Abstract:
An electrically transductive device, including a substrate having an electrically conducting surface portion, a first film of semiconducting nanoparticles positioned on the electrically conducting portion and further including a first plurality of close packed first generally spherical particles defining a first plurality of interstices and a second plurality of second, smaller generally spherical particles substantially filling the plurality of interstices, and a first coating of electrically conductive metal deposited over the first film.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to U.S. provisional patent application Ser. No. 61,550,893, filed on Oct. 24, 2011; copending U.S. provisional patent application Ser. No. 61/495,626, filed on Jun. 10, 2011; and to copending U.S. provisional patent application Ser. No. 61/418,232, filed on Nov. 30, 2010. 
    
    
     BACKGROUND 
     Electrophoretic deposition is a process by which particles desired to be plated or deposited onto a substrate are first colloidally suspended and then urged out of suspension and onto a substrate by means of an applied electric field. The desired coating material is provided as an amount of colloidal particles suspended in a liquid (typically aqueous) medium. The particles are imparted a surface charge, and thus migrate under the influence of an applied electric field to be deposited onto a charged substrate, which acts as an electrode. The colloidal particles can be polymeric, metallic or ceramic, so long as they can hold a surface charge. 
     Electrophoretic deposition may be used for applying charged colloidal materials to any substrate that is, or that can be made, electrically conductive. Aqueous colloidal suspensions are typical of electrophoretic deposition. Non-aqueous electrophoretic deposition applications are being explored, but are still in their infancy and are primarily attractive for applications requiring voltages high enough to electrolyze water, which may result in the evolution of undesired amounts of oxygen. 
     Electrophoretic deposition is typically used to apply coatings to metallic items, such as machine parts, metallic structural members, containers, and the like. Current manufacturing methods for deposition of thin films onto substrates, such as silicon films for photovoltaic applications, typically utilize a vacuum environment in order to lower the crystallization temperatures of the amorphous silicon material used as a silicon source and deposited onto the substrate for subsequent heating and recrystallization. However, the electrophoretic deposition process is more difficult to control as the size of the suspended particles decreases. As coatings made up of smaller, nanoscale particles having interesting and useful properties are desired, there thus arises a need to an improved electrophoretic deposition process for providing such coatings. The present novel technology addresses this need. 
     SUMMARY 
     The novel technology relates to an amplified piezoelectric effect resulting from quantum confined silicon and germanium nanocrystals synthesized in a predetermined state of stress. The nanoscale piezoelectric effect may be amplified by nanoparticles having a crystalline core surrounded by an amorphous shell and/or a crystalline core coated by a chemically different material, crystalline or amorphous. The increase to the nanoscale piezoelectric effect arises from higher relative strain induced at the interface of the core-shell nanoparticles from the difference in coefficient of thermal expansion between the amorphous shell and the crystal core and/or from the mismatch of interatomic spacing between the vitreous shell and crystal core. Typically, the shell compresses the core, but may alternately contribute tensile stresses. Particles are deposited onto a conductive substrate by electrophoretic deposition and self-align according to their respective dipole moments to form a unified Weiss domain throughout the film. Internal stress in the particles making up the film can be increased by intercalation of smaller atoms, such as lithium. Lithium intercalation into the nanocrystals results in a further increase in internal stress and a subsequent increase in the energy density achievable within the film. Typically, a metal film is deposited to protect the nanoparticle film. The metal contact also serves as a conduit for transferring energy stored in the film to an external device. 
     One object of the present novel technology is to provide an improved high energy density power storage and discharge device. Related objects and advantages of the present novel technology will be apparent from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an exploded view of a semiconducting nanocrystalline film deposited on a conductive substrate according to a first embodiment of the present novel technology. 
         FIG. 1B  is an exploded view of a plurality semiconducting nanocrystalline films separated by electrically conducting layers as deposited on a conductive substrate according to a second embodiment of the present novel technology. 
         FIG. 2  is a perspective view of an assembly for depositing the film of  FIG. 1  onto a substrate. 
         FIG. 3  is a process chart illustrating the fabrication of one or more devices according to the embodiment of  FIG. 1 . 
         FIG. 4  is a TEM photomicrograph perspective view of a strained silicon nanocrystal having an amorphous silicon shell encapsulating a purified crystalline silicon core. 
         FIG. 5  is an enlarged TEM photomicrograph view of a portion of the crystal of  FIG. 4 . 
