White electroluminescence from a hybrid polymer-GaN:Mg nanocrystals device

Tan, Mingqian; Mahalingam, Venkataramanan; Veggel, Frank C. J. M. van

doi:10.1063/1.2772667

Cited by 6 publications

(8 citation statements)

References 20 publications

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“…The bare SiO 2 nanoparticles have a very weak PL peak at 412 nm (Supporting Information Figure S1) in agreement with the value reported for silica . GaN nanoparticles also show a very weak PL peak at 395 nm, which is probably a band edge emission (Supporting Information Figure S1) in agreement with previous results obtained by our group. − Furthermore, the Eu 3+ ions emission lines were also observed in Eu 3+ -doped Ga 2 O 3 @SiO 2 nanoparticles in between 580 to 650 nm upon excitation with λ exi = 464 nm (i.e., direct excitation of the Eu 3+ ions). After nitridation Eu 2+ -doped Ga N @SiO 2 nanoparticles lacked the presence of any Eu 3+ based emission, which further support the reduction of Eu 3+ ions to Eu 2+ ions (Supporting Information Figure S2).…”

Section: Resultssupporting

confidence: 90%

Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

Gautam

Veggel

2011

Chem. Mater.

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Significant progress in solid state lighting has been achieved since the development of nitride-based blue light-emitting diodes (LEDs) from Nichia chemical industries, 1À5 but reliable and highly efficient blue LEDs are still in high demand especially polymer-based LEDs because of their cheap, flexible, and substrate suitability for daily use. 6À9 Particularly, blue-emitting materials with CIE coordinates nearly X = 0.15 and Y = 0.15 are really important as defined by the Department of Energy (DOE) and Optoelectrical Industry Development association (OIDA). 9 Blue-emitting materials are not only a major constituent for red-green-blue full color displays but also a key emitting element for generating white light. For example, combination of the GaN-based blue LED (λ emi ∼ 465 nm) with the Y 3 Al 5 O 12 : Ce 3+ yellow phosphor (λ emi ∼ 555 nm) gives white light. 4 Blue and UV LEDs also have great prospect in data-storage capacities in compact discs (CDs) and digital video discs (DVDs), because the storage density of compact discs is inversely proportional to the square of the laser wavelength. 2 Despite the application of organic electroluminescent devices in making blue organic lightemitting diodes (OLEDs), their low efficiency and stability still remain a challenge and calls for the use of very robust materials such as GaN. 10À13 GaN has a direct wide band gap (3.4 eV) at room temperature and is a promising host electroluminescence (EL) material for multicolor emitting phosphor. Doping of GaN thin films with Tm 3+ , Er 3+ , and Eu 3+ ions results, upon excitation, in blue, green, and red emission, respectively. 14 Furthermore enhancement in the blue emission intensity was observed on doping Tm 3+ in Al 1 Ga 1-X N instead of GaN thin film. The CIE coordinates were tuned to X = 0.13, Y = 0.09, and the enhanced emission from Tm 3+ ions was proportional to the Al content in the film. 15 Recently, Yang et al. 16 fabricated GaN-based blue LEDs with an EL peak centered at 447 nm. In another report Zhao et al. 17 obtained blue EL by using Au/AlN/p-Si heterostructure and had an EL peak centered at 490 nm. The CIE coordinates are X = 0.25, Y = 0.33, as calculated by us, which show a deviation from the blue region.ZnO based heterostructures were also applied in the fabrication of EL devices. The blue EL emission from n-ZnO/nMg y Zn 1-y O/Zn 1-x Cd x O/P-SiC heterojunction diodes as reported by Nakamura et al. 18 has an EL peak centered at 480 nm. The CIE coordinates, as calculated by us, are X = 0.29, Y = 0.32, which is away from the required blue. Li et al. 6 also fabricated a blue EL device using ZnO based heterojunction diodes in the presence of active layer of CdZnO with an El peak centered at 459 nm. Although the peak centered in the blue, the CIE coordinates, as calculated by us, are X = 0.62, Y = 0.32, again away from blue. Ultraviolet-blue LEDs device fabricated by Guo et al. 19 used ZnO nanowires/polymer/p-GaN in heterojunction structure with the EL emission peaks were at 400 nm. The CIE coordinates, as calculat...

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Section: Resultssupporting

confidence: 90%

Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

Gautam

Veggel

2011

Chem. Mater.

