Metacapacitors: Printed Thin Film, Flexible Capacitors for Power Conversion Applications

Tassell, Barry Van; Yang, Shyuan; Le, Chengrui; Huang, Limin; Liu, Shuangyi; Chando, Paul; Liu, Xiaohua; Byro, Andrew; Gerber, Dániel; Leland, Eli S.; Sanders, S.R.; Kinget, Peter R.; Kymissis, Ioannis; Steingart, Daniel Artemus; O’Brien, Stephen

doi:10.1109/tpel.2015.2448529

Cited by 16 publications

(8 citation statements)

References 52 publications

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“…Organic rectifying diodes already can work at tens of MHz 33 , 34 . Printed flexible 10 μF range multi-layer capacitors for power conversion applications have been demonstrated 35 and show a high relative dielectric constant of 15–22 up to 10 MHz. In addition to the high f T , the high current drive capability of the OPBT is also an advantage for compatibility with this application.…”

Section: Further Discussion and Conclusionmentioning

confidence: 99%

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

Kheradmand‐Boroujeni

Klinger

Fischer

et al. 2018

Sci Rep

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Organic/polymer transistors can enable the fabrication of large-area flexible circuits. However, these devices are inherently temperature sensitive due to the strong temperature dependence of charge carrier mobility, suffer from low thermal conductivity of plastic substrates, and are slow due to the low mobility and long channel length (L). Here we report a new, advanced characterization circuit that within around ten microseconds simultaneously applies an accurate large-signal pulse bias and a small-signal sinusoidal excitation to the transistor and measures many high-frequency parameters. This significantly reduces the self-heating and therefore provides data at a known junction temperature more accurate for fitting model parameters to the results, enables small-signal characterization over >10 times wider bias I–V range, with ~105 times less bias-stress effects. Fully thermally-evaporated vertical permeable-base transistors with physical L = 200 nm fabricated using C60 fullerene semiconductor are characterized. Intrinsic gain up to 35 dB, and record transit frequency (unity current-gain cutoff frequency, fT) of 40 MHz at 8.6 V are achieved. Interestingly, no saturation in fT − I and transconductance (gm − I) is observed at high currents. This paves the way for the integration of high-frequency functionalities into organic circuits, such as long-distance wireless communication and switching power converters.

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Section: Further Discussion and Conclusionmentioning

confidence: 99%

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

Kheradmand‐Boroujeni

Klinger

Fischer

et al. 2018

Sci Rep

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show abstract

“…The nanocrystals were shown to have a passivated surface layer of hydroxyl/alkyl groups, which allows the nanocrystals to exist in the form of a superstable and transparent sol or self-accumulate to form a highly crystalline solid gel monolith (hence “gel-collection”) of 100% yield for easy separation/purification. The dispersibility of the particles in solvents enables the generation of smooth nanocomposite thin films that can be spray printed or spin coated to make single and multilayer capacitors …”