         FIG. 6  graphically illustrates an EDX plot for the crystal of  FIG. 4 . 
         FIG. 7A  graphically illustrates an XRD plot comparing the strained silicon 111 crystal plane of the crystal of  FIG. 4  to a standard unstrained silicon 111 plane. 
         FIG. 7B  graphically illustrates an XRD plot comparing the strained silicon 111 crystal plane of the crystal of  FIG. 4  to a standard unstrained silicon 111 plane, corrected for contributions from an ITO conductive layer and the amorphous glass halo and/or shell surrounding the silicon crystal. 
         FIG. 8  graphically illustrated the crystal structure of strained silicon. 
         FIG. 9  is a TEM photomicrograph of a strained silicon nanocrystal having observable lattice planes. 
         FIG. 10  is a TEM photomicrograph of a plurality of strained silicon nanocrystals, each having observable lattice planes. 
         FIG. 11  graphically illustrates an EDX analysis of the nanocrystals of  FIG. 10 .  FIG. 12  graphically illustrates an XRD plot for the crystals of  FIG. 10  showing the shift of the 111 plane due to induced strain. 
         FIG. 13  is an SEM image of a layer of smaller (9 nm) silicon nanocrystals deposited over a layer of larger (25 nm) silicon nanocrystals. 
         FIG. 14  is an exploded view of a internally strained semiconducting nanocrystalline film deposited on a conductive substrate according and defining a voltage source a third embodiment of the present novel technology. 
         FIG. 15  is an exploded view of a internally strained semiconducting nanocrystalline film deposited on a conductive substrate according and in an electrolyte medium and defining a voltage source a third embodiment of the present novel technology. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the novel technology, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the novel technology is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the novel technology as illustrated therein being contemplated as would normally occur to one skilled in the art to which the novel technology relates. 
     Piezoelectric Effect 
     Piezoelectricity is the special circumstance of electrical charge build-up that arises in certain solid material structures due to mechanical stress. Generally, the piezoelectric effect has been experimentally determined to be a linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process such that the internal generation of electrical charge resulting from an applied mechanical force can be reversed with the internal generation of a mechanical strain resulting from an applied electrical field. 
     Piezoelectric Effect in Semiconductors 
     In semiconductors, changes in inter-atomic spacing resulting from strain affects the semiconductors intrinsic band gap making it easier (or harder depending on the material and strain) for electrons to be raised into the conduction band. The piezoelectric effect of semiconductor materials can be several orders of magnitudes larger than the analogous geometrical effect in metals and is present in materials like germanium, polycrystalline silicon, amorphous silicon, silicon carbide, and single crystal silicon. 
     The piezo effects of semiconductors have been used for sensor devices with a variety of semiconductor materials such as germanium, polycrystalline silicon, amorphous silicon, and single crystal silicon. Since silicon is currently the material of choice for nearly all integrated circuits, the use of piezoelectric silicon devices has been an intense area of research interest. 
     Piezoresistive Effect in Single Crystal Silicon and Germanium 
     The resistance of silicon and germanium can change due to a stress-induced change of geometry, but also due to the stress dependent resistivity of the material. The resistance of n-type silicon (predominant charge carriers responsible for electrical conduction are electrons) mainly changes due to a shift of the three different conducting vertices of the crystal. The shifting causes a redistribution of the carriers between vertices with different mobilities. This results in varying mobilities dependent on the direction of current flow. A minor effect is due to the effective mass change related to shape distortion due to change in the inter-atomic spacing of valley vertices in single crystal silicon. In p-type silicon (predominant charge carriers responsible for electrical conduction are holes) the phenomena currently being researched are more complex and also demonstrate changes in mass and hole transfer. 
     Detailed Description of Piezoelectric Mechanism 
     The nature of the piezoelectric effect is rooted in the occurrence of electric dipole moments in solids. An electric dipole moment is a vector quantity equal to the product of the magnitude of charge and the distance of separation between the charges. Electric dipole moments in solids may either be induced for ions on crystal lattice sites as in an asymmetric charge environment such as in lithium tantalate and lead zirconate-titanate or may be directly carried by molecular groups such as in organic sugar molecules. The dipole density causing polarization is the sum of the dipole moments per unit volume of a crystal unit cell. Since electric dipoles are vector quantities (geometric objects of specific magnitude and direction), the dipole density P is also a vector quantity. Dipoles near each other tend to be aligned in regions called Weiss domains. In these aligned regions occurring between individual particles, the particles act as a whole thus the potential and polarity of voltage and magnitude and direction of the current is equal to the sum of all individual particles making up the entire solid. 
