Proceedings Volume 9172

Nanostructured Thin Films VII

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Proceedings Volume 9172

Nanostructured Thin Films VII

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Volume Details

Date Published: 10 September 2014
Contents: 11 Sessions, 29 Papers, 0 Presentations
Conference: SPIE NanoScience + Engineering 2014
Volume Number: 9172

Table of Contents

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Table of Contents

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  • Front Matter: Volume 9172
  • Keynote Session
  • Functional Nanostructures I
  • Functional Nanostructures II
  • Towards Applications I
  • Theoretical and Numerical Studies
  • Characterization
  • Functional Nanostructures III
  • Towards Applications II
  • Fabrication
  • Poster Session
Front Matter: Volume 9172
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Front Matter: Volume 9172
This PDF file contains the front matter associated with SPIE Proceedings Volume 9172, including the Title Page, Copyright information, Table of Contents, Invited Panel Discussion, and Conference Committee listing.
Keynote Session
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Low dimensional optics
F. Flory, Ludovic Escoubas, J. Le Rouzo, et al.
Thanks to progresses in material science and nanotechnologies, surfaces and thin films can now be structured at different scales. Photonics components take benefit of this possibility to fulfill still more and more complex functions. They are composed as well of organic as inorganic materials, dielectric, semiconductor, and metallic materials, or a mixture of them. Multiscale and chiral structures can be used to control both spectral, spatial distribution of light together with its polarization state. The optical mode density in the near field and in the far field can then be designed in particular by combining more or less resonant structures for the optical waves, associating diffraction, interferences and anisotropic structures like Fabry-Perot, waveguide, plasmons, photonic crystals ... Artificially nanostructured materials often called metamaterials exhibit new properties. Different phenomena recently considered, including optical topological insulator and structures for vortex waves transporting angular momentum of photons, will be also discussed and illustrated. With the development of nanometer size structures another step is overtaken allowing the control of the intimate interaction of optical waves with materials to tune their basic electronic properties and permittivity. Both optical and electronic properties are also strongly dependent on coupling effects needing a global approach.
Functional Nanostructures I
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Confined modes on a meta-surface
Richard Razafindrakoto, Emmanuel Rousseau, Didier Felbacq, et al.
Meta–surfaces or 2D metamaterials are generally considered in the far-field. Because of their resonant properties, they possess also an interesting band structure in the near-field. A meta–surface made of a set of parallel nano- wires deposited on a surface was studied. Bloch waves localized on the surface exist in the vicinity of the anti-resonances of the nano-wires. This band-structure leads to strong variations in the efficiencies of the meta- surface seen as a diffraction grating.
Design a symmetrical film stack as a negative index metamaterial
In this work, the equivalent Herpin index and phase thickness of a symmetrical film stack that consists of a dielectric film D and a metal film M are analyzed using the film matrix method. Five-layered symmetrical MDMDM film stacks in which the thickness of each film is less than 1/10 of the incident wavelength are utilized. The positive real part of the equivalent Herpin index and the negative real part of the phase thickness result in a negative real part of the equivalent refractive index. The range of refractive indices of D and M that lead to a negative refractive index of the overall material is developed as a procedure. When a p-polarized light wave obliquely propagates into the material with the negative refractive index, negative refraction and backward wave propagation occur. To reduce the loss in the negative index metamaterial, a porous metal film is introduced as a substitute for the metal film M in MDMDM to increase the feasibility of the use of the metamaterial as an optical coating.
Functional Nanostructures II
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Nanostructured thin films and their macrobehaviors
The iridescence green band and cyan tail of the wing on Papilio blumei butterfly were investigated. The bi-color phenomenon on the scales of butterfly wings was found and analyzed. The spectral change with thickness of chitin-air layers, width of air hole, total layer numbers and incident angle of light were simulated by FDTD method. 2D photonic-crystal model was applied to explain the change of reflectance spectra and color with angle. The replica of structural color and nanostructured thin films for Papilio blumei butterflies was fabricated successfully by three main techniques, PS spheres bedding, electron-beam gun evaporation and ICP etching.
