Green, yellow, and orange defect emission from ZnO nanostructures: Influence of excitation wavelength

Djurišić, Aleksandra B.; Leung, Yu Hang; Tam, K. H.; Liu, Ding; Ge, Weikun; Chen, H. Y.; Gwo, Shangjr

doi:10.1063/1.2182096

Cited by 538 publications

(286 citation statements)

References 24 publications

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“…16 for optical transmission and emission images). According to the literature 33 , the broad emission band at around 450-800 nm originates from defect-mediated charge recombination on the ZnO surface. The intensity-weighted average lifetime (/t PL S) for ZnO was 27 ns (/t PL S ¼ 25B30 ns for five different mesocrystals) (Supplementary Table 3).…”

Section: Resultsmentioning

confidence: 99%

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

et al. 2014

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The alignment of nanoparticle building blocks into ordered superstructures is one of the key topics in modern colloid and material chemistry. Metal oxide mesocrystals are superstructures of assembled nanoparticles of metal oxides and have potentially tunable electronic, optical and magnetic properties, which would be useful for applications ranging from catalysis to optoelectronics. Here we report a facile and general approach for synthesizing metal oxide mesocrystals and developing them into new nanocomposite materials containing two different metals. The surface and internal structures of the mesocrystals were fully characterized by electron microscopy techniques. Single-particle confocal fluorescence spectroscopy, electron paramagnetic resonance spectroscopy and time-resolved diffuse reflectance spectroscopy measurements revealed that efficient charge transfer occurred between n-type and p-type semiconductor nanoparticles in the composite mesocrystals. This behaviour is desirable for their applications ranging from catalysis, optoelectronics and sensing, to energy storage and conversion.

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Section: Resultsmentioning

confidence: 99%

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

et al. 2014

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“…In its most common form, the hexagonal wurtzite structure of ZnO has two different surfaces; one is the polar plane and includes respectively [61]. ZnO does not only emit in the UV region, it also emits covering the whole visible spectra which emits green, yellow and in the red region [62][63][64]. The UV spectrum is associated with near band-edge transition in ZnO, namely, the recombination of the free excitons.…”

Section: Zinc Oxide (Zno)mentioning

confidence: 99%

Synthesising Metal Oxide Materials and Their Composite Nanostructures for Sensing and Optoelectronic Device Applications

Khun¹

2015

Linköping Studies in Science and Technology. Dissertations

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Research on nanomaterials has been revolutionized in the last few years because of the attractive properties they have in comparison to the bulk phase of similar materials. These properties are physical, chemical, catalytic and optical. Among these nanomaterials, the metal oxide nanostructures have become of particular interest to scientists for the development of different optical, biochemical and biomedical nanodevices. In the present research work using the advantageous features of nanotechnology, high performance nanodevices for optoelectronics with a wide band gap compound nanostructure and highly sensitive sensor devices have been demonstrated. The nanotechnology is used to fabricate sensitive and precise nanodevices based on nanomaterials for the application of sensing.Among metal oxide nanostructures, ZnO, CuO and NiO are attractive materials because of their unique properties; their high surface area to volume ratio, their energy band gap of 3.37 eV, 1.2 eV and 3.7 eV, respectively, biocompatibility, high electron mobility, fast electron transfer rate and they are environmental-friendly in many applications. When used in sensor devices, nanomaterials have indicated high selectivity for possible use to detect the various analytes even in small volumes. Metal oxide nanostructures have shown to be good for optoelectronic nanodevices because of their electrical characteristics, high optical absorption and low-processing temperature.In this thesis, the synthesis of different morphologies of metal oxide semiconductor nanostructures and their composite using the hydrothermal method are demonstrated for various applications. This thesis is divided into three parts:In the first part of this research work, the fabrication of well-aligned ZnO nanorods using different concentrations of composite seed layer of inorganic and organic materials when using the hydrothermal growth method is presented. The effect of the composite seed layer on the i Abstract alignment, density and optical properties of the grown ZnO nanorods is investigated (paper I).Utilizing the advantage of ZnO nanostructure, a comparative study of ZnO nanorods and thin films for chemical and biosensing application was carried out. The ZnO nanorods and thin films were functionalized with strontium ionophore membrane, immobilized the galactose oxidase and lactate oxidase for determining the strontium ions, D-galactose and L-lactic acid, respectively (paper II).In the second part, the effects of different urea concentrations on the morphology of CuO nanostructures is studied as described in paper III. Moreover, CuO nanoflowers were functionalized with cadmium ion ionophore for the detection of Cd ions, while CuO nanosheets were grown by the low temperature growth method and were used for the development of a nonenzymatic glucose sensor, respectively (Paper IV).In the last part of this thesis, composite nanostructures of CuO/ZnO and NiO/ZnO were applied to develop dopamine sensor and fast sensitive UV photodetector, respectively. A nanohybrid of C...

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“…It is quite obvious that the observed changes are due to complicated defect chemistry relevant to the sonochemical processing. As reported in the literature [1,10,[27][28][29], room-temperature PL of ZnO can exhibit one emission peak in the UV region which is due to the recombination of free excitons, and one or more peaks in the visible region. The latter ones are commonly associated with the defectrelated emissions, such that the defect properties strongly affect optical spectra of ZnO.…”

Section: Pl Spectramentioning

confidence: 83%

“…Decomposed band parameters and peak attribution for the PL spectra given in Fig. 1 [10,31] this scenario into account, it can be expected that the concentration of oxygen vacancies in SC samples will vary with varying stirring time which, in turn, can be taken into account, when analyzing the PL spectral changes given in Fig. 1.…”

Section: Ft-ir Spectramentioning

confidence: 99%

“…For example, high thermal and chemical stability, simple tunability of the optical and electrical properties are widely applicable in optoelectronic devices [6,7]. Moreover, while exhibiting an excitonic emission peak in the ultraviolet (UV) region, ZnO typically shows strong visible luminescence bands which are due to numerous point defects present in the lattice [8][9][10][11]. Due to these facts, various methods of producing zinc oxide with different morphology and point defect content have been developed so far [12].…”

Section: Introductionmentioning

confidence: 99%

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Carrier recombination in sonochemically synthesized ZnO powders

Zakirov

Korotchenkov

2017

Materials Science-Poland

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ZnO powders with particle size in the nm to µm range have been fabricated by sonochemical method, utilizing zinc acetate and sodium hydroxide as starting materials. Carrier recombination processes in the powders have been investigated using the photoluminescence, FT-IR and surface photovoltage techniques. It has been shown that the photoluminescence spectra exhibit a number of defect-related emission bands which are typically observed in ZnO lattice and which depend on the sonication time. It has been found that the increase of the stirring time results in a faster decay of the photovoltage transients for times shorter than approximately 5 ms. From the obtained data it has been concluded that the sonication modifies the complicated trapping dynamics from volume to surface defects, whereas the fabrication method itself offers a remarkably convenient means of modifying the relative content of the surface-to-volume defect ratio in powder grains and altering the dynamics of photoexcited carriers.

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Green, yellow, and orange defect emission from ZnO nanostructures: Influence of excitation wavelength

Cited by 538 publications

References 24 publications

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

Synthesising Metal Oxide Materials and Their Composite Nanostructures for Sensing and Optoelectronic Device Applications

Carrier recombination in sonochemically synthesized ZnO powders

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