     To reiterate, typically the piezoelectric effect typically occurs with an applied mechanical stress but can also be manifested by manufacturing internal stress into certain solids. Piezoelectricity arises in a variation of the polarization strength, its direction or both. The magnitude and direction of the charge depends on the interrelationships between the orientation of P within individual particles, particle symmetry, and the applied mechanical stress or induced internal stress. Although the change in an individual crystal&#39;s dipole density appears quantitatively as a variation of surface charge density upon the individual crystal faces, the overall useful energy arising from the piezoelectfic phenomenon is caused by superposition of the dipole densities of the crystals that make up the entire piece of material, i.e., as a sum of the individual crystallographic unit cells that make up a whole crystal. For example, a 1 cm 3  cube of quartz with 500 lb of mechanically applied force at the right point can produce a voltage of 12500 V because the resultant force is the sum of all the individual crystallographic unit cells that make up the whole crystal. 
     Power Generation in Polar Crystal Structures Synthesized in a State of Stress 
     There are 32 crystal classes that represent 32 possible combinations of symmetry operations in crystalline materials. Each crystal class includes crystal faces that uniquely define the symmetry of the class. Of the thirty-two crystal classes, twenty-one are non-centrosymmetric (not having a centre of symmetry), and of these, twenty exhibit direct piezoelectricity. Ten of these include the polar crystal classes, which show a spontaneous polarization without an applied mechanical stress due to a non-vanishing electric dipole moment associated with asymmetry inherent in their crystal structure. For polar crystals, for which the summation of the dipole density P≠0 holds without applying a mechanical load, the piezoelectric effect manifests itself by changing the magnitude or the direction of P or both. Stated another way, polar crystals that can be manufactured to have internal stress will demonstrate a piezoelectric effect without an applied mechanical load. 
     Restated another way, for non-polar piezoelectric crystals, an applied mechanical load transforms the material from a non-polar crystal class (P=0) to a polar one, having P≠0 and hence gives rise to a voltage potential and useful energy capable of powering an external device. However, crystals predisposed to an internal state of stress have an inherent polar structure for which P≠0 and hence energy can be discharged from the structure without an applied mechanical load. During discharge of electrical energy, the crystal relaxes back into its preferred state of interatomic spacing. 
     Quantum Confinement in Nanoparticles 
     Quantum confinement in nanocrystals is an important concept to grasp. Quantum confinement in nanocrystals occurs when the physical size of the particle is less than its characteristic exciton Bohr radius. The exciton Bohr radius is the physical distance separating a negatively charged electron from its positively charged hole left behind during excitation. When the physical size of the particle is less than the distance the electron must travel during excitation, the material is considered to be quantum confined. For example, the exciton Bohr radius for germanium is 24.3 nm; however, it is possible to synthesize germanium nanocrystals to be 1 nanometer in diameter. By creating nanoparticles smaller than this characteristic distance, the electronic properties of the nanoparticles can be tuned to discreet energy levels by adjusting particle size. Thus, an aggregate made of particles smaller than the Bohr radius will enjoy a greatly increased energy density. If the particles are about the same size as the Bohr exciton radius, or even a little larger, an aggregate of the particles will still enjoy increased energy density, if not to the same degree as if all of the particles were smaller than the exciton Bohr radius. 
     Another important concept to understand is that of potential wells and how they arise in nanoparticles. Potential wells are a direct result of synthesizing physical particle dimensions to be smaller than their respective exciton Bohr radius. A potential well is the region surrounding a local minimum of potential energy in nanomaterials. Energy captured in a potential well is unable to convert to another type of energy because it is captured in the local minimum of the potential well. Therefore, a body may not proceed to the global minimum of potential energy, as it naturally would according to the universal nature of entropy. 
     Energy may be released from a potential well if sufficient energy is added to the system such that the local minimum energy for excitation is sufficiently overcome. However, in quantum physics potential energy may escape a potential well without added energy due to the probabilistic characteristics of quantum particles. In these cases, a particle may be imagined to tunnel through the walls of a potential well without energy added to the system. 
     As illustrated in  FIGS. 1A-3 , the present novel technology relates to a method of producing a coating or film  10  on a substrate  15  under conditions of ambient atmospheric composition and pressure, and ambient or slightly elevated temperature, by electrophoretically extracting  20  nanoscale particles or nanocrystals  25  from a nonaqueous colloidal suspension  30  and substantially uniformly depositing  35  the nanoparticles  25  onto the substrate  15 . Typically, the coating or film  10  is less than 1000 nanometers in thickness, but may be thicker. A substrate  15  desired to be coated is typically prepared by first cleaning  40  the substrate  15 , and then, if the substrate  15  is not sufficiently electrically conductive, coating  43  the substrate  15  with a layer of conductive material  45 , such as silver or indium tin oxide (typically used to prepare optical elements, since thin layers of indium tin oxide are substantially optically transparent). 
