Characterization of Gold-Sputtered Zinc Oxide Nanorods—a Potential Hybrid Material

Perumal, Veeradasan; Hashim, U.; Gopinath, Subash C. B.; Prasad, Haarindraprasad Rajintra; Liu, Weiwen; Balakrishnan, Sharma Rao; Vijayakumar, T. P.; Ruslinda, A. Rahim

doi:10.1186/s11671-016-1245-8

Cited by 34 publications

(10 citation statements)

References 62 publications

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“…Recently, however, it has been established that this optical limitation on the light extraction efficiency can be overcome by using a nanostructured gold thin-film surface coating, which has been found to significantly enhance that ZnO NBE emission output. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Increase in the ZnO NBE luminescence intensity due to Au nanoparticle (NP) surface coatings have been attributed to the formation of an additional fast relaxation channel due to dipole-dipole coupling between excitons and NP plasmon modes, which increases the spontaneous emission rate (SER). [29][30][31] However, this mechanism is unlikely to be an efficient process for gold/ZnO systems because of the large energy difference between the ZnO exciton UV NBE emission at around 3.37 eV and the Au NP longitudinal surface plasmon (LSP) resonance ~ 2.5 eV.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, two different alternate models have been proposed both involving a deep level at ~ 2.5 eV below the ZnO conduction band (CB) and the charge transfer (CT) of hot electrons between ZnO and Au NPs as illustrated in Fig 1. 10,15,25,26 In the first model, a strong green luminescence (GL) generated from the ZnO by native surface defects is resonantly absorbed by the Au NPs. Following excitation, the LSPs then decay into hot carriers, in particular, hot electrons than transfer from high energy Au electronic levels into energetic ZnO CB states, which thermalize to the band edge.…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of the UV emission from gold/ZnO nanorods exhibiting no green luminescence

Fiedler¹,

Lem²,

Hoffmann³

et al. 2020

Opt. Mater. Express

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Large reflection losses at interfaces in light emitting semiconductor devices cause a significant reduction in their light emission and energy efficiencies. Metal nanoparticle (NP) surface coatings have been demonstrated to increase the light extraction efficiency from planar high refractive index semiconductor surfaces. This emission enhancement in Au NP-coated ZnO is widely attributed to involvement of a green (~ 2.5 eV) deep level ZnO defect exciting localized surface plasmons in the NPs that non-radiatively decay into hot electrons, which return to ZnO and radiatively recombine. In this work, we achieve a 6 times enhancement of the ultra-violet excitonic emission in ZnO nanorods that are coated with 5 nm Au NPs without the aid of ZnO defects. Cathodoluminescence (CL), photoluminescence (PL) and a novel concurrent CL-PL technique as well as time resolved PL spectroscopy revealed that the increase in UV emission is due to the formation of an additional fast excitonic relaxation pathway that increases the exciton spontaneous emission rate. Concurrent CL-PL measurements ruled out the presence of charge transfer mechanism in the emission enhancement process. While time resolved PL results confirmed the existence of a new excitonic recombination channel that is attributed to exciton relaxation via the plasmon-assisted excitation of rapid non-radiative Au interband transitions. Our results establish that ZnO defect levels ~ 2.5 eV are not required to facilitate Au NP induced enhancement of the ZnO UV emission.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhancement of the UV emission from gold/ZnO nanorods exhibiting no green luminescence

Fiedler¹,

Lem²,

Hoffmann³

et al. 2020

Opt. Mater. Express

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“…Adsorption of oxygen atoms at the ZnO surface during processes such as annealing creates a current/flow of electrons from the ZnO matrix towards the O 2 atoms, causing the ZnO layers to harbor greater resistance. These O 2 -entrapped electrons induce spatial charge formations which create local electric fields that further impede film conductivity [35]. The larger surface area of the grown ZnO nanorods paired with their significantly higher grain size boundary causes even greater resistance since it leads to an increased amount of surface adsorbed O 2 atoms and subsequent greater restriction in the movement of spatially trapped conduction band electrons.…”

