Deep-red and near-infrared light-emitting electrochemical cells employing perovskite color conversion layers with EQE &gt;10%

Su, Yi-Hua; Huang, Yu‐Ting; Luo, Dian; Liu, Shun‐Wei; Yang, Zu‐Po; Lu, Chin‐Wei; Chang, Chih-Hao; Su, Hai‐Ching

doi:10.1039/d2tc03813g

Cited by 11 publications

(15 citation statements)

References 60 publications

(126 reference statements)

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“…30 and 40%, respectively) was significantly lower than that (γ >70%) reported for the state-of-the-art LECs employing iridium complexes (EQE >10%). 59,60 However, the device efficiencies of the proposed LECs based on gold complexes were either higher than 61,62 or comparable with 63,64 those of the reported LECs employing copper complexes exhibiting similar emission spectra and PLQYs. Compared with ruthenium complexes, the proposed gold complexes showed comparable EL efficiencies, but the yellow EL emission spectra of gold complexes were beneficial in obtaining higher current efficiencies (cd A −1 ) and power efficiencies (lm W −1 ) due to better spectral overlap with the spectral sensitivity of human eyes.…”

Section: ■ Results and Discussionsupporting

confidence: 55%

“…The degree of carrier balance of the LECs based on complex 1PF 6 and 3 (γ = ca. 30 and 40%, respectively) was significantly lower than that (γ >70%) reported for the state-of-the-art LECs employing iridium complexes (EQE >10%). , However, the device efficiencies of the proposed LECs based on gold complexes were either higher than , or comparable with , those of the reported LECs employing copper complexes exhibiting similar emission spectra and PLQYs. Compared with ruthenium complexes, the proposed gold complexes showed comparable EL efficiencies, but the yellow EL emission spectra of gold complexes were beneficial in obtaining higher current efficiencies (cd A –1 ) and power efficiencies (lm W –1 ) due to better spectral overlap with the spectral sensitivity of human eyes. , These comparison results indicate that similar to iTMCs other than the iridium complexes, more sophisticated studies on enhancing the PLQYs of gold complexes and improving the carrier balance of the LECs based on gold complexes would be required for them to reach the device performance of LECs based on iridium complexes.…”

Section: Resultsmentioning

confidence: 93%

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Biphenyl Au(III) Complexes with Phosphine Ancillary Ligands: Synthesis, Optical Properties, and Electroluminescence in Light-Emitting Electrochemical Cells

et al. 2023

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A series of ten cationic complexes of the general formula [(C^C)Au(P^P)]X, where C^C = 4,4′-di-tert-butyl-1,1′-biphenyl, P^P is a diphosphine ligand, and X is a noncoordinating counteranion, have been synthesized and fully characterized by means of chemical and X-ray structural methods. All the complexes display a remarkable switch-on of the emission properties when going from a fluid solution to a solid state. In the latter, long-lived emission with lifetime τ = 1.8–83.0 μs and maximum in the green-yellow region is achieved with moderate to high photoluminescence quantum yield (PLQY). This emission is ascribed to an excited state with a mainly triplet ligand-centered (3LC) nature. This effect strongly indicates that rigidification of the environment helps to suppress nonradiative decay, which is mainly attributed to the large molecular distortion in the excited state, as supported by density functional theory (DFT) and time-dependent DFT (TD-DFT) computation. In addition, quenching intermolecular interactions of the emitter are avoided thanks to the steric hindrance of the substituents. Emissive properties are therefore restored efficiently. The influence of both diphosphine and anion has been investigated and rationalized as well. Using two complexes as examples and owing to their enhanced optical properties in the solid state, the first proof-of-concept of the use of gold(III) complexes as electroactive materials for the fabrication of light-emitting electrochemical cell (LEC) devices is herein demonstrated. The LECs achieve peak external quantum efficiency, current efficiency, and power efficiency up to ca. 1%, 2.6 cd A–1, and 1.1 lm W–1 for complex 1PF6 and 0.9%, 2.5 cd A–1, and 0.7 lm W–1 for complex 3, showing the potential use of these novel emitters as electroactive compounds in LEC devices.