Section: Introductionmentioning

confidence: 99%

Stoichiometric Control over Ferroic Behavior in Ba(Ti_1–xFe_x)O₃ Nanocrystals

et al. 2019

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Ba(Ti,Fe)O 3 is a useful system for the exploration of multiferroic properties as a function of composition and variation in structure, based upon a model of intersubstitution of the B site cation. Nanocrystals of Ba(Ti,Fe)O 3 could be used as building blocks for composite multiferroic materials, provided ferroic properties are recognizable at this length scale and Ti and Fe serve as ideal models for the case of d 0 versus d n in a ferroic perovskite. A series of iron-substituted barium titanate nanocrystals (BaTi 1−x Fe x O 3 ) were synthesized at 60 °C using a hybrid sol−gel chemical solution processing method. No further crystallization/ calcination steps were required. The as-prepared nanocrystals are fully crystalline, uniform in size (∼8 nm by TEM), and dispersible in polar organic solvents, yielding nanocrystal/alcohol formulations. Complete consumption of the reactant precursors ensures adequate control over stoichiometry of the final product, over a full range of x (0, 0.1 to 0.75, 1.0). Pair distribution function (PDF) analysis enabled in-depth structural characterization (phase, space group, unit cell parameters, etc.) and shows that, in the case of x = 0, 0.1, 0.2, 0.3, BaTiO 3 , and BaTi 1−x Fe x O 3 nanocrystals, it is concluded that they are tetragonal noncentrosymmetric P4mm with lattice parameters increasing from, e.g., c = 4.04 to 4.08 Å. XPS analysis confirms the presence of both Fe 3+ (d 5 ) and Fe 4+ (d 4 ), both candidates for multiferroicity in this system, given certain spin configurations in octahedral field splitting. The PDF cacluated lattice expansion is attributed to Fe 3+ (d 5 , HS) incorporation. The evidence of noncentrosymmetry, lattice expansion, and XPS conformation of Fe 3+ provides support for the existence of multiferroicity in these sub-10 nm uniform dispersed nanocrystals. For x > 0.5, Fe impacts the structure but still produces dispersible, relatively monodisperse nanocrystals. XPS also shows an increasing amount of Fe 4+ with increasing Fe, suggesting that Fe(IV) is evolving as charge compensation with decreasing Ti 4+ , while attempting to preserve the perovskite structure. A mixture of Fe 3+ /Fe 4+ is thought to reside at the B site: Fe 4+ helps stabilize the structure through charge balancing, while Fe 3+ may be complimented with oxygen vacancies to some extent, especially at the surface. The structure may therefore be of the form BaTi 1−x Fe x O 3-δ for increasing x. At higher concentrations (Fe > 0.5) the emergence of BaFeO 3 and/or BaFe 2 O 4 is offered as an explanation for competing phases, with BaFeO 3 as the likeliest competing phase for x = 1.0. Because of the good dispersibility of the nanocrystals in solvents, spin coating of uniform 0−3 nanocomposite BaTi 1−x Fe x O 3 /polyvinylpyrrolidone thin film capacitors (<0.5 μm) was possible. Frequency dependent dielectric measurements showed stable dielectric constants at 1 MHz of 27.0 to 22.2 for BaTi 1−x Fe x O 3 samples for x = 0−0.75, respectively. Loss tangent

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“…Ultrafine and highly dispersive nanoparticles have unique advantages in fabricating uniform composite structures [28]. Figs.…”

Section: Resultsmentioning

confidence: 99%

Highly dispersive Ba _0.6 Sr _0.4 TiO ₃ nanoparticles modified P(VDF‐HFP)/PMMA composite films with improved energy storage density and efficiency

Feng

Hao

et al. 2018

IET Nanodielectrics

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Polymer composite films with high energy density as well as high efficiency are promising dielectric materials in pulsed power systems. In improving the energy discharged efficiency, poly vinylidene fluoride-hexafluoropropylene [P(VDF-HFP)] film blended with 20 vol.% poly(methylmethacrylate) (PMMA), which has a much slimmer ferroelectric hysteresis loop, is employed as the polymer matrix. Highly dispersive Ba 0.6 Sr 0.4 TiO 3 (BST) nanoparticles with an average particle size of 12.1 nm are utilised to improve the polarisation of the blend film without sacrificing the dielectric strength. Uniform nanocomposite films with high flexibility and excellent energy-storage performance are obtained. Especially, due to the optimisation of both polymer matrix and fillers, the BST modified P(VDF-HFP)/PMMA blend films show improved breakdown strength and depressed energy loss, which leads to an enhanced energy density of 10.3 J/cm 3 at 378 kV/mm.

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Metacapacitors: Printed Thin Film, Flexible Capacitors for Power Conversion Applications

Cited by 16 publications

References 52 publications

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

Stoichiometric Control over Ferroic Behavior in Ba(Ti_1–xFe_x)O₃ Nanocrystals

Highly dispersive Ba _0.6 Sr _0.4 TiO ₃ nanoparticles modified P(VDF‐HFP)/PMMA composite films with improved energy storage density and efficiency

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Metacapacitors: Printed Thin Film, Flexible Capacitors for Power Conversion Applications

Cited by 16 publications

References 52 publications

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors

Stoichiometric Control over Ferroic Behavior in Ba(Ti1–xFex)O3 Nanocrystals

Highly dispersive Ba 0.6 Sr 0.4 TiO 3 nanoparticles modified P(VDF‐HFP)/PMMA composite films with improved energy storage density and efficiency

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Product

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Stoichiometric Control over Ferroic Behavior in Ba(Ti_1–xFe_x)O₃ Nanocrystals

Highly dispersive Ba _0.6 Sr _0.4 TiO ₃ nanoparticles modified P(VDF‐HFP)/PMMA composite films with improved energy storage density and efficiency