Nano-structures for high intensity fiber laser applications
C. Y. Ngo, L. Y. Hong, Z. Liu, et al.
High power fiber lasers are proposed to be a better candidate than conventional solid-state lasers for industries such as precision engineering since they are more compact and easier to operate. However, the beam quality generally degrades when one scales up the output power of the fiber laser. One can improve the output beam quality by altering the phase of the laser beam at the exit surface, and a promising method to do so is by integrating specially designed nano-structures at the laser facets. In fact, this method was recently demonstrated – by integrating gold concentric ring grating structures to the facet of a quantum cascade laser, one observes significant improvement in the beam quality. Nevertheless, to improve the beam quality of high power fiber lasers using the method mentioned above, the material of the nano-structures must be able to withstand high laser fluence in the range of J/cm2. In this work, we investigated the laser-induced damage threshold (LIDT) values of a suitable material for high intensity fiber laser applications. Consequently, we demonstrated that the shortlisted material and the fabricated nanostructures can withstand laser fluence exceeding 1.0 J/cm2.
PbS sculptured thin film and their effect on liquid crystals alignment
Lead Sulphide (PbS) sculptured thin film (STF) is prepared using glancing angle deposition (GLAD) technique by physical vapour deposition (PVD) process. The morphology of the GLAD films clearly shows that anisotropic structure is obtained and composed of micro-sheets having sharp top edges. Due to the orientational order of the GLAD PbS STF an attempt has been made to check its effect on the alignment of liquid crystals as one might expect strong effect to occur. The optical microscope images under crossed polarizer reveals that good alignment is observed. The transmission, birefringence and response time measurements have also been investigated.
Towards Applications I
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New physics and applications of apertures in thin metal films
The nanoplasmonic properties of apertures in metal films have been studied extensively; however, we have recently discovered surprising new features of this simple system with applications to super-focusing and super-scattering. Furthermore, apertures allow for optical tweezers that can hold onto particles of the order of 1 nm; I will briefly highlight our work using these apertures to study protein - small molecule interactions and protein - DNA binding.
Nanostructured refractory thin films for solar applications
E. Ollier, N. Dunoyer, O. Dellea, et al.
Selective solar absorbers are key elements of all solar thermal systems. Solar thermal panels and Concentrated Solar Power (CSP) systems aim respectively at producing heat and electricity. In both cases, a surface receives the solar radiation and is designed to have the highest optical absorption (lowest optical reflectivity) of the solar radiation in the visible wavelength range where the solar intensity is the highest. It also has a low emissivity in the infrared (IR) range in order to avoid radiative thermal losses. Current solutions in the state of the art usually consist in deposited interferential thin films or in cermets [1]. Structured surfaces have been proposed and have been simulated because they are supposed to be more efficient when the solar radiation is not normal to the receiving surface and because they could potentially be fabricated with refractory materials able to sustain high operating temperatures. This work presents a new method to fabricate micro/nanostructured surfaces on molybdenum (refractory metal with a melting temperature of 2623°C). This method now allows obtaining a refractory selective surface with an excellent optical selectivity and a very high absorption in the visible range. This high absorption performance was obtained by achieving a double structuration at micro and nano scales thanks to an innovative process flow.
Stretchable conducting materials with multi-scale hierarchical structures for biomedical applications
Electrogenetic tissues in human body such as central and peripheral nerve systems, muscular and cardiomuscular systems are soft and stretchable materials. However, most of the artificial materials, interfacing with those conductive tissues, such as neural electrodes and cardiac pacemakers, have stiff mechanical properties. The rather contradictory properties between natural and artificial materials usually cause critical incompatibility problems in implanting bodymachine interfaces for wide ranges of biomedical devices. Thus, we developed a stretchable and electrically conductive material with complex hierarchical structures; multi-scale microstructures and nanostructural electrical pathways. For biomedical purposes, an implantable polycaprolactone (PCL) membrane was coated by molecularly controlled layer-bylayer (LBL) assembly of single-walled carbon nanotubes (SWNTs) or poly(3,4-ethylenedioxythiophene) (PEDOT). The soft PCL membrane with asymmetric micro- and nano-pores provides elastic properties, while conductive SWNT or PEDOT coating preserves stable electrical conductivity even in a fully stretched state. This electrical conductivity enhanced ionic cell transmission and cell-to-cell interactions as well as electrical cellular stimulation on the membrane. Our novel stretchable conducting materials will overcome long-lasting challenges for bioelectronic applications by significantly reducing mechanical property gaps between tissues and artificial materials and by providing 3D interconnected electro-active pathways which can be available even at a fully stretched state.
