancillary (LX) ligands. Here, three novel C^N ligands were designed by introducing the electron-withdrawing group CF3 on the ortho (o-), meta (m-), and para (p-) positions of the phenyl ring in the 1-phenylisoquinoline (piq) group, which were combined with two electron-rich LX ligands (dipba and dipg), respectively, leading to subsequent iridium complexes with gradually changing emission colors from deep red (≈660 nm) to NIR (≈700 nm). Moreover, a series of phosphorescent organic light-emitting diodes (PhOLEDs) were fabricated by employing these phosphors as dopant emitters with two doping concentrations, 5% and 10%, respectively. They exhibited efficient electroluminescence (EL) with significantly high EQE values: >15.0% for deep red light0 (λmax = 664 nm) and >4.0% for NIR cases (λmax = 704 nm) at a high luminance level of 100 cd m−2. This work not only provides a promising approach for finely tuning the emission color of red phosphors via the easily accessible molecular design strategy, but also enables the establishment of an effective method for enriching phosphorescent-emitting molecules for practical applications, especially in the deep-red and near-infrared region (NIR).

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Highly Efficient Near‐Infrared Electroluminescence up to 800 nm Using Platinum(II) Phosphors

Cited by 62 publications

References 53 publications

Advances in solution-processed near-infrared light-emitting diodes

Advances in solution-processed near-infrared light-emitting diodes

Recent Advances of Near-Infrared (NIR) Emissive Metal Complexes Bridged by Ligands with N- and/or O-Donor Sites

Deep-Red and Near-Infrared Iridium Complexes with Fine-Tuned Emission Colors by Adjusting Trifluoromethyl Substitution on Cyclometalated Ligands Combined with Matched Ancillary Ligands for Highly Efficient Phosphorescent Organic Light-Emitting Diodes

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