Effects of mechanical strain on optical properties of ZnO nanowire

Vazinishayan, Ali; Lambada, Dasaradha Rao; Yang, Shuming; Cheng, Biyao; Woldu, Yonas Tesfaye; Shafique, Shareen; Wang, Yiming; Ndahimana, Anastase

doi:10.1063/1.5016995

Cited by 15 publications

(6 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This change in refractive index will also influence DoF, as a strain condition yielding a higher refractive index can enable more coupling of light waveguided towards the NR ends. Insights from previous studies involving the NR’s intrinsic emission properties indicated that, under tension (compression), a smaller (larger) bandgap is measured relative to an unstrained case [ 30 , 31 , 32 , 33 ]. In other studies, an inverse relationship between the bandgap and refractive index of a semiconducting material has been shown [ 37 , 38 ].…”

Section: Resultsmentioning

confidence: 99%

“…For example, strain-altered ZnO NRs have been shown to alter their Schottky barrier height [ 25 , 26 ] and electrical conductance [ 27 , 28 , 29 ]. Strain was also used to change the near band-edge emission of ZnO nanowires [ 30 , 31 , 32 , 33 ], to shift the lasing modes of ZnO microwires [ 24 ], and to alter the phonon frequencies of ZnO NR Raman modes [ 34 ]. These past studies demonstrated how optical signals emitted from the ZnO nanomaterial itself such as the band-edge, photoluminescence, and lasing emissions can be modulated by applying stress.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elucidation of Strain-Dependent, Zinc Oxide Nanorod Response for Nanorod-Guided Fluorescence Intensity

et al. 2022

View full text Add to dashboard Cite

In this work, we examine how strain exerted on individual ZnO nanorods (NRs) can influence the fluorescence signals that are emitted from fluorophore molecules and subsequently coupled into and guided along the NR. We elucidate the relationships between the incremental levels of compressive and tensile strain on the NRs and measured fluorescence intensity of a model fluorophore, rhodamine 6G (R6G), as a function of the position on the NRs. We reveal that compressive strain on the NRs leads to a decrease in the guided fluorescence signal, while tensile strain leads to an increase in the fluorescence intensity. Compared to an unstrained state, approximately 35% decrease (increase) in R6G fluorescence intensity was observed from ZnO NRs when they were under compressive strain of −14% (tensile strain of +10%). Further, our systematic acquisition of the incremental addition of uniaxial strain result in a linear relationship of the coupled fluorescence signal and the amount of applied strain. The degree of fluorescence intensification on nanorod ends (DoF), which is a quantitative indicator for the amount of R6G signals coupled into and waveguided to the NR ends compared to those on the main body, also exhibits a linear relationship with strain. These outcomes, in turn, demonstrate that strain alters the waveguiding capabilities of ZnO NRs in a predictable manner, which can be exploited to modulate and optimize fluorescence and other light signals emitted by a nearby source. Considering the wide utility of ZnO NRs in photonics, optoelectronics, and sensors, insights from our study may be highly valuable to effectively controlling and enhancing optical signals from chemical and biological analytes through strain.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Elucidation of Strain-Dependent, Zinc Oxide Nanorod Response for Nanorod-Guided Fluorescence Intensity

et al. 2022

View full text Add to dashboard Cite

show abstract

“…These properties, obtained in flexible and conformable fiber mats, make these materials highly interesting for various applications in sensing and light-emitting devices, bioimaging, and photo-cross-linking as well as in network and bendable microlasers. Upon engineering the strength of the ZnO/polymer interface through proper surface modifiers or cross-linking of the organic matrix, one could also aim to obtain effective strain and load transfer to the inorganic component, , a perspective highly interesting for opto-mechanical coupling, and to exploit the piezoelectric properties of NWs in the hybrid material.…”

Section: Discussionmentioning

confidence: 99%

Conformable Nanowire-in-Nanofiber Hybrids for Low-Threshold Optical Gain in the Ultraviolet