Theoretical and Numerical Studies
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Engineering wavefront with Huygens, Fermat, Bragg, Friedel, and Fresnel laws (presentation video)
We propose a metasurface that generalizes classical Snell and Fresnel laws, based on phase discontinuities. I provide an outlook on this structure, from different and complementary points of view, referred to classical Huygens, Fermat, Bragg, Friedel and Fresnel laws. The structure shows a generalization of the concept of crystallographic systematic absence. As a result, the Friedel law of crystals completely breaks down. A novel concept of "metacrystal" can be introduced, where systematic absences can be originated from form factors of meta-atoms, in contrast with natural absences, which are based on structure factors only. Applications will be also presented.
Computer-based numerical simulations of adsorption in nanostructures
Diana Khashimova
Publisher’s Note: This paper, originally published on September 9, 2014, was replaced with a corrected/revised version on January 26, 2015. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.


Zeolites are crystalline oxides with uniform, molecular-pore diameters of 3-14Å. Significant developments since 1950 made production of synthetic zeolites with high purity and controlled chemical composition possible. In powder-form, zeolites are major role-players in high-tech, industrial catalysis, adsorption, and ion exchange applications. Understanding properties of thin-film zeolites has been a focus of recent research. The ability to fine-tune desired macroscopic properties by controlled alteration at the molecular level is paramount. The relationships between macroscopic and molecular-level properties are established by experimental research. Because generating macroscopic, experimental data in a controlled laboratory can be prohibitively costly and time-consuming, reliable numerical simulations, which remove such difficulties, are an attractive alternative. Using a Configurational Biased Monte Carlo (CBMC) approach in grand canonical ensemble, numerical models for pure component and multicomponent adsorption processes were developed. Theoretical models such as ideal (IAST) and real adsorbed solution theory (RAST) to predict mixture adsorption in nanopores were used for comparison. Activity coefficients used in RAST calculations were determined from the Wilson, spreading pressure and COSMO-RS models. Investigative testing of the method on known materials, represented by all-silica zeolites such as MFI (channel type) and DDR (cage type), proved successful in replicating experimental data on adsorption of light hydrocarbons - alkanes, such as methane, ethane, propane and butane. Additionally, adsorption of binary and ternary mixtures was simulated. The given numerical approach developed can be a powerful, cost and time saving tool to predict process characteristics for different molecular-structure configurations. The approach used here for simulating adsorption properties of nanopore materials including process characteristics, may have great potential for other properties of interest.
Waves in tape helix loaded liquid crystal optical fiber
This communication describes a rather new type of optical fiber composed of three layers with the outermost region being radially anisotropic liquid crystal, and the inner dielectric core-clad interface is loaded with conducting tape helix structure. Similarly to the fibers embedded with conducting sheath helix, the introduction of tape helix too would throw the impact of altering the dispersion features of the guide. However, the situation becomes more complex in the sense that, apart from the helix pitch angle (as generally considered in the case of sheath), the width of tape helix structure becomes the additional factor to affect the dispersion characteristics. We consider the core and the inner clad sections as made of linear, homogeneous and isotropic dielectrics, and the anisotropy remains in the outermost section due to the presence of nematic radially anisotropic liquid crystal material. Taking into account the zero-order guided modes in the fiber structure, effects on confinements due to the amalgamation of birefringence (optical property of liquid crystal) and tape helix pitch (geometrical/structural property of prefect conductor) are reported. Results reveal that such liquid crystal fibers with conducting tape helix loadings would be more useful than the sheath helix loaded fibers.
