Phosphine-free synthesis of Zn1−xCdxSe/ZnSe/ZnSexS1−x/ZnS core/multishell structures with bright and stable blue–green photoluminescence

Shen, Huaibin; Zhou, Changhua; Xu, Shasha; Yu, Cailan; Wang, Hongzhe; Chen, Xia; Li, Lin Song

doi:10.1039/c0jm03605f

Cited by 52 publications

(44 citation statements)

References 41 publications

(49 reference statements)

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“…PL spectra shift to longer wavelengths compared to that of the original cores in the first 15 min of the reaction (from 445 to 449 nm). Such red shift has also been observed in several other multishell QDs and indicates the extension of wave function into the shell region, which increases the effective size of the core and reduces the quantum confinement effect by the semiconductor wave function . It also reveals that the absorption and PL spectra show slight blue shift from 15 min to the end of the reaction (from 449 to 441 nm).…”

Section: Resultssupporting

confidence: 56%

“…In the past, most of the synthesis of QDs with violet‐blue emission is mainly focused on CdS based core/shell QDs and their QYs were lower than 65% . Even though, there are a few studies based on CdSe or ZnCdSe core/shell QDs, and the QYs of these reports were still less than 75%. The researches on CdSe related QDs with violet‐blue emission is yet not optimistic.…”

Section: Introductionmentioning

confidence: 99%

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High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots

Shen

Bai

Wang

et al. 2013

Adv Funct Materials

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154

121

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High‐quality violet‐blue emitting ZnxCd1‐xS/ZnS core/shell quantum dots (QDs) are synthesized by a new method, called “nucleation at low temperature/shell growth at high temperature”. The resulting nearly monodisperse ZnxCd1‐xS/ZnS core/shell QDs have high PL quantum yield (near to 100%), high color purity (FWHM) <25 nm), good color tunability in the violet‐blue optical window from 400 to 470 nm, and good chemical/photochemical stability. More importantly, the new well‐established protocols are easy to apply to large‐scale synthesis; around 37 g ZnxCd1‐xS/ZnS core/shell QDs can be easily synthesized in one batch reaction. Highly efficient deep‐blue quantum dot‐based light‐emitting diodes (QD‐LEDs) are demonstrated by employing the ZnxCd1‐xS/ZnS core/shell QDs as emitters. The bright and efficient QD‐LEDs show a maximum luminance up to 4100 cd m−2, and peak external quantum efficiency (EQE) of 3.8%, corresponding to 1.13 cd A−1 in luminous efficiency. Such high value of the peak EQE can be comparable with OLED technology. These results signify a remarkable progress, not only in the synthesis of high‐quality QDs but also in QD‐LEDs that offer a practicle platform for the realization of QD‐based violet‐blue display and lighting.

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Section: Resultssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots

Shen

Bai

Wang

et al. 2013

Adv Funct Materials

Self Cite

154

121

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“…One of the fundamental questions guiding research is how to obtain QY ≈100% QDs for QLED applications . In our previous studies, a structure with alloyed Zn 1− x Cd x Se QDs and ZnSe, ZnS shells as ideal high photoluminescent quantum yield (PLQY) (between 40% and 75%) red emitter has been designed and synthesized via facile “phosphine‐free” wet chemical method . Most recently, we have further developed a “low‐temperature nucleation and high‐temperature shell growth” method by which stable QDs with even higher QY can be obtained .…”

Section: Resultsmentioning

confidence: 99%

Over 30% External Quantum Efficiency Light‐Emitting Diodes by Engineering Quantum Dot‐Assisted Energy Level Match for Hole Transport Layer

