Tunable white light from photo- and electroluminescence of ZnO nanoparticles

Oliva, J.; Perez-Mayen, Leonardo; Rosa, E. De la; Dı́az-Torres, L.A.; Torres–Castro, Alejandro; Salas, P.

doi:10.1088/0022-3727/47/1/015104

Cited by 14 publications

(6 citation statements)

References 28 publications

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“…The centers responsible for the visible emission are actually so intense that they can be used as single photon emitters 5 6 , making these ZnO QDs an interesting alternative to chalcogenide ones, in particular for bioimaging, due to their reduced toxicity and low cost. This intense visible emission can also be useful to build optoelectronic devices such as white LEDs 7 8 or to enhance the conversion efficiency of electrolytic or p-n junction solar cells through the down-shifting process 9 .…”

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confidence: 99%

Intense visible emission from ZnO/PAAX (X = H or Na) nanocomposite synthesized via a simple and scalable sol-gel method

Zhu

Apostoluk

Gautier

et al. 2016

Sci Rep

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Intense visible nano-emitters are key objects for many technologies such as single photon source, bio-labels or energy convertors. Chalcogenide nanocrystals have ruled this domain for several decades. However, there is a demand for cheaper and less toxic materials. In this scheme, ZnO nanoparticles have appeared as potential candidates. At the nanoscale, they exhibit crystalline defects which can generate intense visible emission. However, even though photoluminescence quantum yields as high as 60% have been reported, it still remains to get quantum yield of that order of magnitude which remains stable over a long period. In this purpose, we present hybrid ZnO/polyacrylic acid (PAAH) nanocomposites, obtained from the hydrolysis of diethylzinc in presence of PAAH, exhibiting quantum yield systematically larger than 20%. By optimizing the nature and properties of the polymeric acid, the quantum yield is increased up to 70% and remains stable over months. This enhancement is explained by a model based on the hybrid type II heterostructure formed by ZnO/PAAH. The addition of PAAX (X = H or Na) during the hydrolysis of ZnEt2 represents a cost effective method to synthesize scalable amounts of highly luminescent ZnO/PAAX nanocomposites.

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confidence: 99%

Intense visible emission from ZnO/PAAX (X = H or Na) nanocomposite synthesized via a simple and scalable sol-gel method

Zhu

Apostoluk

Gautier

et al. 2016

Sci Rep

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“…Examining the individual emission responses of FC and CC (Fig. 5(b)) there is also the possibility that self-absorption may be occurring and it is expected that this may become more apparent at higher concentrations 47,48 . Observations from a complimentary experiment in which the amount of DA was increased 7-fold and added to a fixed CC:FC (1.375:1) ratio, given in (Table S1), show the production of WLE at 390 nm.…”

Section: Resultsmentioning

confidence: 99%

White Light Emission from a Simple Mixture of Fluorescent Organic Compounds

Sarih

Myers

Slater

et al. 2019

Sci Rep

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Three fluorescent organic compounds—furocoumarin (FC), dansyl aniline (DA), and 7-hydroxycoumarin-3-carboxylic acid (CC)—are mixed to produce almost pure white light emission (WLE). This novel mixture is immobilised in silica aerogel and applied as a coating to a UV LED to demonstrate its applicability as a low-cost, organic coating for WLE via simultaneous emission. In ethanol solution and when immobilised in silica aerogel, the mixture exhibits a Commission Internationale d’Eclairage (CIE) chromaticity index of (0.27, 0.33). It was observed that a broadband and simultaneous emission involving coumarin carboxylic acid, furocoumarin and dansyl aniline played a vital role in obtaining a CIE index close to that of pure white light.

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“…A potential application of this defect-induced emission is the development of white light emitting diodes, as suggested by studies in which ZnO nanocrystals (NCs) have been exploited as phosphors to convert UV or blue electroluminescence (EL) into a visible continuum [16,17]. In parallel, direct visible electroluminescence of vacancy and interstitial defects in ZnO has also been demonstrated by many teams [18][19][20][21][22][23][24][25][26]. As is the case for ZnO-based LEDs in the UV, most of these developments have been achieved by pairing an n-doped ZnO region (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…As is the case for ZnO-based LEDs in the UV, most of these developments have been achieved by pairing an n-doped ZnO region (e.g. a polycrystalline or powder-based layer [22], a nanowire array [23][24][25][26], or a dense ensemble of ZnO colloidal NCs [27][28][29]) with a p-doped inorganic or organic layer, although it should be mentioned that ZnO homojunctions have also been demonstrated [21]. In these studies, the turn-on voltage is around 3-5 V and the EL spectra are typically measured at 8-10 V. It is noteworthy that external quantum efficiencies (EQE) are usually not reported although a recent study reports EQE of 4% at 6V [26].…”

Section: Introductionmentioning

confidence: 99%

“…In this context, there is an interest to develop strategies that maximize the defect density and their emissivity. A known avenue to enhance the defect-induced luminescence is to favor nano-composites (ZnO nanocrystals and nanowiresK) over microstructured or bulk ZnO layers due to the higher surface-to-volume ratio [18] and most ZnO-based visible LEDs reported so far employ nanowires or nanocrystals [23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

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Enhancement and tuning of the defect-induced electroluminescence of ZnO mesoporous layers in the visible range

Roland¹,

Schanne²,

Bogicevic³

et al. 2022

Nanotechnology

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We show a way to pattern the visible electroluminescence of solution-processed mesoporous ZnO layers. Our approach consists in locally changing the nanoscale morphology of the coated ZnO layers by patterning the underlying surface with thin metallic patches. Above the metal, the ZnO film is organized in clusters that enhance its defect-induced electroluminescence. The resulting emission occurs over a large continuum of wavelengths in the visible and near-infrared range. This broad emission continuum is filtered by thin-film interferences that develops within the device, making it possible to fabricate LEDs with different colors by adjusting the thickness of their transparent electrode. When the metallic patterns used to change the morphology of the ZnO layer reach sub-micron dimensions, additional plasmonic effects arise, providing extra degrees of freedom to tune the colour and polarization of the emitted photons.

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Tunable white light from photo- and electroluminescence of ZnO nanoparticles

Cited by 14 publications

References 28 publications

Intense visible emission from ZnO/PAAX (X = H or Na) nanocomposite synthesized via a simple and scalable sol-gel method

Intense visible emission from ZnO/PAAX (X = H or Na) nanocomposite synthesized via a simple and scalable sol-gel method

White Light Emission from a Simple Mixture of Fluorescent Organic Compounds

Enhancement and tuning of the defect-induced electroluminescence of ZnO mesoporous layers in the visible range

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