Shift happens: optical sensing with Dyakonov-Tamm waves
An optical modality to sense a fluid by exploiting Dyakonov-Tamm (DT) waves was devised. In the modality, the fluid is present on both sides of the guiding interface. Theory showed that the angular location of reflectance dip in a practically implementable configuration will shift if the refractive index of the fluid changes. Furthermore, the detection sensitivity will decrease as the refractive index of the fluid increases over a wide range, and should be comparable to that for sensing modalities that exploit surface-plasmon-polariton (SPP) waves. Higher sensitivities are available with DT waves than with SPP waves, and the DT-wave-based sensor should be simpler to fabricate than the SPP-wave-based sensor. Multiple DT waves are excitable at the same frequency, leading to multiple channels for more reliable sensing as well as for sensing multiple analytes simultaneously.
Voigt waves in electro–optic homogenized composite materials
A study was undertaken into Voigt wave propagation in a homogenized composite material (HCM). The HCM investigated arose from a porous electro–optic host material infiltrated by a fluid of refractive index na, considered in the long–wavelength regime. The extended Bruggeman homogenization formalism was employed to estimate the constitutive parameters of the HCM. In principle, the directions which support Voigt wave propagation in the HCM may be controlled by means of an applied dc electric field; and the degree of control may be sensitive to the porosity of the host material, the shapes, sizes and orientations of the pores, as well as the refractive index na. Here the theoretical methodology is presented; numerical results are presented elsewhere.
Characterization
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Local field enhancement effects for dielectric coatings on silver nanorod arrays
A slanted silver nanorod array (NRA) deposited with glancing angle of deposition around 89°. By controlling the deposition angle, SiO2 and Ta2O5 grow on sliver rods in different morphologies. The multilayer designed as high reflective multilayer by arranging SiO2 and Ta2O5 alternatively on a cylindrical silver rod with diameter of 80 nm and a length of 200 nm would enhance the local field intensity and scattering when the rod is illuminated by s-polarized and ppolarized light waves. In this work, the reflective multilayer is designed at wavelengths of 450nm and 750nm that are associated with transverse plasmonic mode and longitudinal plasmonic mode, respectively. It is demonstrated experimentally that the intensity of light scattering from the capped NRA is enhanced due to the local field confinement around silver rod.
Study of partial discharge characteristics of nano filled polypropylene films according to the variation in electric field distribution on the sample
Md. Afzalur Rab, Rohitha Dhara, Prathap Basappa, et al.
In this work, partial discharge (PD) measurements of natural nanofilled polypropylene (PP) films have been performed by systematically varying the air gap between rod and plane electrodes to study the effect of field variation on PD characteristics. Results indicated that Partial Discharge Inception Voltage (PDIV) increases when either the nanofiller concentration or air gap is increased. Further, during aging, average PD magnitude and Weibull Scale Factor of PD pulse distributions decrease with increase in air gap. Electric field simulation results agree with our experimental findings.
Ultra-thin metal oxide based light controlled converter for sensing surface chemicals
Arūnas Šetkus, Virginijus Bukauskas, Audružis Mironas, et al.
The thin film technology is used to intentionally combine functional properties of metal oxides at the nanoscale. An ultra thin construction of metal oxide layers is sandwiched between the metal contacts and a system with the gas sensitivity is made and characterized. The built in potential differences in the construction results a combination of the photovoltaic effect and the electrical response to the gas-surface interaction. The response is detected at the ambient temperature, it is sufficiently fast for the practical purposes and is reversible without and with assistance of light even if the response memristance exists. The parameters of the sensor can be intentionally modified by the thin film technology.
Magnetic, magnetooptical and magnetotransport properties of Ti-substituted Co2FeGa thin films
Vladimir Khovaylo, Valeria Rodionova, Maria Lyange, et al.
Magnetic, magnetooptical and magnetotransport properties of Co50.3Fe20.3Ti5.6Ga23.8 thin films were studied for the as prepared as well as annealed samples. Measurements of transverse magnetooptical Kerr effect revealed that the spectral response of the films strongly depends on the structural ordering which can be manipulated by annealing conditions. Peculiarities in the magnetic properties of the films were attributed to the coexisting phases with different degree of structural disorder. Magnetoresistance of Co50.3Fe20.3Ti5.6Ga23.8 thin films was found to be linear in the fields above 1 T which is typical for half-Heusler systems as well as for Heusler-based ferromagnetic shape memory alloys.
