Polymers containing silicon nanoparticles dispersed within polymer pieces coated with silicon nanoparticles

Abstract

(a) providing a piece of polymer host matrix material coated with silicon nanoparticles; (b) softening the piece of polymer host matrix material coated with silicon nanoparticles to form a softened piece of polymer host matrix material; and (c) blending the softened piece of polymer host matrix material together with silicon nanoparticles on the surface of the softened piece of polymer host matrix material to form a single mass of polymer host matrix material in which silicon nanoparticles are dispersed, thereby preparing a polymer host matrix material in which silicon nanoparticles are dispersed.

Description

[Technical Field]

[0001] The present invention relates to a polymer material in which silicon nanoparticles are dispersed, and to a process for producing such a polymer material from polymer pieces coated with silicon nanoparticles. [Background technology]

[0002] Introduction The advent of nanotechnology is bringing about a paradigm shift in many technological fields because the properties of many materials change at the nanoscale. For example, reducing certain structural dimensions to the nanoscale can increase the ratio of surface area to volume, thus causing changes in the electrical, magnetic, reactive, chemical, structural, and thermal properties of the material. Nanomaterials have already been found in commercial applications and will be present in a wide range of technologies in the coming decades, including computers, photovoltaics, optoelectronics, pharmaceuticals, building materials, military applications, and many others.

[0003] Silicon nanoparticles are one desirable type of nanoparticle. A key characteristic of small silicon nanoparticles, with an average size of less than 10 nanometers (nm), is that these silicon nanoparticles are photoluminescent in visible light when stimulated by lower wavelength sources (UV). This is thought to be caused by a quantum confinement effect that occurs when the nanoparticle diameter is smaller than the exciton diameter, resulting in bandgap bending (i.e., an increase in the gap). Researchers have shown how the bandgap energy (in electron volts) of nanoparticles changes as a function of the nanoparticle diameter.

[0004] While silicon is an indirect bandgap semiconductor in bulk, silicon nanoparticles with an average size of less than 10 nm can rival direct bandgap materials, made possible by exciton interfacial trapping. Direct bandgap materials can be used in optoelectronic applications as silicon quantum dot materials. Silicon quantum dots are particularly desirable over other quantum dot materials because they do not require environmentally unfriendly components such as lead, selenide, cadmium, indium, arsenides, or even germanium. Another interesting property of nanomaterials is the decrease in melting point, which follows surface phonon instability theory. Researchers have shown that the melting point of nanomaterials formed from nanoparticles changes as a function of the nanoparticle diameter.

[0005] There are applications that benefit from having silicon nanoparticles dispersed within compositions often known as "host matrices," such as polymers. However, directly dispersing nanoparticles in a host matrix without experiencing aggregation of silicon nanoparticles can be challenging. Some prior art attempts describe dispersing nanoparticles in monomers and then polymerizing the monomers to obtain a polymer host matrix in which the nanoparticles are dispersed. However, this requires the compounder to adapt to handling the monomers and carrying out the polymerization. It is desirable to identify an efficient method for directly dispersing silicon nanoparticles in a polymer host matrix material without the need to handle monomers and perform polymerization procedures to disperse nanoparticles in the polymer matrix. [Overview of the project]

[0006] The present invention provides an efficient method for directly dispersing silicon nanoparticles in a polymer host matrix without the need to disperse them in a monomer and then polymerize them into a polymer matrix material. The method can also provide a means for achieving concentration of silicon nanoparticles within a polymer matrix material using polymers and silicon nanoparticles with different flow rates.

[0007] This invention is the result of finding that silicon nanoparticles are thermally and physically stable enough that they can not only be deposited onto pieces of polymer host matrix material during the production of silicon nanoparticles, but also that pieces coated with silicon nanoparticles of the polymer host matrix material can be melt-blended and then hot-pressed to form a polymer host matrix in which silicon nanoparticles are dispersed throughout the polymer host matrix. Even when the silicon nanoparticles are silicon quantum dots, they withstand the temperatures of melt-blending and hot-pressing to produce a polymer composition in which silicon quantum dots are dispersed. Even more surprisingly, the flow of the thermoplastic polymer host matrix containing dispersed silicon nanoparticles can undergo different flow between the silicon nanoparticles and the thermoplastic polymer host matrix, resulting in a concentration effect of silicon nanoparticles by inducing the flow of the thermoplastic polymer host matrix material. This result is thought to be the result of a phenomenon in which the silicon nanoparticles flow more slowly than the thermoplastic polymer host matrix, resulting in a concentration effect of silicon nanoparticles in the thermoplastic polymer host matrix that avoids aggregation of silicon nanoparticles. This concentration procedure makes it possible to obtain a higher concentration of silicon nanoparticles in the thermoplastic polymer host matrix than is possible by directly mixing the nanoparticles into the thermoplastic polymer host matrix without aggregation.

[0008] In a first embodiment, the present invention relates to a method for preparing a polymer host matrix material in which silicon nanoparticles are dispersed, comprising: (a) providing a piece of polymer host matrix material coated with silicon nanoparticles; (b) softening the piece of polymer host matrix material coated with silicon nanoparticles to form a softened piece of polymer host matrix material; and (c) blending the softened piece of polymer host matrix material together with silicon nanoparticles on the surface of the softened piece of polymer host matrix material to form a single mass of polymer host matrix material in which silicon nanoparticles are dispersed.

[0009] The process of the present invention is useful for dispersing silicon nanoparticles in a polymer host matrix. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram illustrating the VHFLPP settings used in the preparation of the examples described herein is provided as an example. [Modes for carrying out the invention]

[0011] Products identified by trade names refer to compositions available under those trade names as of the priority date of this document.