Song

Ouyang

Shen

et al. 2019

Adv Funct Materials

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252

237

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In the study of hybrid quantum dot light-emitting diodes (QLEDs), even for state-of-the-art achievement, there still exists a long-standing charge balance problem, i.e., sufficient electron injection versus inefficient hole injection due to the large valence band offset of quantum dots (QDs) with respect to the adjacent carrier transport layer. Here the dedicated design and synthesis of high luminescence Zn 1−x Cd x Se/ZnSe/ZnS QDs is reported by precisely controlled shell growth, which have matched energy level with the adjacent hole transport layer in QLEDs. As emitters, such Zn 1−x Cd x Se-based QLEDs exhibit peak external quantum efficiencies (EQE) of up to 30.9%, maximum brightness of over 334 000 cd m −2 , very low efficiency roll-off at high current density (EQE ≈25% @ current density of 150 mA cm −2 ), and operational lifetime extended to ≈1 800 000 h at 100 cd m −2 . These extraordinary performances make this work the best among all solution-processed QLEDs reported in literature so far by achieving simultaneously high luminescence and balanced charge injection. These major advances are attributed to the combination of an intermediate ZnSe layer with an ultrathin ZnS outer layer as the shell materials and surface modification with 2-ethylhexane-1-thiol, which can dramatically improve hole injection efficiency and thus lead to more balanced charge injection.

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“…The PMAH have hydrophobic chains available for anchoring the hydrophobic CdSe/ZnS QDs and free carboxylic acid groups available for further surface modification. The hydrophobic QDs and PMAH bound to each other via the phase-transfer stem to form PMAH-stabilized PL QDs (Liu et al 2013;Shen et al 2011a;Shen et al 2011c;Zhou et al 2010). Briefly, 5.78g of PMAH (0.32 mmol) was dissolved in 20 mL of chloroform.…”

Section: Introductionmentioning

confidence: 99%

Multiplexed detection of influenza A virus subtype H5 and H9 via quantum dot-based immunoassay

Yuan

Zhou

et al. 2016

Biosensors and Bioelectronics

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A quantum dot-based lateral flow immunoassay system (QD-LFIAS) was developed to simultaneously detect both influenza A virus subtypes H5 and H9. Water-soluble carboxyl-functionalized quantum dots (QDs) were used as fluorescent tags. The QDs were conjugated to specific influenza A virus subtype H5 and H9 antibodies via an amide bond. When influenza A virus subtype H5 or H9 was added to the QD-LFIAS, the QD-labeled antibodies specifically bound to the H5 or H9 subtype viruses and were then captured by the coating antibodies at test line 1 or 2 to form a sandwich complex. This complex produced a bright fluorescent band in response to 365 nm ultraviolet excitation. The intensity of fluorescence can be detected using an inexpensive, low-maintenance instrument, and the virus concentration directly correlates with the fluorescence intensity. The detection limit of the QD-LFIAS for influenza A virus subtype H5 was 0.016 HAU, and the detection limit of the QD-LFIAS for influenza A virus subtype H9 was 0.25 HAU. The specificity and reproducibility were good. The simple analysis step and objective results that can be obtained within 15 min indicate that this QD-LFIAS is a highly efficient test that can be used to monitor and prevent both Influenza A virus subtypes H5 and H9.

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Phosphine-free synthesis of Zn1−xCdxSe/ZnSe/ZnSexS1−x/ZnS core/multishell structures with bright and stable blue–green photoluminescence

Cited by 52 publications

References 41 publications

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots

Over 30% External Quantum Efficiency Light‐Emitting Diodes by Engineering Quantum Dot‐Assisted Energy Level Match for Hole Transport Layer

Multiplexed detection of influenza A virus subtype H5 and H9 via quantum dot-based immunoassay

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Phosphine-free synthesis of Zn1−xCdxSe/ZnSe/ZnSexS1−x/ZnS core/multishell structures with bright and stable blue–green photoluminescence

Cited by 52 publications

References 41 publications

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality ZnxCd1‐xS/ZnS Core/Shell Quantum Dots

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality ZnxCd1‐xS/ZnS Core/Shell Quantum Dots

Over 30% External Quantum Efficiency Light‐Emitting Diodes by Engineering Quantum Dot‐Assisted Energy Level Match for Hole Transport Layer

Multiplexed detection of influenza A virus subtype H5 and H9 via quantum dot-based immunoassay

Contact Info

Product

Resources

About

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality Zn_xCd_1‐xS/ZnS Core/Shell Quantum Dots