Functional Nanostructures III
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Investigation into the effect of space charges on the surface erosion of synthetic and natural organoclay nanofilled PP films
Rohitha Dhara, Md. Afzalur Rab, Prathap Basappa
Literature indicates space charge formation in the polypropylene (PP) films when subjected to Partial Discharges (PD). The space charge thus formed also alters the PD characteristics in turn altering the PD resistance. The main focus of this work is to investigate the effect of space charge formed during the PD aging process on the main field with minimal space charge redistribution times. AC Ramp voltage that constantly increases with time at a rate of 667 V/s was applied across the samples for 20 second duration. PP films with natural organo clay nanofillers (0 (wt/v) % referred to as PP+N0% (base polymer) and 2 (wt/v) % referred to as PP+N2%), and synthetic organo clay nanofillers (2 (wt/v) % referred to as PP+S2%) were considered for experimentation. Results indicate that with the inclusion of the either natural or synthetic organo clay nanoparticles, with in the percolation threshold limit of nanofiller concentration, the final electric stress is reduced thus enhancing the resistance to surface PDs.
Optical properties of porphyrin: graphene oxide composites
M. Harsha Vardhan Reddy, Rusul M. Al-Shammari, Nebras Al-Attar, et al.
In this work we aim to (via a non-invasive functionalization approach) tune and alter the intrinsic features of optically “transparent” graphene, by integrating water-soluble porphyrin aggregates. We explore the potential to combine porphyrin aggregates and graphene oxide to assess the advantages of such as a composite compared to the individual systems. We apply a range of optical spectroscopy methods including photo-absorption, fluorescence assess ground-state and excited state interactions. Our studies show that comparing resonant Raman scattering with optical transmission and fluorescence microscopy that the presence of influences the microscopic structures of the resulting composites.
Towards Applications II
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Nanocrystalline cellulose for optical encryption
Yu Ping Zhang, Karen Allahverdyan, Timothy Morse, et al.
Nanocrystalline cellulose (NCC) exhibits unusual optical properties that make it of interest for hierarchical optical encryption in nanostructured films. The color-travel phenomenon of iridescence is exhibited by NCC when cast as a film from chiral nematic aqueous phase suspensions of the nanocrystals. “Iridescence by self-assembly” has potential for overt encryption as an anti-counterfeiting measure. It also offers an intrinsic level of covert encryption by reflecting leftcircularly polarized light. We show that addition of a UV sensitive dye adds another level of (covert) encryption, and that specially prepared films manifest a rare form of optical non-reciprocity that does not require the application of an external field. Chirality parameters and stokes vector analyses suggest a simple authentication scheme. The method uses a UV light source and a circular polarizer in conjunction with an iridescent feature that can be verified by the eye or by chiral spectrometry.
Optical, electrical and structural study of metallic nano-structured thin films fabricated by oblique angle deposition
Various metallic nano-structured thin films were fabricated by oblique angle deposition. Their optical, electrical and structural properties were investigated to explore potential applications in optoelectronic field. The shape, size and density of metal films were discussed based on SEM images and their thermal characteristics. The optical reflectance, transmittance, and absorptance measurements showed unique optical properties of each metallic nano-structured films. Indeed, ellipsometry measurement and resistance measurement were performed to investigate directivity of nanocolumnar films depending on polarization properties, and conductivity, respectively.
Mimumes for SUBTLE applications
Inspired by natural multifunctionality, mimumes are microfibrous multifunctional metamaterials. Their microfibrosity engenders multifunctionality. Poly(p-xylylene) polymers that are currently used in bulk non-fibrous forms for packaging and tribological applications in electronic and biomedical arenas are excellent initial candidates to fabricate mimumes. In microfibrous forms, these polymers are expected to display simultaneous ultrasonic, biomedical, terahertz, light, and energy (SUBTLE) functionalities, thereby furthering the paradigm of design for system performance.