     A nonaqueous suspension  30  of nanoparticles  25  is then prepared. The liquid suspension medium  50  is typically a polar solvent, such as 2-butanol, 1,2-dichlorobenezene and/or acetone, or the like. Typically, the solvent  50  composition is selected taking into account such properties as its inherent dielectric constant, its Hamaker constant, its miscibility, its viscosity, and the like. More typically, a blend of aprotic polar nonaqueous solvents  55  and protic polar nonaqueous solvents  60  is selected to define the liquid suspension medium  50 . 
     More typically, small amounts of an ionic liquid  65 , such as 1-butyl-1 methylpyrrolinium dis(perifluoromethylsulfonyl)imide, are added to the nonaqueous solvent blend  50  to facilitate deposition of nanoparticle films  10 . A predetermined and measured amount of nanoparticles  25  is then dispersed in the solvent blend  50 . The solvent blend  50  is typically agitated until the nanoparticles  25  are generally evenly and homogeneously dispersed to define a colloidal suspension  30 . A buffer solution may be added to the colloidal suspension  30  to manage the surface charge on the nanoparticles  25 . For example, silicon particles are negatively charged in the pH range between about 6 and about 9 while germanium particles are negatively charged in the pH range from about 3 to about 5. 
     The substrate  15  is then connected to a DC power source  70  to serve as a first electrode  75  while the DC source  70  is connected to the solvent bath  30  through a second electrode or electrode array  80  immersed therein (such as a carbon electrode) to complete an electric circuit and establish an electric field, with the substrate  15  having an opposite charge to that imparted to the suspended particles  25 . The substrate  15  is typically the cathode  75  and the carbon electrode is typically the anode  80 . The electrodes/electrode arrays  75 ,  80  are typically maintained at a distance of between about 0.5 and about 4.0 centimeters apart, depending upon such variables as the desired deposition pattern, the shape of the electrodes  75 ,  80 , the shape of the substrate  15 , and the like; however, under certain circumstances the electrode separation distance may fall outside of the 0.5 to 4.0 centimeter range. The applied voltage is typically between about 3 and about 12 volts, depending on the nanocrystal particle size (typically between about 1 and 1000 nanometers in dimension, more typically between about 2 and about 50 nanometers in diameter). The particles  25  in the suspension  30  will electrophoretically migrate to the substrate  15 , forming a substantially even coating  10  thereupon. 
     The nanoparticles  25  may be of any convenient shape and geometry, and are generally regularly shaped and are typically blocky, and, more typically, generally spherical. Typically, the nanoparticles  25  will be tightly sized, having a relatively narrow particle size distribution (PSD), to yield a coating or film  10  of nanoparticles  25  having a narrow particle size distribution, such as, for example, wherein most of the particles  25  fall in the 3-10 nanometer range. Alternately, the applied voltage, current and/or the pH of the colloidal solution  30  may be varied to yield similar control over the size of the deposited particles  25  when the colloidal solution  30  includes a substantial amount of particles  25  falling outside the target size range. Further, by varying the applied voltage and/or the pH of the medium  30 , multiple layers  90  of nanocrystals may be applied to a substrate  15  in a predetermined, size-specific of graduated order. The deposition process  35  is continued until the desired film thickness is achieved, typically for about 30 seconds to about 5 minutes to yield a deposited layer  90  typically from a few hundred to a few thousand nanometers thick. Typically, the deposition process  35  is conducted under ambient atmosphere; no vacuum is required. 
     Typically, the nanocrystals  25  are of very high purity, typically at least about 99.999 percent pure, more typically at least about 99.9999 percent pure, and still more typically at least about 99.999999 percent pure. The nanocrystals  25  may be monodisperse within +/−10% of the desired diameter and may be single crystal/single grain boundary materials, but are not limited to these types and size dispersions. As illustrated in  FIGS. 4-8 , it is also possible to deposit nanoparticles  25  that have a multilayered or core/shell structure, such as a crystalline core  130  within an amorphous shell  140 , wherein the shell  140  compresses the core  130  to generate stress and maintain strain therein. This effective surface area of the film  10  is a function of the nanocrystalline particle size and shape and is governed by the desired end use and does not change the method of deposition. Likewise, there is no requirement that the electrode or electrode array  80  be of equal or larger size than the conductive substrate  75  that the nanoparticles will be deposited upon. 
     EXAMPLE 1 
