Design and performance study of high efficiency/low efficiency roll-off/high CRI hybrid WOLEDs based on aggregation-induced emission materials as fluorescent emitters

Xu, Zheng; Gu, Jiabao; Huang, Jian; Lin, Chengwei; Li, Yuanzhao; Yang, Dezhi; Qiao, Xianfeng; Qin, Anjun; Zhao, Zujin; Tang, Ben Zhong; Ma, Dongge

doi:10.1039/c9qm00539k

Cited by 19 publications

(8 citation statements)

References 32 publications

(36 reference statements)

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“…As shown in Figure B, the emission of 2 was quenched by Ir(MDQ) 2 acac with a reduction of the lifetime from 1.88 to 1.35 μs, indicating that energy transfers from 2 to Ir(MDQ) 2 acac. To further confirm the emission mechanism in devices, a series of the hole- and electron-only devices are prepared to investigate the impact of the dopant on carrier-transporting processes . The structures of single-carrier devices and current density–voltage characteristics are displayed in Figures S14 and B,C.…”

Section: Resultsmentioning

confidence: 99%

“…To further confirm the emission mechanism in devices, a series of the hole-and electron-only devices are prepared to investigate the impact of the dopant on carriertransporting processes. 62 The structures of single-carrier devices and current density−voltage characteristics are displayed in Figures S14 and 7B,C. When FIrpic is doped into 26DCzPPy, the hole currents slightly decrease but do not change in the electron current.…”

Section: Resultsmentioning

confidence: 99%

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Rational Design of Ir(III) Phosphors to Strategically Manage Charge Recombination for High-Performance White Organic Light-Emitting Diodes

et al. 2022

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Constructing high-quality white organic light-emitting diodes (WOLEDs) remains a big challenge because of high demands on the electroluminescence (EL) performance including high efficiency, excellent spectral stability, and low roll-off simultaneously. To achieve effective energy transfer and trap-assisted recombination in the emissive layer, herein, four Ir(III) phosphors, namely, m OMe-Ir-PI (1), p OMe-Ir-PI (2), m OMe-Ir-PB (3), and p OMe-Ir-PB (4), were strategically designed via simple regulation of the substituent moiety and π conjugation of the chelated ligands. Their photophysical and EL properties were systematically investigated. When these phosphors are employed as doped emitters, the monochromic green organic light-emitting diodes not only exhibit a superior performance with the characteristics of 50.2 cd A–1, 39.2 lm W–1, and 15.1%, but also maintain a negligible roll-off ratio of 0.2% at 1000 cd m–2, which are better than those of commercial green Ir(ppy)2acac and Ir(ppy)3 in the same device configuration. Inspired by these outstanding performances, we successfully fabricated the warm WOLED utilizing 2 as a green component, affording a peak efficiency of 42.0 cd A–1, 29.3 lm W–1, and 18.6% and retaining at 39.9 cd A–1, 23.7 lm W–1, and 17.4% even at 1000 cd m–2. The results herein demonstrate the superiority of the molecular design and propose a simple method toward the development of promising Ir(III) phosphors for high-efficiency WOLEDs.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Rational Design of Ir(III) Phosphors to Strategically Manage Charge Recombination for High-Performance White Organic Light-Emitting Diodes

et al. 2022

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“…[ 18,19 ] Thus, hybrid combinations, that is, leveraging TADF/phosphorescence, fluorescence/phosphorescence or fluorescence/TADF emitters, are also proposed for WOLEDs. [ 20–25 ]…”

Section: Introductionmentioning

confidence: 99%

All‐Fluorescence White Organic Light‐Emitting Diodes Exceeding 20% EQEs by Rational Manipulation of Singlet and Triplet Excitons