et al. 2020

View full text Add to dashboard Cite

The miniaturization of diagnostic devices that exploit optical detection schemes requires the design of light-sources combining small size, high performance for effective excitation of chromophores, and mechanical flexibility for easy coupling to components with complex and non-planar shapes. Here, ZnO nanowire-in-fiber hybrids with internal architectural order are introduced, exhibiting a combination of polarized stimulated emission, low propagation losses of light modes, and structural flexibility. Ultrafast transient absorption experiments on the electrospun material show optical gain which gives rise to amplified spontaneous emission, with threshold lower than the value found in films. These systems are highly flexible and can conveniently conform to curved surfaces, which makes them appealing active elements for various device platforms, such as bendable lasers, optical networks and sensors, as well as for application in bioimaging, photo-crosslinking, and optogenetics.The development of miniaturized and effective light sources with emission in the near ultraviolet (UV) is highly important for all those fields, including microanalysis through fluorescence spectroscopy, chemical sensing, and healthcare diagnostics, where molecular photoexcitation is involved. 1-4 Together with mechanical flexibility to have them conformed to different surfaces or lodged within different lab-on-chip platforms, 2,3,5,6 UV-active materials are desired to feature stimulated emission and optical gain, which is the basic prerequisite to use them in compact laser systems and photonic networks. Examples of UV-emitters include various inorganics (GaN, ZnS, ZnO, etc.) and their nanostructures grown through chemical vapour transport processes, colloidal synthesis, and other deposition methods. 7-12 Inorganic nanostructures, and especially nanowires (NWs), have been largely exploited within semiconductor-embedding optical cavities, plasmonic nanolasers, and heterojunctions. 7,9,12,13 However, the so-obtained devices are largely limited to planar systems or substrates for nanostructure growth, they are mechanically stiff, and unconformable to curved surfaces.Polymeric light-emitting materials and films, 3,14-17 instead, can be easily coupled with bendable substrates and are more versatile in terms of configurational motifs, although their optical performance and stimulated emission properties are generally much less appealing and stable in time compared to inorganics.Hybrid approaches, inserting highly-efficient and stable oxide nanosystems in flexible polymer nanostructures and enabling high throughput processing, would combine advantages of UV lightemitting inorganics and plastic matrices, and potentially lead to materials with enhanced properties. For instance, in these systems light from UV nanoscale emitters could be efficiently coupled to polymer waveguides and transported along macroscale distances, 3,18 thus overcoming the high propagation losses typical of individual inorganic nanostructures 19 and enabling a much Published i...

show abstract

“…As such, previous works have used mechanical strain to modify the resistance [21], near band emission [17,19,20,22], and Schottky barrier height [23,24] of ZnO NWs. Simulation studies based on the finite element method (FEM) and three-dimensional (3D) finite difference time domain (FDTD) have also reported that the optical properties of ZnO NWs, such as reflectance, transmittance, and absorptance, are dependent on the applied mechanical strain [25][26][27]. These previous efforts have demonstrated that the intrinsic optical properties of ZnO nanostructures can be controlled through the application of strain.…”

Section: Introductionmentioning

confidence: 99%

Strain-Modulated and Nanorod-Waveguided Fluorescence in Single Zinc Oxide Nanorod-Based Immunodetection

Sytu,

Stoner,

Hahm

2024

Biosensors

View full text Add to dashboard Cite

Mechanical strain has been shown to be a versatile and tunable means to control various properties of nanomaterials. In this work, we investigate how strain applied to individual ZnO nanorods (NRs) can affect the fluorescence signals originated from external sources of bioanalytes, which are subsequently coupled and guided onto the NRs. Specifically, we determine how factors such as the NR length and protein concentration can influence the strain-induced changes in the waveguided fluorescence intensity along the NRs. We employ a protein of tumor necrosis factor-α (TNF-α) and a fluorophore-labeled antibody in a model immunoassay reaction, after which Alexa488-TNF-α immunocomplex is formed on ZnO NRs. We elucidate the relationships between the types as well as amounts of strain on the NRs and the fluorescence intensity originated from the Alexa488-TNF-α immunocomplexes. We show that tensile (compressive) strain applied to the NR leads to an increase (decrease) in the waveguided fluorescence signals. By assessing important optical phenomena such as fluorescence intensification on nanorod ends (FINE) and degree of FINE (DoF), we confirm their linear dependence with both the types and amounts of strain. Furthermore, the strain-induced changes in both FINE and DoF are found to be independent of protein concentration. We determine that NR length plays a critical role in obtaining high strain-dependence of the measured fluorescence signals. Particularly, we ascertain that longer NRs yield larger changes in both FINE and DoF in response to the applied strain, relative to shorter ones. In addition, longer NRs permit higher linear correlation between the protein concentration and the waveguided fluorescence intensity. These outcomes provide valuable insight into exploiting strain to enhance the detection of optical signals from bioanalytes, thus enabling their quantifications even at ultra-trace levels. Coupled with the use of individual ZnO NRs demonstrated in our measurements, this work may contribute to the development of a miniaturized, highly sensitive biosensor whose signal transduction is best optimized by the application of strain.

show abstract

Effects of mechanical strain on optical properties of ZnO nanowire

Cited by 15 publications

References 54 publications

Elucidation of Strain-Dependent, Zinc Oxide Nanorod Response for Nanorod-Guided Fluorescence Intensity

Elucidation of Strain-Dependent, Zinc Oxide Nanorod Response for Nanorod-Guided Fluorescence Intensity

Conformable Nanowire-in-Nanofiber Hybrids for Low-Threshold Optical Gain in the Ultraviolet

Strain-Modulated and Nanorod-Waveguided Fluorescence in Single Zinc Oxide Nanorod-Based Immunodetection

Contact Info

Product

Resources

About