     Eighty milligrams of 9-nanometer silicon particles are suspended in 10 milliliters of 2-butanol to yield a colloidal suspension with a concentration of about 8 milligrams silicon nanoparticles/1 milliliter 2-butanol. 10 milliliters of reagent grade acetone is added to the colloidal suspension. 300 microliters of 1-butyl-1methylpyrrolinium dis(perifluoromethylsulfonyl)imide is added to the colloidal suspension. The colloidal suspension is heated to a temperature of about 40 degrees Celsius. A 1 cm×2 cm glass substrate coated with indium tin oxide and having a resistance of about 8 ohms/sq cm is connected to the cathode of a DC power supply and immersed 1 cm into the colloidal suspension. A carbon electrode is connected to the anode of the DC power supply and spaced 1 centimeter from the glass substrate in the suspension. A voltage potential of 4 volts is applied across the electrodes and allowed to remain for 180 seconds while a silicon film having a thickness of between about 500 and about 800 nanometers is deposited on the glass substrate area that was submersed in the colloid solution. 
     EXAMPLE 2 
     Eighty milligrams of highly pure germanium nanocrystal particles were obtained from the Universal Nanotech Corporation. The germanium particles were characterized by an average particle diameter of about 10 nanometers were suspended in a polar protic solvent, such as MeOH, to yield a colloidal suspension. Oleyalamine is added to the colloidal suspension to assist in maintaining the germanium nanoparticles in suspension. The colloidal suspension is typically maintained at a temperature of between about 25 and about 40 degrees Celsius A 1 cm×2 cm glass substrate coated with indium tin oxide and having a resistance of about 8 ohms/sq cm is connected to the cathode of a DC power supply and immersed 1 cm into the colloidal suspension. A carbon electrode is connected to the anode of the DC power supply and spaced 1 centimeter from the glass substrate in the suspension. A voltage potential of between about 1.5 and about 7 volts is applied across the electrodes and allowed to remain for from about 180 seconds to about 5 minutes while a germanium film is deposited on the glass substrate area that was submersed in the colloid solution. 
     Devices made from Group IV nanoparticles  25  benefit from the unique and size-driven physical characteristics of these nanoparticles  25 , sometimes referred to as “quantum dots”. Semiconductors are materials that conduct electricity, but only very poorly. Unlike metals, which have an abundance of free electrons capable of supporting electrical conduction, the electrons in semiconductors are mostly bound. However, some are so loosely bound that they may be excited free of atomic binding by the absorption of energy, such as from an incident photon. Such an event produces an exciton, which is essentially an electron-hole pair, the hole being the net-positively charged lattice site left behind by the freed electron. In most crystals, sufficient excitons may be created such that the freed electrons may be thought of as leaving the valence band and entering the conduction band. The natural physical separation between the electron and its respective hole varies from substance to substance and is called the exciton Bohr radius. In relatively large semiconductor crystals, the exciton Bohr radius is small compared to the dimensions of the crystal and the concept of the conduction band is valid. However, in nanoscale semiconductor crystals or quantum dots, the exciton Bohr radius is on the order of the physical dimension of the crystal or smaller, and the exciton is thus confined. This quantum confinement results in the creation of discrete energy levels and not a continuous band. Exploitation of this phenomenon, such as by coatings of nanoscale semiconductor crystals  25 , can yield such devices as photovoltaic cells ‘tuned’ to specific wavelengths of photons to optimize energy transduction efficiency, rechargeable batteries, photodetectors, flexible video displays or monitors, and the like. 
     Quantum Confined Piezoelectric Effect in Strained Silicon and Germanium Nanoparticles 
     Amplified piezoelectric effects may be observed in quantum-confined nanocrystals  25  such as lead zirconate-titanate, gallium nitride, and indium gallium nitride. In one embodiment of the present novel technology, devices  100  exploit the amplified piezoelectric effects in quantum confined silicon and germanium nanocrystals  25  synthesized in a state of predetermined strain (See  FIGS. 4-15 ). 
     The strain manufactured into the silicon and germanium nanocrystals  25  defining the devices  100  may be further increased through intercalation of additional appropriately sized, small molecules, such as lithium, sodium, or the like. Intercalation is the typically reversible inclusion of a molecule between two other molecules. The novel devices  100  incorporate the intercalation of a small intercalation atom or ion  107 , such as lithium, into the crystal lattice structures of silicon and/or germanium nanocrystals  25  to yield intercalated nanocrystals  110  with internal stresses to further strain the crystal structure and hence increase the energy density, and subsequently the power output capabilities, of the device  100 . 