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“…The inset is an enlarged view of the CdSe/ZnS NCs taken by using HRTEM, and the sizes of the CdSe/ZnS NCs which are embedded in a PVK and TPBi organic matrix are approximately 5 nm. Even though previously the microstructure of the NCs embedded in polymer hybrid with a single active layer has been carefully examined through atomic force microscopy and highresolution SEM or TEM, the distribution of NCs in polymer hybrid has not been accurately investigated [9][10][11]15]. From the TEM study, it is revealed that semiconductor CdSe NCs are partially and physically adsorbed on the surface of PVK polymer and TPBi small molecules instead of being embedded inside the polymer or molecules.…”

Section: Resultsmentioning

confidence: 99%

“…organic layers respectively have been investigated as promising memory devices [6]. Furthermore, for the application of NC-based electroluminescence (EL) devices, either singlelayer hybrids of NCs such as CdSe/ZnS, Si/SiO 2 , ZnO, and Cu-doped ZnS dispersed in a polymer matrix [7][8][9][10][11], or multi-layers with a color emitting colloidal NC layer such as CdSe/ZnS or a mixture of CdSe/ZnS (red-green color) and ZnCdS (blue color) in hybrid organic-inorganic structures [3,[12][13][14][15] sandwiched by two electrodes, have been extensively fabricated. Compared to multilayer structure NC LEDs, requiring precise control of deposition conditions or temperature, a single active layer structured one using a hybrid polymer-NC device is more conveniently fabricated in a simple method.…”

Section: Introductionmentioning

confidence: 99%

Electroluminescence of a single active layer polymer–nanocrystal hybrid light-emitting diode with inversion symmetry

Son¹,

Park²,

Choi³

et al. 2009

Nanotechnology

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A hybrid polymer-nanocrystal (NC) light-emitting diode (LED) device with a single active layer structure is simply fabricated by a spin coating. From a high-resolution transmission electron microscopy (HRTEM) study, each PVK polymer particle is observed to be capped with TPBi molecules and CdSe/ZnS NCs are mainly distributed along the circumference of PVK and TPBi surfaces, resulting in a core-shell polymer-NC hybrid of [CdSe/ZnS]/TPBi/[CdSe/ZnS]/PVK. An Al/[CdSe/ZnS]/TPBi/[CdSe/ZnS]/PVK/indium-tin oxide(ITO)/glass LED shows electroluminescence (EL) centered at around 585 nm at the forward bias of +10 V, which clearly reveals that CdSe/ZnS NCs existing at the interface between PVK and TPBi act as recombination centers for excitons. In particular, EL can be observed at both forward bias and reverse bias, and this means that this device with an isotropic distribution of NCs has an inversion symmetry.

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“…Here we report blue photoluminescence from an InN@SiO 2 nanomaterial, from which electroluminescence has recently been reported 19. This material was prepared by following a synthetic strategy recently developed by us to grow semiconductor nanocrystals on silica nanoparticles20 and is part of a larger effort to produce nanomaterials that show blue photo‐ and electroluminescence in polymer‐based light‐emitting diodes 19–22. In fact, this work stimulated us to try other nitrides than GaN.…”

Section: Introductionmentioning

confidence: 88%

InN@SiO₂ Nanomaterials as New Blue Light Emitters

2008

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In this article we report blue photoluminescence (≈ 450 nm) from InN@SiO2 nanomaterials. The InN@SiO2 nanomaterials were prepared by a simple precipitation reaction followed by a solid‐state reaction. Various control experiments demonstrate that the interface between the InN and SiO2 seems to play a crucial role in the origin of the blue emission from the InN@SiO2 nanomaterial. The InN@SiO2 nanomaterial was characterized by using analytical methods such as TEM, XRD, Raman, XPS, and photoluminescence spectroscopy, which confirmed the existence of InN on SiO2 with a small excess of nitrogen relative to indium.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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White electroluminescence from a hybrid polymer-GaN:Mg nanocrystals device

Cited by 6 publications

References 20 publications

Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

Electroluminescence of a single active layer polymer–nanocrystal hybrid light-emitting diode with inversion symmetry

InN@SiO₂ Nanomaterials as New Blue Light Emitters

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White electroluminescence from a hybrid polymer-GaN:Mg nanocrystals device

Cited by 6 publications

References 20 publications

Blue Electroluminescence from Eu2+-Doped GaN@SiO2 Nanostructures Tuned to Industrial Standards

Blue Electroluminescence from Eu2+-Doped GaN@SiO2 Nanostructures Tuned to Industrial Standards

Electroluminescence of a single active layer polymer–nanocrystal hybrid light-emitting diode with inversion symmetry

InN@SiO2 Nanomaterials as New Blue Light Emitters

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Product

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Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

Blue Electroluminescence from Eu²⁺-Doped GaN@SiO₂ Nanostructures Tuned to Industrial Standards

InN@SiO₂ Nanomaterials as New Blue Light Emitters