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Section: ■ Results and Discussionsupporting

confidence: 55%

Section: Resultsmentioning

confidence: 93%

Biphenyl Au(III) Complexes with Phosphine Ancillary Ligands: Synthesis, Optical Properties, and Electroluminescence in Light-Emitting Electrochemical Cells

et al. 2023

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“…To further enhance device efficiency, diffusive substrates were employed to extract the light trapped in the substrate. [23,48,55] We fabricated the same white LECs on the substrates embedding a diffusive layer between the glass substrate and the…”

Section: Chemistry-a European Journalmentioning

confidence: 99%

“…The thick emissive layer was employed to optimize the device efficiency. [23,48] Finally, a silver top contact was deposited by thermal evaporation in a vacuum chamber (ca. 10 À 6 torr).…”

Section: Fabrication Of Diffusive Substratesmentioning

confidence: 99%

White Light‐Emitting Electrochemical Cells Employing Phosphor‐Sensitized Thermally Activated Delayed Fluorescence to Approach All‐Phosphorescent Device Efficiencies

Chen

Huang

Luo

et al. 2023

Chemistry A European J

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Solid-state light-emitting electrochemical cells (LECs) show promising advantages of simple device architecture, low operation voltage, and insensitivity to the electrode work functions such that they have high potential in low-cost display and lighting applications. In this work, novel white LECs based on phosphor-sensitized thermally activated delayed fluorescence (TADF) are proposed. The emissive layer of these white LECs is composed of a blue-green phosphorescent host doped with a deep-red TADF guest. Efficient singlet-to-triplet intersystem crossing (ISC) on the phosphorescent host and the subsequent Förster energy transfer from the host triplet excitons to guest singlet excitons can make use of both singlet and triplet excitons on the host. With the good spectral overlap between the host emission and the guest absorption, 0.075 wt.% guest doping is sufficient to cause substantial energy transfer efficiency (ca. 40 %). In addition, such a low guest concentration also reduces the self-quenching effect and a high photoluminescence quantum yield of up to 84 % ensures high device efficiency. The phosphor-sensitized TADF white LECs indeed show a high external quantum efficiency of 9.6 %, which is comparable with all-phosphorescent white LECs. By employing diffusive substrates to extract the light trapped in the substrate, the device efficiency can be further improved by ca. 50 %. In the meantime, the intrinsic EL spectrum and device lifetime of the white LECs recover since the microcavity effect is destroyed. This work successfully demonstrates that the phosphor-sensitized TADF white LECs are potential candidates for efficient white light-emitting devices.

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“…Several approaches have been developed to increase the device's lifetimes. The inherent instability of iTMC is attributed to a ligand exchange reaction with the residue of solvent or water molecules during the device operation, forming a non-luminescent complex [14][15][16][17][18][19][20][21][22][23][24][24][25][26] . Therefore, an efficient way to increase the stability of iTMC can be limiting the access of foreign substances to the metal center.…”

mentioning

confidence: 99%

Phenanthroimidazole as molecularly engineered switch for efficient and highly long-lived light-emitting electrochemical cell

Bideh

Sousaraei

Arani

2023

Sci Rep

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Light-emitting electrochemical cells (LECs) based on Ir(III) complexes owing to the superior advantages exhibit high potential for display and lighting applications. Herein, a series of Ir(III) complexes based on phenanthroimidazole (PI) as an ancillary ligand were synthesized to achieve efficient and highly stable yellow-to-orange LEC devices with fast response. These complexes exhibit appropriate electrochemical stability and significant suppression of concentration quenching in the thin films compared to the archetype complex. The fabricated LECs showed remarkably long device lifetimes over 1400 and 2100 h and external quantum efficiency of 2 and 3% for yellow and orange-LECs, respectively. The obtained t1/2 for yellow LEC is much higher than archetype [Ir(ppy)2(phen)]+ and their phenanthroline-based analogues reported so far. The incorporation of an ionic tethered functional group on PI, improved the mobility of the emissive layer and reduced the device turn-on time by 75–88%. This study shows a facile functionalization and characterization of the PI ligand as well as its potential application in optoelectronic devices (OLED).

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Deep-red and near-infrared light-emitting electrochemical cells employing perovskite color conversion layers with EQE >10%

Abstract: Solid-state light-emitting electrochemical cells (LECs) exhibit high potential applications in consumer electronics due to their promising advantages of solution-processable simple device architecture, low-voltage operation and compatibility with inert metal electrodes....

Cited by 11 publications

References 60 publications

Biphenyl Au(III) Complexes with Phosphine Ancillary Ligands: Synthesis, Optical Properties, and Electroluminescence in Light-Emitting Electrochemical Cells

Biphenyl Au(III) Complexes with Phosphine Ancillary Ligands: Synthesis, Optical Properties, and Electroluminescence in Light-Emitting Electrochemical Cells

White Light‐Emitting Electrochemical Cells Employing Phosphor‐Sensitized Thermally Activated Delayed Fluorescence to Approach All‐Phosphorescent Device Efficiencies

Phenanthroimidazole as molecularly engineered switch for efficient and highly long-lived light-emitting electrochemical cell

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