Broadband enhanced fluorescence using zinc-oxide nanoflower arrays

Wang, Tiesheng; Costan, Jozerd; Centeno, Anthony; Pang, Jiangli; Darvill, Daniel; Ryan, Mary P.; Xie, Fang

doi:10.1039/c4tc02751e

Cited by 31 publications

(33 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…33,40 Using finite difference time domain (FDTD) analysis, our group previously investigated electric field enhancement due to aligned ZnO NR arrays of 70 nm diameter, excited by a normally incident electric field at wavelengths of 530 nm and 650 nm, respectively. 12 The work showed that the electric field enhancement could account for the increase in fluorescence for aligned NR arrays, which was less than 1 order of magnitude. In the same study the fluorescent enhancement due to NFs was also studied under the same conditions and was found to be about 4 times higher than for aligned NRs, once corrected for increased surface area available for fluorophore attachment.…”

Section: Introductionmentioning

confidence: 97%

“…Fluorescence-based biosensing [1][2][3][4] is a widely adopted approach for early-stage diagnosis but still faces challenges, 5,6 such as sensitivity, high throughput capability and adjustable sensing signal output. ZnO 7-9 is a semiconducting piezoelectric material with a direct band gap (3.37 eV) and large excitonbinding energy (60 mV) 7 which can form various nanostructures [6][7][8][10][11][12][13][14][15][16][17][18][19][20][21][22][23] via numerous established processes. Its usefulness has been demonstrated in a broad range of applications, such as solar cells 11,24 , piezoelectric nanogenerators 25,26 , light emitters 27 and optical waveguides 28 .…”

Section: Introductionmentioning

confidence: 99%

“…Recently, non-toxic ZnO nanostructures, such as aligned nanorods (NRs) forest and nanoflowers (NFs), have been fabricated as low-cost platforms for fluorescence enhancement, which can amplify the signal of fluorescencebased sensors. 6,12,[29][30][31][32][33][34][35][36][37][38][39] The most accepted mechanism to explain the fluorescent enhancement is the large evanescent electric field excited around the surface of the ZnO structure, that leads to increased excitation of the fluorophore. 33,40,41 Previous modelling studied by Börner et al 42 showed evanescent electric field enhancement close to the surface of the ZnO.…”

Section: Introductionmentioning

confidence: 99%

“…In the same study the fluorescent enhancement due to NFs was also studied under the same conditions and was found to be about 4 times higher than for aligned NRs, once corrected for increased surface area available for fluorophore attachment. Whilst our NF system 12,16 [ZnO rods grown on polystyrene spheres (PS)] shows superior performance in terms of fluorescence enhancement across the visible-light spectrum, it remains unclear to us whether the enhancement based on NFs can be tuned for the benefit of practical usage. The capability to tune the fluorescence enhancement on the same type of enhancement platform is quite useful, as it can offer the adjustability for signal output to prevent issues like signal saturation.…”

Section: Introductionmentioning

confidence: 99%

“…A closed-packed polystyrene monolayer on a bare glass was initially formed using a liquid interface-mediated method. 12,44 It was then converted to a non-close-packed PS monolayer by oxygen plasma size reduction 12,45,46 using Etchlab 200 (SENTECH Instruments GmbH). The diameter of the PS spheres was reduced from 800 nm to 400 nm.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Tuneable fluorescence enhancement of nanostructured ZnO arrays with controlled morphology

Wang

Centeno

Darvill

et al. 2018

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Zinc oxide (ZnO) nanorods (NRs) have been demonstrated as a promising platform for enhanced fluorescence-based sensing. It is, however, desirable to achieve a tuneable fluorescence enhancement with these platforms so that the fluorescence output can be adjusted based on the real need. Here we show that the fluorescence enhancement can be tuned by changing the diameter of the ZnO nanorods, simply controlled by potassium chloride (KCl) concentration during synthesis, using arrays of previously developed aligned NRs (a.k.a. aligned NR forests) and nanoflowers (NFs). Combining the experimental results obtained from ZnO nanostructures with controlled morphology and computer-aided verification, we show that the fluorescence enhancement factor increases when ZnO NRs become thicker. The fluorescence enhancement factor of NF arrays is shown to have a much stronger dependency on the rod diameter than that of aligned NR arrays. We prove that the morphology of nanostructures, which can be controlled, can be an important factor for fluorescence enhancement. Our (i) effort towards understanding the structure-property relationships of ZnO nanostructured arrays and (ii) demonstration on tuneable fluorescence enhancement by nanostructure engineering can provide some guidance towards the rational design of future fluorescence amplification platforms potentially for bio-sensing.

show abstract

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tuneable fluorescence enhancement of nanostructured ZnO arrays with controlled morphology

