Magnetic Alignment of Fluorescent Nanowires

Tanase, M.; Bauer, Laura Ann; Hultgren, A.; Silevitch, D. M.; Sun, Li; Reich, Daniel H.; Searson, Peter C.; Meyer, Gerald J.

doi:10.1021/nl005532s

Cited by 283 publications

(223 citation statements)

References 24 publications

(33 reference statements)

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“…Therefore, the technology to achieve network films of organic MWs deposited from a dispersion with controlled alignment and density is acutely desired. The integration of inorganic and metallic wires into functional network films has been extensively explored by using a number of methods such as the flow cell method (26), electric field (27,28), magnetic field (29), electrospinning (30), chemical and biological surface-directed patterning (31,32), Langmuir-Blodgett technique (33,34), transfer-printing (35,36,37), and the blownbubble method (38). Compared with their inorganic counterparts, however, organic wires are typically mechanically less robust, electromagnetically less active, and broader in size distribution; hence, the aforementioned alignment techniques cannot easily be applied to them.…”

mentioning

confidence: 99%

Solution-processed, high-performance n-channel organic microwire transistors

Oh¹,

Lee²,

Mannsfeld³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

221

197

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The development of solution-processable, high-performance nchannel organic semiconductors is crucial to realizing low-cost, all-organic complementary circuits. Single-crystalline organic semiconductor nano/microwires (NWs/MWs) have great potential as active materials in solution-formed high-performance transistors. However, the technology to integrate these elements into functional networks with controlled alignment and density lags far behind their inorganic counterparts. Here, we report a solutionprocessing approach to achieve high-performance air-stable nchannel organic transistors (the field-effect mobility ( ) up to 0.24 cm 2 /Vs for MW networks) comprising high mobility, solutionsynthesized single-crystalline organic semiconducting MWs ( as high as 1.4 cm 2 /Vs for individual MWs) and a filtration-and-transfer (FAT) alignment method. The FAT method enables facile control over both alignment and density of MWs. Our approach presents a route toward solution-processed, high-performance organic transistors and could be used for directed assembly of various functional organic and inorganic NWs/MWs. organic semiconductors ͉ single crystals ͉ solution processing ͉ alignment S olution-processable, high-performance n-channel (electrontransporting) organic semiconductors are indispensable for cost-effective production of all-organic, flexible complementary logic elements (1-3). To date, however, very few solutionprocessable, air-stable organic n-channel semiconductors matching the performance of amorphous silicon (a-Si) ( Ն 0.1 cm 2 /Vs) have been reported (4-8). Organic semiconductor nano/microwires (NWs/MWs) have recently emerged as promising building blocks for various electronic and optical applications such as light-emitting diodes (LEDs) (9), field-effect transistors (FETs) (10), photoswitches (11), vapor sensors (12), solar cells (13), nanoscale lasers (14), optical waveguides (15), and memory devices (16). These unique materials combine the high-performance of singlecrystalline structures with solution-processability by dispersion (17,18). Several p-channel (hole-transporting) organic wires prepared by solution-processing have exhibited Ͼ 0.1 cm 2 /Vs for singlewire transistors (19)(20)(21)(22), whereas only a few solution-synthesized n-channel organic wires have been reported, typically with low performance ( Ϸ10 Ϫ3 Ϫ 10 Ϫ2 cm 2 /Vs) (23,24).Despite the intrinsic high mobility of single-crystalline wires, precise wire placement and wire-to-wire performance variation, due to the difference in the contact quality at the wire/insulator and wire/electrode interfaces, substantially hinder successful device integration (10, 25). Therefore, the technology to achieve network films of organic MWs deposited from a dispersion with controlled alignment and density is acutely desired. The integration of inorganic and metallic wires into functional network films has been extensively explored by using a number of methods such as the flow cell method (26), electric field (27, 28), magnetic field (29), electrospinning (30),...

