Bright White‐Light Emitting Manganese and Copper Co‐Doped ZnSe Quantum Dots

Panda, Subhendu K.; Hickey, Stephen G.; Demir, Hilmi Volkan; Eychmüller, Alexander

doi:10.1002/anie.201100464

Cited by 176 publications

(138 citation statements)

References 34 publications

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…22,38,39 The above observations are in concordance with the literature, where introduction of electron withdrawing groups in phenoxide and the pyridyl ring of AlQ 3 complexes cause blue shifts and red shifts, respectively, in their emission maximum, while the reverse case was observed in the case of electron donating groups. 42,43 It is well-known that the surface metal ions (here Zn 2+ and Mn 2+ ) and anions (S 2− )bonded to the Qdot via dangling bondsare prone to binding to an external ligand. Among the two metal ions on the surface of Qdots, Zn 2+ may bind to HQ preferentially over Mn 2+ to form QDCs according to Irving− Williams series.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Double Channel Emission from a Redox Active Single Component Quantum Dot Complex

et al. 2014

View full text Add to dashboard Cite

Herein we report the generation and control of double channel emission from a single component system following a facile complexation reaction between a Mn(2+) doped ZnS colloidal quantum dot (Qdot) and an organic ligand (8-hydroxy quinoline; HQ). The double channel emission of the complexed quantum dot-called the quantum dot complex (QDC)-originates from two independent pathways: one from the complex (ZnQ2) formed on the surface of the Qdot and the other from the dopant Mn(2+) ions of the Qdot. Importantly, reaction of ZnQ2·2H2O with the Qdot resulted in the same QDC formation. The emission at 500 nm with an excitation maximum at 364 nm is assigned to the surface complex involving ZnQ2 and a dangling sulfide bond. On the other hand, the emission at 588 nm-with an excitation maximum at 330 nm-which is redox tunable, is ascribed to Mn(2+) dopant. The ZnQ2 complex while present in QDC has superior thermal stability in comparison to the bare complex. Interestingly, while the emission of Mn(2+) was quenched by an electron quencher (benzoquinone), that due to the surface complex remained unaffected. Further, excitation wavelength dependent tunability in chromaticity color coordinates makes the QDC a potential candidate for fabricating a light emitting device of desired color output.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Double Channel Emission from a Redox Active Single Component Quantum Dot Complex

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The doped NCs not only retain nearly all the advantages of intrinsic properties of NCs, but also possess new properties, such as enhanced thermal stability, reduced chemical sensitivity, and elimination of luminescent self-quenching and re-absorption. Accordingly, WLEDs have been reported by combining commercial blue LEDs with those doped NCs [69][70][71][72][73][74]. For example, WLEDs with CRI of 50-60 have been reported by combining single-phase Mn-doped ZnSe NCs [74].…”

Section: Introductionmentioning

confidence: 98%

“…For example, WLEDs with CRI of 50-60 have been reported by combining single-phase Mn-doped ZnSe NCs [74]. Subsequently, the dual-emissive Mn and Cu co-doped ZnS (e) have been successfully used as color converters in fabrication of WLED [72]. However, these Mn and/or Cu doped II-VI NCs have a wide band gap (ZnSe: 2.78 eV; ZnS: 3.6 eV), which could not be excited effectively by commercial blue LEDs to achieve white light.…”

Section: Introductionmentioning

confidence: 98%

Large-scale synthesis of single-source, thermally stable, and dual-emissive Mn-doped Zn–Cu–In–S nanocrystals for bright white light-emitting diodes

Peng

Zhang

et al. 2015

Nano Res.

View full text Add to dashboard Cite

Non-cadmium" dual emissive QDs have been directly synthesized using a one-pot hot-injection technique. A white LED was successfully fabricated using a commercial blue-LED chip combined with the optimal QDs. ABSTRACTThe global demand for resource sustainability is growing. Thus, the development of single-source environment-friendly colloidal semiconductor nanocrystal (NC) phosphors with broadband emission is highly desirable for use as color converters in white light-emitting diodes (WLEDs). We report herein the gram-scale synthesis of single-source, cadmium-free, dual-emissive Mn-doped Zn-Cu-In-S NCs (d-dots) by a simple, non-injection, and low-cost approach in one-pot fashion. This synthesis approach led to the formation of NCs with continuously varying compositions in a radial direction because the reactivity of precursors totally differed among these precursors. Consequently, d-dots exhibited two emission bands, one of which was due to Mn-related emissions and the other was due to the band edge of Zn-Cu-In-S NCs. Emission peaks assigned to band edge were tunable by simple control of particle size and composition. The prepared d-dots also exhibited the characteristic zero self-absorption, a quantum yield of 46%, and good thermal stability. A combination of a commercial blue LED chip with optimal d-dots as color converters gave a high color rending index of up to 90, Commission International de l'Eclairage color coordinates of (0.332, 0.321), and correlated color temperature of 5680 K. These results suggested that this cadmium-free, excellent thermally stable single-phase d-dot phosphor had potential applications in WLEDs. Nano Research DOI () Research Article| www.editorialmanager.com/nare/default.asp 2 Nano Res.

show abstract

“…

…”

mentioning

confidence: 99%

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Adam

Wang

Dubavik

et al. 2015

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

2638www.MaterialsViews.com wileyonlinelibrary.com approaches, [ 15,16 ] effi ciency, [ 17,18 ] extending their spectral range [19][20][21] and environmental friendliness using less toxic materials [22][23][24] sparked industrial applications. Those started with the demonstration of a 40 in. display prototype presented by Samsung [ 25 ] and followed by the foundation of QD Vision, Inc., [ 26 ] whose QDs are now used in the latest series of Sony products. All of the mentioned applications require long-term stability of the QDs under various conditions including high temperatures as well as high intensity illumination. Packaging of the QDs within polymer or inorganic matrices is one way to address these issues, while improving the processability of the QDs at the same time. Commonly used polymers, such as polystyrene and poly(methylmethacrylate) [ 27 ] are relatively less stable and tight in comparison to their inorganic counterparts. Inorganic matrices on the other hand can incorporate the QDs directly from their melt, e.g., using the Czochralski approach, [ 28 ] coated as a thin fi lm directly on their surface [ 29,30 ] or, as recently developed by our group, grown as mixed crystals at ambient temperatures from a saturated salt solution. [ 31 ] Using this method, different types of QDs can be incorporated due to the low thermal stress and, by choosing the proper matrix-QD system, the photoluminescence quantum yields (PL-QYs) are enhanced upon incorporation. [ 32,33 ] Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid-liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid-liquid diffusion-assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil-based ligandexchanged QDs into salt matrices. Furthermore, in a modifi ed two-step approach, the seed-mediated LLDC provides the ability to incorporate oilbased QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof-of-concept white light emitting diode with LLDC-based mixed QD-salt fi lms as an excellent color-conversion layer is demonstrated. These fi ndings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD-salts.

show abstract

Bright White‐Light Emitting Manganese and Copper Co‐Doped ZnSe Quantum Dots

Cited by 176 publications

References 34 publications

Double Channel Emission from a Redox Active Single Component Quantum Dot Complex

Double Channel Emission from a Redox Active Single Component Quantum Dot Complex

Large-scale synthesis of single-source, thermally stable, and dual-emissive Mn-doped Zn–Cu–In–S nanocrystals for bright white light-emitting diodes

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Contact Info

Product

Resources

About