     The instant internally strained quantum confined silicon and germanium nanocrystals  25  and/or intercalated nanocrystals  110  are deposited onto a conductive substrate  15  into a highly ordered cohesive film  10  via the electrophoretic deposition process as discussed above. During deposition, the nanocrystals  25  self-assemble into a highly ordered structure according to their dipole moments and define a unified Weiss domain throughout the film  10 . Once electrophoretic deposition  35  of the particles  25  is complete, a metal contact  115  is deposited via thermal evaporation or the like over the film  10  to protect the nanoparticle film  10  and establish a pathway for electrons to travel to be used to power an external device. The metal contact  115  is typically a highly electrically conductive metal, such as gold, platinum, silver, copper or the like, and is typically between about 100 nanometers and 400 nanometers thick. 
     EXAMPLE 3 
     A thin film of a mixture of size specific semiconducting nanocrystals  25  was deposited via EPD on ITO coated glass, as described in the above specification and examples. The ultrapure prestrained semiconducting nanocrystals  25  were obtained from the Universal Nanotech Corporation, 1740 Del Range Blvd., PMB 170, Cheyenne, Wyo., 82009. Typically, the nanocrystals  25  are at least about 99.99999 percent pure, more typically at least about 99.999999 percent pure, and still more typically, at least about 99.9999999 percent pure. The substrate  15  and deposited film  10  placed in a low oxygen environment at room temperature and the substrate  15  was then masked to define a desired back contact location. Next, using a thermal evaporator/vacuum coater or like device, the film  10  was placed with the nanocoated side toward the material to be deposited, at a distance of approximately 1-5 cm. A high vacuum environment was formed around the substrate  15  and an appropriate Voltage/Current combination is applied to vaporize the desired metal to be deposited. The vaporized metal was deposited onto the substrate  15  to create a complete layer  115  that is both protective and allows for electrical connections. In general, this deposition process may take from approximately 5 seconds to about 5 minutes, depending on the desired back contact  115  thickness. Once the metal layer  115  was deposited, the vacuum was removed and the film  10  was allowed to return to a typical room temperature environment. The masking was then removed in a low oxygen environment, leaving the desired metal deposition pattern on the film. A voltmeter and/or ammeter was used to confirm that power was being supplied by the newly created quantum energy device (QED). Using standard electrical connection techniques, multiple films  10  may be connected in a series/parallel fashion to yield a device  100  configured to generate the desired voltage/current supply configuration. A QED device  100  was completed and configured to power a desired load. 
     Quantum energy devices  100  as described above in Example 3 may be produced from layered semiconducting nanocrystals  25 , such as silicon nanocrystals. Typically, the nanocrystalline films  10  include a mixture of multiple sizes of specific nanoparticles, ranging from 1 nm to about 500 nm in diameter, although narrow, monomodal size distributors may be desired for specific applications. Such a multimodal particle size distribution (PSD) yields high energy storage and/or power transduction/generation/supply characteristics in the QED device  100 . Typically, for each mode more than 95 percent of the particles fall within 2 nanometers of the mode dimension. In some embodiments, the nanocrystals  10  are provided in a predetermined bimodal or multimodal size distribution, such that the nanocrystals  10  may be deposited to take advantage of more efficient packing density (see  FIG. 13 ). For example, a first sublayer  90  of larger diameter particles  10  (such as 25 nm) may be deposited, and a second sublayer  90  of smaller diameter particles  25  (such as 9 nm) may be deposited thereupon, with the smaller particles  25  preferentially sitting in the interstices defined by the first particles  25 . 
     As illustrated in  FIG. 14 , a film of conducting nanowires  125 , formed from such materials as such as ZnO, MgO or the like, deposited onto the surface of the nanoparticles film  10 , such as through vacuum evaporation or like techniques, may yield effects such as lower series resistance and/or increased electrical conductivity and increased in power discharge capabilities of the QED. This film  125  may be in place of or in addition to the metal backing layer  115 . 
     The typical film thickness of a single layer  10  is in the range of 200 nm-1500 nm. Voltages ranging from 0.1 V-18V in a 1 cm 2  single layer film  10  are achievable and have been verified by measurement. Currents ranging from 10 uA-50 mA are achievable in a single layer film  10  and have been verified by measurement. 
     A QED device  100  has been successfully completed demonstrating individual QED units fabricated using the EPD nanoparticles deposition method, described hereinabove. The individual QED units  100  are wired together, in series or in parallel, to increase the total output voltage or current, respectively. The QED device  100  manufactured by the EPD of nanoparticles  25  has demonstrated the capability to power LEDs and other electronic devices with similar power requirements. Combinations of multiple different sizes of nanoparticles  25  and types of nanoparticles  25  may be used to generate QED devices  100  having specifically tailored and desired output characteristics. Multiple layers  90  of nanoparticles  25  may be utilized, and metal layers  115  may be interspersed or mixed between the nanoparticulate semiconducting layers  90 . Metallic and non-metallic back or front contacts  45 ,  115  may be utilized, depending on the desired QED output. P-type or N-type doped semiconductor (i.e., non-intrinsically doped) nanoparticles  25  may be utilized and/or mixed with intrinsic semiconducting nanoparticles  25 , as desired. 
