Unraveling the Turn-On Limitation of Quantum-Dot Electroluminescence via a Stepwise-Increasing Voltage Measurement

Zhu, Xiaoxiang; Wang, Yuechao; Ji, Wenyu

doi:10.1103/physrevapplied.19.024010

Cited by 5 publications

(2 citation statements)

References 48 publications

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“…[26,34] The difference in hole mobility might lead to a higher leakage current density for TCTA devices in low-voltage regions. In addition, it has been reported that TCTA films contain more hole traps than the BCBP layer, [40] which should be another origin for the leakage current. The peak current efficiency (CE) of the BCBP-device (6.0 cd A −1 ) is significantly higher than that of the TCTA-device (3.7 cd A −1 ), as shown in Figure 1d.…”

Section: Resultsmentioning

confidence: 99%

Multinary Cu─In─Zn─S‐based Quantum‐Dot Electroluminescence and Implications on Device Designs

Zheng,

Wang,

Bai

et al. 2023

Laser & Photonics Reviews

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Currently, the performance of quantum‐dot light‐emitting diodes (QLEDs) based on environmental‐friendly Cu─In─Zn─S quantum dots (QDs) still lags far behind that of Cd‐QDs‐based devices. Here it is demonstrated that the unique trap‐related recombination in Cu─In─Zn─S QDs is mainly responsible for the low device efficiency. The luminous efficiency of Cu─In─Zn─S‐based QLEDs is rather sensitive to the temperature and hole‐transporting layers (HTLs) due to the susceptible thermal‐related trappingdetrapping processes of holes in radiative Cu‐related traps. The holes in Cu‐related traps can be quenched by escaping to the valence band of the QDs or/and transferring to the adjacent HTLs. An HTL with low highest occupied molecular orbitals is desired to enhance the hole injection and hinder the aforementioned hole transfer. As a result, a high device efficiency of 6.0 cd A−1 is achieved at room temperature, which is attributed to suppressed HTL‐induced emission quenching and efficient valence‐band‐dominated hole injection from HTL to the QDs. The device efficiency is further increased to 13.2 cd A−1 at 150K by suppressing thermal‐induced quenching.

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Section: Resultsmentioning

confidence: 99%

Multinary Cu─In─Zn─S‐based Quantum‐Dot Electroluminescence and Implications on Device Designs

Zheng,

Wang,

Bai

et al. 2023

Laser & Photonics Reviews

Self Cite

View full text Add to dashboard Cite

show abstract

“…The suppression of charge-loss channels mitigates the charge consumption, hence leading to slow capacitance declining. To explore the dynamics of the holes stored in the nonstoichiometric WO x layers, the transient current of QLEDs is measured by a Multichannel data acquisition card (National Instruments PCIe-6321) . The amplitude of the driving voltage pulse for the transient current measurements is 8.0 V. As shown in Figure e, at first glance, the three devices exhibit typical and similar current properties, consisting of an initial resistance–capacitance (RC) charging current and steady-state current, followed by a discharging process.…”

mentioning

confidence: 99%

Memory-Enabled Quantum-Dot Light-Emitting Diodes

Meng,

Bai,

Zhou

et al. 2024

J. Phys. Chem. Lett.

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Quantum-dot light-emitting diodes (QLEDs) with memory capability can provide multifunctional integration properties in on-chip and intelligent electronic applications. Herein, memory properties are achieved by inserting a tungsten oxide (WO x ) film between the ZnO electron-transporting layer and cathode. Pentavalent tungsten ions (W 5+ ) in this nonstoichiometric WO x film can be oxidized to W 6+ by storing holes, inducing significant electrons in the adjacent ZnO layer. Hole storage in the WO x layer suppresses electron injection into the quantum dot emissive layer, hence reducing electroluminescence intensity on the onset stage of the QLEDs. This operation-history correlation for the electroluminescence intensity means a memory behavior for the QLEDs. Furthermore, the power efficiency of the devices is greatly improved after inserting the WO x layer due to electrical field-dependent selfadaptive electron injection into the quantum dots (QDs). We anticipate this type of QLEDs have potential applications in on-chip integration applications, such as the optical computing field and storage.

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The fatigue effects in red emissive CdSe based QLED operated around turn-on voltage

Zhang

Bao

Chen

et al. 2023

The Journal of Chemical Physics

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The operational stability is a current bottleneck facing the quantum dot light-emitting diodes (QLEDs). In particular, the device working around turn-on voltage suffers from unbalanced charge injection and heavy power loss. Here, we investigate the operational stability of red emissive CdSe QLEDs operated at different applied voltages. Compared to the rising luminance at higher voltages, the device luminance quickly decreases when loaded around the turn-on voltage, but recovers after unloading or slight heat treatment, which is termed fatigue effects of operational QLED. The electroluminescence and photoluminescence spectra before and after a period of operation at low voltages show that the abrupt decrease in device luminance derives from the reduction of quantum yield in quantum dots. Combined with transient photoluminescence and electroluminescence measurements, as well as equivalent circuit model analysis, the electron accumulation in quantum dots mainly accounts for the observed fatigue effects of a QLED during the operation around turn-on voltage. The underlying mechanisms at the low-voltage working regime will be very helpful for the industrialization of QLED.

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Unraveling the Turn-On Limitation of Quantum-Dot Electroluminescence via a Stepwise-Increasing Voltage Measurement

Cited by 5 publications

References 48 publications

Multinary Cu─In─Zn─S‐based Quantum‐Dot Electroluminescence and Implications on Device Designs

Multinary Cu─In─Zn─S‐based Quantum‐Dot Electroluminescence and Implications on Device Designs

Memory-Enabled Quantum-Dot Light-Emitting Diodes

The fatigue effects in red emissive CdSe based QLED operated around turn-on voltage

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