Fabrication
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Bottom-up fabrication of non-close-packed nanopillar arrays for photonic applications
Motofumi Suzuki, Shinta Suganuma, Yasuyuki Kaneko
We propose a fully bottom-up process to fabricate photonic polycrystalline over a large area at a low cost. By combining self-assembled polystyrene nanospheres and the oblique deposition technique, periodic arrays of nanospherical crown shells are obtained as a template. Non-close-packed nanopillar arrays are successfully fabricated by oblique-angle deposition on the template. The resulting nanopillar arrays exhibit some transmittance minima, which are understood in terms of the photonic band modes. Because the process proposed in this paper has advantages to obtain the photonic polycrystalline over a large area at a low cost, it can be applied to produce thermal infrared emitters with wavelength and directional tunabilities.
Tungsten-oxide thin films of dense, columnar, and chiral morphologies
Tomas Tolenis, Stephen E. Swiontek, Akhlesh Lakhtakia, et al.
Tungsten-oxide thin films of three different morphologies-dense, columnar, and chiral-were fabricated by evaporation at low pressure. The morphologies were observed using a scanning-electron microscope and their optical transmission spectrums were also recorded. The CTF discriminated between normally incident light of different linear polarization states. The chiral STF exhibited the circular Bragg phenomenon. Annealing blue-shifted and widened the circular Bragg regime.
The effect of the substrate temperature and the acceleration potential drop on the structural and physical properties of SiC thin films deposed by TVA method
Victor Ciupina, Cristian P. Lungu, Rodica Vladoiu, et al.
Crystalline Si-C thin films were prepared at substrate temperature between 200°C and 1000°C using Thermionic Vacuum Arc (TVA) method. To increase the acceleration potential drop a negative bias voltage up to -1000V was applied on the substrate. The 200nm thickness carbon thin films was deposed on glass and Si substrate and then 200-500 nm thickness Si-C layer on carbon thin films was deposed. Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), X-Ray Photoelectron Spectroscopy (XPS), and electrical conductivity measurement technique characterized the structure and physical characteristics of as-prepared SiC coating. At a constant acceleration potential drop, the electrical conductivity of the Si-C films deposed on C, increase with increasing of substrate temperature. On the other part, significant increases in the acceleration potential drop at constant substrate temperature lead to a variation of the crystallinity and electrical conductivity of the SiC coatings XPS analysis was performed using a Quantera SXM equipment, with monochromatic AlKα radiation at 1486.6eV. Electrical conductivity of the Si-C coating on carbon at different temperatures was measured comparing the potential drop on the sample with the potential drop on a series standard resistance in constant mode.
Poster Session
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Deposition condition influence on optical properties of indium tin oxide
Taras O. Hanulia, Olga Lopatynska, Vasyl V. Lendel, et al.
Indium tin oxide (ITO) is a solid solution of indium (III) oxide (In2O3) and tin (IV) oxide (SnO2). It is a typical object for research in modern optoelectronics. This material combines high transparency (in the visible) and conductivity simultaneously. It is used in the production of transparent electrodes of liquid crystal screens and solar cells. The optical properties of thin films of ITO were investigated using ellipsometry. Optical constants of these films were calculated using obtained ellipsometric parameters. Films thicknesses are equal to 21-34 nm, and their refractive indices vary in interval of 2,05-2,12. Also, it was found out how the deposition conditions of ITO films influences their optical properties.
Effect of aging with partial discharges on the remnant breakdown strength of polypropylene films with natural and synthetic nanofillers
Md. Afzalur Rab, Rohitha Dhara, Prathap Basappa, et al.
Uniform dispersion of small amounts of nanofillers into Polypropylene (PP) base polymer have shown to improve the dielectric properties such as Partial Discharge (PD) resistance and breakdown strength (BDS). A comparative analyses of the effect of addition of natural and synthetic nanofillers on the PD characteristics and the BDS prior to and after aging with PD have been performed. Results indicate that addition of both type of fillers significantly reduce maximum PD magnitude (Qmax). The Weibull characteristic BDS magnitudes were observed to improve with addition of nanofillers.