     Quantum Energy Device (QED) Overview 
     In one embodiment, as shown in  FIG. 14 , the present novel technology relates to a battery  100  that utilizes the unique properties of silicon and germanium nanocrystals  25 . High purity silicon or germanium nanocrystals  25  ranging in size from about 1 nm to about 1000 nm are deposited on to a conductive substrate  45  by use of electrophoretic deposition (EPD). A tightly compacted thin film  10  of the silicon and/or germanium nanocrystals  25  may range in thickness from about 100 nm to about 2000 nm, depending on the desired properties of the film  10 . A conductive metallic back contact  115 , such as aluminum, gold, silver or the like, is applied to the thin film  10  of semiconducting nanocrystals  25  in a thickness range of about 50 nm to about 500 nm. Thermal evaporation, e-beam evaporation, sputter coating, electroplating, or the like may be used to apply the metallic back contact  115 . 
     The silicon and germanium nanocrystals are typically synthesized with a state of stress distributed therein which slightly strains the atomic spacing of the crystal structure. This distorting or straining of the lattice imparts a piezoelectric effect which distorts the electron cloud and gives rise to a voltage potential. Direct current electrical energy may then be utilized to power electrical devices. Individual cells  100  may be wired in series or parallel to supply the desired voltage and amperage needed to power a specific device. 
     EXAMPLE 4 
     A suspension  30  of pre-strained silicon nanocrystals  25  suspended in toluene  50  was obtained from the Universal Nanotech Corporation in a concentration of approximately 100 mg per 100 ml. The suspension  30  includes a mixture of nanocrystal sizes but the majority of nanocrystals  25  were between approximately 10 nm and 150 nm in dimension. The suspension  30  was sonicated to ensure a homogeneous mixture was obtained. Then, approximately 10 ml of homogenized suspension 30 was added to a glass beaker. Approximately 10 ml of acetone was then added to the mixture. 300 microliters of 1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide  65  was also added to the mixture to define an admixture  30 . 
     The admixture  30  was then sonicated again to ensure homogeneity and heated to a temperature of 40 degrees Celsius. A magnetic stir bar was used during heating to facilitate an even temperature in the admixture  30  and to ready the admixture for electrophoretic deposition (EPD) as an EPD bath  30 . 
     A conductive substrate  15  of glass coated with Indium Tin Oxide (ITO)  45  with an average resistance of 8 ohms per square cm and of dimensions of approximately 1 cm wide by 2.5 cm long was cleaned  40  with a spray of pressurized acetone and wiped clean. The ITO glass  15  was then attached to the negative lead (cathode)  75  on the power supply. A high purity carbon electrode  80  was attached to the positive lead (anode) on the power supply  70 . The carbon electrode  80  was inserted into the EPD bath  30 . 
     The ITO coated glass  15  was then inserted into the EPD bath  30  to a depth of approximately 1 cm with the conductive side facing the carbon electrode  80  and separated by a distance of approximately 1 cm. The power supply  70  was energized and approximately 4 volts and minimal/negligible current was applied for approximately 3 minutes. During the 3 minutes the nanocrystals  25  were deposited onto the conductive substrate  15  and were visually observed as the film  10  grew thicker and become more opaque. The power supply  70  was deenergized and the conductive substrate  15  was removed from the EPD bath  30 . 
     After silicon nanocrystal  25  application, lithium was deposited on to the film through electroplating of lithium acetate dissolved in a solution of dimethylacetamide (DMA). The silicon nanocrystal film  10  was then submerged into the solution for electrophoretic deposition of lithium. Lithium ions  107  were intercalated into the silicon crystal structures  110  during EPD to define a device  100  having increased charge density and enhanced recharging capabilities. The device  100  was then set out to dry in a low oxygen environment at elevated temperature (about 110 degrees Celsius). It should be noted that while convenient to increase drying rate, heat is not essential. 
     Within 3 hours, a metallic back contact  115  was applied to prevent oxidation of the silicon thin film  10 . A high purity aluminum metallic back contact  115  was applied using a thermal evaporator to a thickness of approximately 200 nm. Masking tape, metal screens, and glass were used to control the location of the metallic back  115  contact and to prevent the aluminum layer  115  from shorting to the ITO coated glass  15 . 
     After the aluminum layer  115  was applied, the QED cell  100  was complete and is ready for wiring to a desired electrical device. Great care was taken to not touch the cell area with the silicon nanocrystals film  10  applied to prevent any shorting of the cell  100 . A series and parallel circuit was then created using multiple cells  100  that were produced in the same manner. Through this process, an array of QEDs  100  were wired to generate over 3.7 volts and 50 mA. This array  100  was then connected to a TFT display screen and the device functioned as normal with the QED device  100  supplying the electrical energy. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Typical Properties of Silicon Film of 1 square cm 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Volts 
                 1.5 
               