Tang

et al. 2020

Adv Funct Materials

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White organic light-emitting diodes (WOLEDs) composed of conventional fluorophores possess color purity, low efficiency roll-off, and rare metal absence, but suffer from theoretical limits due to the lack of triplet utilization. Due to the different diffusion distance for singlets and triplets, multiple Förster resonance energy transfer (FRET) channels can be adequately built up. Herein, besides the complementary component, a blue fluorescence layer, hosted by pure hydrocarbon material SF4-TPE, is put forward as the spatial exciton manipulating layer to rationally allocate singlets and triplets to the corresponding channels. Hence, singlets are captured by the blue fluorophore, diffused triplets subsequently undergo energy resonance between the blue fluorophore and green assistant, and up-conversion effect for eventual emission from the yellow fluorophore. Owing to the utilization of singlets and triplets, all-fluorescence WOLEDs exhibit high efficiency exceeding 20%, with slight efficiency roll-off even under high luminance of 5000 cd cm −2 . Moreover, CIE coordinates can be surrounding and precisely inside the American National Standard Institute (ANSI) quadrangles, as well as outstanding color stability (ΔCIE-(x, y) within (0.001, 0.012)) from 300 to 13000 cd cm −2 .The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201910633.white emission and achieved a power efficiency (PE) of 0.5 lm W −1 . However, due to the deficiency of utilizing triplets, the WOLEDs based on all-fluorescence emitters can hardly break the 25% theoretical limitation of internal quantum efficiency (IQE). [4,5] Alternatively, the exploitation of rare metallic phosphorescent complexes and thermally activated delayed fluorescence (TADF) emitters that can harvest all the electrogenerated excitons [6] become the fundamental and mainstream study on constructing high-efficiency WOLEDs in the past decade. [2,[7][8][9][10][11][12][13][14][15] However, allphosphorescence WOLEDs still suffer from the intrinsic deficiencies including rare metal reliance, color impurity, and fragile operational stability for blue phosphors, [16,17] while all-TADF WOLEDs present severe efficiency roll-off because of triplet-triplet annihilation (TTA) at high luminance and unsatisfactory Commission International de l'Eclairage (CIE) coordinates deviation. [18,19] Thus, hybrid combinations, that is, leveraging TADF/ phosphorescence, fluorescence/phosphorescence or fluorescence/TADF emitters, are also proposed for WOLEDs. [20][21][22][23][24][25] Recently, the efficiency of fluorescence OLEDs can be dramatically improved by TADF assistant technique, in which TADF materials play as "triplet exciton pump" (not emitter) to up-converse triplets in conventional fluorescence emitters to approach 100% IQEs. [26] This technique has made promising progress in monochromatic emitting dyes with relatively low-lying states, such as green, yellow, and red fluorophores. [27][28][29] Thus, it seems reasonable and accessibl...

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“…Then, a TADF material 10-(4-(dimesitylboranyl)phenyl)-10 H -phenothiazine PTZMes 2 B was selected as the host for PO-01 owing to the suitable T 1 and bipolar transport character. According to previous reports, PTZMes 2 B could not only exhibit green emission with superior efficiency in nondoped OLEDs but also was capable to be utilized as the appropriate host for phosphors in phosphorescent OLEDs and hybrid WOLEDs. − In addition, because T 1 of PyPPA was about 2.17 eV, which was lower than that of PO-01 (2.20 eV), a high-T 1 interlayer was needed to be inserted between the blue layer and orange layer to avoid undesired energy transfer from phosphors to fluorophors. In our previous report, a high-T 1 mixed interlayer composing an electron-transporting material and a hole-transporting material was beneficial to achieve satisfactory device performance owing to high electron and hole mobility together with the suitable energy levels of LUMO and HOMO.…”

Section: Results and Discussionmentioning

confidence: 99%

Pyrene[4,5-d]imidazole-Based Derivatives with Hybridized Local and Charge-Transfer State for Highly Efficient Blue and White Organic Light-Emitting Diodes with Low Efficiency Roll-Off

Liu

Bai

et al. 2020

ACS Appl. Mater. Interfaces

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A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC, and PyPAC, with different excited states are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge-transfer (HLCT) state, endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L’Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50,046 cd m–2 located in the blue region with CIE coordinates of (0.15, 0.21) and an EQE of 6.74% even when the luminance reached over 10,000 cd m–2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of a blue emitter of PyPPA with an HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency, and current efficiency of up to 21.19%, 61.46 lm W–1, and 62.13 cd A–1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.

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Design and performance study of high efficiency/low efficiency roll-off/high CRI hybrid WOLEDs based on aggregation-induced emission materials as fluorescent emitters

Abstract: AIEgens TPB-AC and CP-BP-PXZ are used as non-doped blue and green layers, and Ir(dmppr-mp)2(divm) doped TCTA is used as red layer to construct high-performance hybrid WOLEDs.

Cited by 19 publications

References 32 publications

Rational Design of Ir(III) Phosphors to Strategically Manage Charge Recombination for High-Performance White Organic Light-Emitting Diodes

Rational Design of Ir(III) Phosphors to Strategically Manage Charge Recombination for High-Performance White Organic Light-Emitting Diodes

All‐Fluorescence White Organic Light‐Emitting Diodes Exceeding 20% EQEs by Rational Manipulation of Singlet and Triplet Excitons

Pyrene[4,5-d]imidazole-Based Derivatives with Hybridized Local and Charge-Transfer State for Highly Efficient Blue and White Organic Light-Emitting Diodes with Low Efficiency Roll-Off

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