Section: Analysis Of Flt3 Mutations Through Electrochemical Impedance...mentioning

confidence: 99%

Reverse Electrochemical Sensing of FLT3-ITD Mutations in Acute Myeloid Leukemia Using Gold Sputtered ZnO-Nanorod Configured DNA Biosensors

et al. 2022

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Detection of genetic mutations leading to hematological malignancies is a key factor in the early diagnosis of acute myeloid leukemia (AML). FLT3-ITD mutations are an alarming gene defect found commonly in AML patients associated with high cases of leukemia and low survival rates. Available diagnostic assessments for FLT3-ITD are incapable of combining cost-effective detection platforms with high analytical performances. To circumvent this, we developed an efficient DNA biosensor for the recognition of AML caused by FLT3-ITD mutation utilizing electrochemical impedance characterization. The system was designed by adhering gold-sputtered zinc oxide (ZnO) nanorods onto interdigitated electrode (IDE) sensor chips. The sensing surface was biointerfaced with capture probes designed to hybridize with unmutated FLT3 sequences instead of the mutated FLT3-ITD gene, establishing a reverse manner of target detection. The developed biosensor demonstrated specific detection of mutated FLT3 genes, with high levels of sensitivity in response to analyte concentrations as low as 1 nM. The sensor also exhibited a stable functional life span of more than five weeks with good reproducibility and high discriminatory properties against FLT3 gene targets. Hence, the developed sensor is a promising tool for rapid and low-cost diagnostic applications relevant to the clinical prognosis of AML stemming from FLT3-ITD mutations.

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Section: In‐depth Probing Of Hybrid Metal–semiconductor Nanocrystalsmentioning

confidence: 99%

“…nanorods decorated with varying diameter of Au NPs can be differentiated using XRD pattern depicted in Figure 8b. [150] Diffraction peak corresponding to Au (111) and (200) gets intensify as Au NP size increases from 10 to 40 nm. There are numerous reports which investigated the impact of different MNPs concentration over crystallite size, d-spacing, and dislocation density using XRD.…”

Section: Probing Crystal Structure Of Metal-semiconductor Hybridsmentioning

confidence: 99%

Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

Kumar

Nisika

Kumar

2020

Advanced Optical Materials

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years, great advances have been made to grow various shaped semiconductor nanocrystals (SNCs) like quantum dots, [7] nanowires, [8] nanorods (NR), [9] and other advanced shaped nanostructures, [10-12] with great precision. However, these semiconductor nanostructures have small extinction cross-sections (even smaller than geometric cross-section), leading to limited absorbance and emission quantum yields. This hinders the progress of semiconductor nanostructures in several areas ranging from clean energy production to various sensing applications. Among many promising solutions, integrating plasmonic nanoparticles (PNPs) with semiconductor nanostructures emerges as the most prominent way to alleviate aforementioned issue. The PNPs have greater extinction cross-section than SNCs (even greater than geometric cross-section), owing to light absorption and scattering by collective and coherent electron oscillations. [13,14] Moreover, these coherent oscillations can couple with electromagnetic wavelengths far greater than particle size, enabling them to guide light to subwavelength scales, thus overcoming diffraction limit. [15] Besides this, proper control over size and shape of plasmonic nanostructures enables engineering of their intrinsic properties to meet the criteria of required application. [16] For instance, by changing the aspect ratio (length to diameter ratio) of nanorods, one can cover wide spectral regions ranging from visible to near-infrared (NIR) regimes. [17] Thus, the integration of plasmonic and semiconductor nanostructures to obtain greater extinction cross-sections and modified properties in these hybrid nanostructures has received great attention from the research community over the past years. The properties of these hybrid nanostructures can be very different from the two nanoconstituents (metal and semiconductor nanostructures), owing to plasmon-exciton interactions. [18-20] Various configurations of metal/semiconductor nanostructures have been synthesized like metallic core/semiconductor shell, [21] semiconductor NR/metal nanoparticles (MNPs), [22] Janus metal/ semiconductor nanostructures, [23] and many others have been reported, [24-26] with varying absorption and emissive properties, targeting high performance applications. The energy transfer between metal-semiconductor nanostructures resulting from integration of PNPs and SNCs Hybrid nanostructures composed of metal and semiconducting nanocrystals have drawn tremendous attention owing to their extraordinary absorption and emission properties. The energy transfer in metal-semiconductor hybrids as a result of synergetic plasmon-exciton interactions leads to numerous applications in the field of solar energy harvesting, photocatalytic reactions, imaging, photonics, sensing, and many more. Various breakthroughs in advanced characterization techniques over the past decade have disclosed several factors affecting the energy transfer processes leading to modified absorption and emission properties in metal-semiconductor hybrids. Herein, various ...

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Characterization of Gold-Sputtered Zinc Oxide Nanorods—a Potential Hybrid Material

Cited by 34 publications

References 62 publications

Enhancement of the UV emission from gold/ZnO nanorods exhibiting no green luminescence

Enhancement of the UV emission from gold/ZnO nanorods exhibiting no green luminescence

Reverse Electrochemical Sensing of FLT3-ITD Mutations in Acute Myeloid Leukemia Using Gold Sputtered ZnO-Nanorod Configured DNA Biosensors

Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

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