               
                   
                 Amps 
                 0.005 
               
               
                   
                 Watts 
                 0.0075 
               
               
                   
                 Battery Life (hrs) 
                 48 
               
               
                   
                 Watt-Hours 
                 0.36 
               
               
                   
                 Kilowatt-Hours 
                 0.00036 
               
               
                   
                 Megajoules (MJ) 
                 0.001296 
               
               
                   
                 Grams of Si 
                 0.00018632 
               
               
                   
                 Kilograms of Si 
                 1.8632E−07 
               
               
                   
                 MJ/Kg 
                 6955.8 
               
               
                   
                 Grams/Watt-Hour 
                 0.000518 
               
               
                   
                   
               
             
          
         
       
     
                                               Energy Density Comparison                                    Alkaline   0.59   MJ/Kg           Li-ion rechargeable   0.46   MJ/Kg           Zinc-air   1.59   MJ/Kg           NiMH   0.36   MJ/Kg                        
The energy density observed from the arrayed QED device  100  was about 7000 MJ/Kg, several orders of magnitude higher than that of an alkaline cell, a lithium-ion battery, and the like.
 
     Another embodiment device  100  is illustrated in  FIG. 15 . The device  100  is similar to that described above regarding  FIG. 14 , but with the addition of an electrolyte  165  in contact with the intercalated nanocrystals  25  making up the film  10 . The electrolyte  165  composition is typically matched to the intercalation agent  107  composition (i.e., a lithium salt electrolyte for use with lithium electrodes and/or lithium intercalation to yield a lithium ion battery cell), such that the electrolyte facilitates ionic conduction and allow the device  100  to function as a voltage source for rechargeable lithium-ion batteries. 
     This process may be modified in various ways to benefit mass production and to tailor specific electrical properties. It is not possible to cover all permutations and therefore it is understood that this novel technology is not limited to the examples detailed above. 
     While the novel technology has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It is understood that the embodiments have been shown and described in the foregoing specification in satisfaction of the best mode and enablement requirements. It is understood that one of ordinary skill in the art could readily make a nigh-infinite number of insubstantial changes and modifications to the above-described embodiments and that it would be impractical to attempt to describe all such embodiment variations in the present specification. Accordingly, it is understood that all changes and modifications that come within the spirit of the novel technology are desired to be protected.