Wang

Centeno

Darvill

et al. 2018

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

Plasmonic Fluorescence Enhancement in Diagnostics for Clinical Tests at Point‐of‐Care: A Review of Recent Technologies

et al. 2022

View full text Add to dashboard Cite

Fluorescence‐based biosensors have widely been used in the life‐sciences and biomedical applications due to their low limit of detection and a diverse selection of fluorophores that enable simultaneous measurements of multiple biomarkers. Recent research effort has been made to implement fluorescent biosensors into the exploding field of point‐of‐care testing (POCT), which uses cost‐effective strategies for rapid and affordable diagnostic testing. However, fluorescence‐based assays often suffer from their feeble signal at low analyte concentrations, which often requires sophisticated, costly, and bulky instrumentation to maintain high detection sensitivity. Metal‐ and metal oxide‐based nanostructures offer a simple solution to increase the output signal from fluorescent biosensors due to the generation of high field enhancements close to a metal or metal oxide surface, which has been shown to improve the excitation rate, quantum yield, photostability, and radiation pattern of fluorophores. This article provides an overview of existing biosensors that employ various strategies for fluorescence enhancement via nanostructures and have demonstrated the potential for use as POCT. Biosensors using nanostructures such as planar substrates, freestanding nanoparticles, and metal–dielectric–metal nanocavities are discussed with an emphasis placed on technologies that have shown promise towards POCT applications without the need for centralized laboratories.

show abstract

Rainbows at the End of Subwavelength Discontinuities: Plasmonic Light Trapping for Sensing Applications

Farid

Dixon

Shayegannia

et al. 2021

Advanced Optical Materials

View full text Add to dashboard Cite

Surface plasmon polaritons (SPPs) which exist at the metal-dielectric interface are guided by the coupling of electromagnetic waves to oscillations in the electron gas plasma created at metal surfaces. Plasmonics, a subset of the field of nanophotonics pertaining to all things beyond the diffraction limit, has flourished and evolved significantly over the past decade offering practical utility to a variety of applications. [1] Notwithstanding the ohmic loss in metals and commensurate limited propagation lengths of SPPs, the ability to effectively concentrate light in nanoscale volumes and generate extremely high electric field intensities at discontinuities or subwavelength patterned surfaces offers unique opportunities to enhance lightmatter interactions for a diverse range of functionalities. [2] Trapping broadband electromagnetic radiation over a range of deep subwavelength guided modes in a given structure provides opportunities for light-matter interactions at the nanoscale. Use of materials-commonly metals-that exhibit negative dielectric permittivity (ε < 0) at optical frequencies provide an optimum solution for light localization. Nanometallic light concentrators, in contrast to their dielectric counterparts, can squeeze and localize light into subwavelength volumes with greater control and higher efficiency. [3] Such plasmonic light concentration can be achieved by either resonant or non-resonant structures. In resonant structures, SPPs are created by time-varying electric fields that exert a force on the negatively charged electron gas inside a metal. These oscillations are resonantly driven leading to a strong charge displacement at specific optical frequencies and concentration of the light field within the structures. [4] For non-resonant light concentration effects, Schuller et al. demonstrated subwavelength light localization by introducing a feed gap in the metal structure for retardation-based resonators. The gap builds up opposite charges across it whereby SPPs encounter a longitudinal electric field component causing strong sub-wavelength light localization. [2] The focus of this article is plasmonic devices that enable rainbow light trapping, a specific modality of nanoscale field enhancement in which trapped light is spatially separated This article presents recent advances in plasmonic multiwavelength rainbow light trapping, a field that has evolved over the last decade and today is an active area of research interest encompassing a manifold of potential applications which include optical biosensing, photodetection, spectroscopy, and medicine. Conventional plasmonic devices are designed and optimized to enhance optical performance at single wavelengths, and as such are not suitable for applications that require electromagnetic field localization at multiple frequencies or broad frequency ranges of interest. To overcome these limitations, the ability to slow and trap light at multiple wavelengths and at different spatial locations has attracted significant scientific attention and opened up n...

show abstract

Broadband enhanced fluorescence using zinc-oxide nanoflower arrays

Abstract: ZnO nanoflower arrays have significantly higher fluorescence enhancement than ZnO nanorod arrays, with broadband enhancement capability.

Cited by 31 publications

References 29 publications

Tuneable fluorescence enhancement of nanostructured ZnO arrays with controlled morphology

Tuneable fluorescence enhancement of nanostructured ZnO arrays with controlled morphology

Plasmonic Fluorescence Enhancement in Diagnostics for Clinical Tests at Point‐of‐Care: A Review of Recent Technologies

Rainbows at the End of Subwavelength Discontinuities: Plasmonic Light Trapping for Sensing Applications

Contact Info

Product

Resources

About