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mentioning

confidence: 99%

Solution-processed, high-performance n-channel organic microwire transistors

Oh¹,

Lee²,

Mannsfeld³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

221

197

View full text Add to dashboard Cite

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“…The lengths of these chains were observed to extend over hundreds of micrometres, in agreement with the previous results. 33,40 Depending upon the concentration, the location and distance between these wires in addition to the magnetisation, the viscous drag, and the magnetic field strength, the inter-wire dipolar interactions can play an important role in the formation of chains during the deposition process.…”

Section: Resultsmentioning

confidence: 99%

“…32 In solution, magnetic alignment of nanostructures can enhance thermal conductivity, 40 and with fluorescent functionality, magnetic alignment has potential benefits for optical tracking in biotechnology applications. 33,44 Magnetic alignment can also be effectively applied to control and manipulate mammalian cells. 49 For applications where site-specific location and orientation of nanostructures is required, such as electronic circuits and sensors, global magnetic alignment in conjunction with other methods for locating the nanowires onto specified positions on a device structure can assist in the orientation of nanowires.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, a variety of techniques have been utilised to manipulate and control electrodeposited nanowires suspended in a solvent including thermocapillary motion of nanowire suspensions in microchannels, 25,26 electrostatics, [26][27][28] electric field, 26,29,30 and magnetic field [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] assisted alignment. Recently, magnetic field have been utilized by several researchers to control assembly and alignment of carbon nanotubes, 26,40 Ni, [31][32][33][34][35] semiconductor, 26 conductive polymer 26 nanowires, as well as metallic nanowires such as gold, 37,39 bismuth, 42 coppertin, 41 Pt, 43 and ZnO (Ref. 38) capped with Ni ends by manually drop casting a dilute suspension containing these nanowires between two electrodes predefined on a specimen by lithographic techniques and using two permanent magnets.…”

Section: Introductionmentioning

confidence: 99%

“…33,35,44 In addition, recent work demonstrated the use of magnetic alignment of electrodeposited ferromagnetic nanowires to create hierarchical structures. 34 Again, permanent magnets were used, this time for sequential alignment of the nanowires onto either unpatterned or pre-patterned ferromagnetic electrodes on substrates.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic field alignment of template released ferromagnetic nanowires

Sultan

Das

Mandal

et al. 2012

Journal of Applied Physics

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A detailed investigation of magnetic field alignment of template released ferromagnetic nanowires has been undertaken. The distributions of magnetic field induced angular alignments of Ni0.8Fe0.2, Co, and Ni nanowires grown by electro-deposition and deposited onto substrates from a dilute suspension have been investigated as a function of magnetic field strengths up to ∼1 kOe. The nominal diameter of the nanowires investigated is either ∼200 nm (Ni0.8Fe0.2) or ∼300 nm (Co and Ni). The percentage of nanowires aligned within 0°–10° and 0°–20° of the applied field axis is observed to increase rapidly with increasing field strength up to ∼200 Oe, followed by a slower increase in alignment for the Ni0.8Fe0.2 and Ni wires and little improvement in alignment for the Co wires at higher fields. The proportion of aligned wires within 0°–20° is found to reach ∼82% for Ni0.8Fe0.2, ∼71% for Ni and only 53% for the Co nanowires using a magnetic field of 1 kOe. The influence of wire length upon the efficacy of magnetic alignment is investigated using Ni0.8Fe0.2 and Ni nanowires; this showed that the fractional alignment improved for longer nanowires.

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Biological Applications of Multifunctional Magnetic Nanowires

Felton

Reich

2007

Biomedical Applications of Nanotechnology

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Nanoscale magnetic particles are playing an increasingly important role as tools in biotechnology and medicine, as well as for studying biological systems. With appropriate surface functionalization, they enable the selective application of magnetic forces to a wide range of cells, subcellular structures, and biomolecules, and have been applied to or are being developed for areas including magnetic separation, magnetic biosensing and bioassays, drug delivery and therapeutics, and probes of the mechanical and rheological properties of cells [1][2][3][4][5][6][7][8][9][10]. Despite these successes, however, the structure of the magnetic particles in common use limits the range of potential applications. Most biomagnetic particles available today are spherical, with either (a) a "core-shell" structure of concentric magnetic and nonmagnetic layers or (b) magnetic nanoparticles randomly embedded in a nonmagnetic matrix [2,11]. These geometries constrain the range of magnetic properties that can be engineered into these particles, as well as their chemical interactions with their surroundings, because such particles typically carry only a single surface functionality. A new and more versatile approach is to use asymmetric, multisegment magnetic nanoparticles, such as the metal nanowires shown in Figure 1.1.

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Magnetic Alignment of Fluorescent Nanowires

Cited by 283 publications

References 24 publications

Solution-processed, high-performance n-channel organic microwire transistors

Solution-processed, high-performance n-channel organic microwire transistors

Magnetic field alignment of template released ferromagnetic nanowires

Biological Applications of Multifunctional Magnetic Nanowires

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