[0012] "Multiple" means two or more. "And / or" means "and, or as an alternative." All ranges include the endpoint unless otherwise specified.

[0013] "Cx~Cy", "C x ~C y "C x~y " refers to a composition having interchangeable carbon atoms in the range of x to y.

[0014] "Silicon nanoparticles" refer to silicon-based particles having an average particle size of less than 1 micrometer, typically 100 nanometers (nm) or less, while also having an average particle size of 1 nm or greater. Dynamic light scattering or transmission electron microscopy image analysis are common methods for determining the average particle size of silicon nanoparticles. Silicon nanoparticles include silicon quantum dots.

[0015] "Silicon-based" refers to a composition containing silicon. Silicon-based materials generally contain 40 percent (%) or more of silicon atoms or a combination of silicon atoms and oxygen atoms relative to the total atoms in the material, and may contain 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or even 100% of silicon atoms or a combination of silicon atoms and oxygen atoms.

[0016] "Silicon quantum dots" refer to silicon nanoparticles having a crystalline silicon structure that exhibit photoluminescence when exposed to light. Typically, silicon quantum dots have an average particle size in the range of 1 to 10 nanometers, preferably 1 to 6 nanometers, and more preferably 1 to 5 nanometers. Silicon quantum dots are characterized by the fact that they emit light when exposed to light having wavelengths in the 300 to 477 nanometer wavelength range, corresponding to blue light and ultraviolet light.

[0017] The present invention relates to a process for preparing a polymer host matrix material in which silicon nanoparticles, preferably silicon quantum dots, are dispersed. The polymer host matrix material is a softenable material, meaning that it can be softened by heating and / or the addition of a solvent and hardened by cooling and / or the removal of the solvent. Preferably, the polymer host matrix material is a polymer, preferably a thermoplastic polymer. The polymer host matrix material may be crystalline, semicrystalline, or amorphous. Examples of suitable polymers that may be polymer host matrix materials include homopolymers and copolymers. Examples of suitable polymers that may be polymer host matrix materials include any one polymer or any combination of one or more polymers selected from the group consisting of polyethylene, polypropylene, polybutadiene, poly(methyl methacrylate), polystyrene, polyisoprene, poly(vinyl butyral), poly(lactic acid), and poly(amide). Polyethylene includes variations of polyethylene such as low-density polyethylene, linear low-density polyethylene, and high-density polyethylene.

[0018] The process of the present invention includes providing a piece of polymer host matrix material coated with silicon nanoparticles, softening the piece of polymer host matrix material to form a softened piece of polymer host matrix material, and then blending the softened piece of polymer host matrix material together with silicon nanoparticles on the surface of the softened piece of polymer host matrix material to form a single mass of polymer host matrix material in which silicon nanoparticles are dispersed. The “piece” in relation to the piece of polymer host matrix material may be any form, such as one or any combination of one or more pieces of pellets, powders, granules, flakes, plates, chips, blocks, and sheets or films.

[0019] In the broadest scope of the present invention, providing a piece of polymer host matrix material coated with silicon nanoparticles can be achieved in any manner. Exemplary methods for providing a piece of polymer host matrix material coated with silicon nanoparticles include (1) spray coating a piece of polymer host matrix material with silicon nanoparticles, (2) directly depositing silicon nanoparticles onto a piece of host matrix material when preparing silicon nanoparticles, and (3) depositing silicon nanoparticles in a capture fluid containing a piece of polymer host matrix material when preparing silicon nanoparticles. Each of these methods preferably uses a very high frequency low pressure plasma (VHFLPP) process to prepare the silicon nanoparticles.

[0020] V HFLPP process The VHFLPP process is a generally known process for producing nanoparticles, and in this application, the silicon nanoparticles include silicon quantum dots. The VHFLPP process provides better control over particle size and size distribution than other processes for producing nanoparticles. Examples of the VHFLPP process are taught in the prior art, including U.S. Patent Application Publication 2013 / 0189446, U.S. Patent Application Publication 2012 / 0326089, and International Publication 2020 / 205850. A basic description of the VHFLPP process is as follows:

[0021] The VHFLPP process uses a gas stream containing at least one nanoparticle precursor flowing through a quartz tube at a pressure of less than 13,333 Pascals (Pa). To produce silicon nanoparticles, the nanoparticle precursor is typically a silicon-containing material selected from the group consisting of silane, disilane, halogen-substituted silane, halogen-substituted disilane, C1-C4 alkylsilane, C1-C4 alkyldisilane, and mixtures of any combination thereof, or contains those silicon-containing materials. The gas stream can contain additional precursors (dopants), typically containing components or any combination of components selected from the group consisting of halogen, germanium, boron, phosphorus, and nitrogen. The combined concentration of the nanoparticle precursor and dopant in the gas stream is typically in the range of 0.1 to 50 volume percent (vol%) with respect to the gas stream composition. The remainder of the gas stream is mainly one or a combination of two or more of inert gases such as argon (Ar), helium (He), neon (Ne), krypton (Kr), xenon (Xe), and radon (Rn).

[0022] There are two ring electrodes concentrically outside the quartz tube, which are typically copper ring electrodes separated from each other with one ring electrode being "upstream" (with respect to the gas stream) relative to the other ring electrode. By supplying power to the upstream ring electrode using a radio frequency source and grounding the other ring electrode simultaneously, a plasma is generated inside the quartz tube. The radio frequency is at a very high frequency (typically in the range of 30 to 500 megahertz) and is coupled to power typically in the range of 80 to 1000 watts.

[0023] When flowing through the plasma, the nanoparticle precursor decomposes, nucleates, and grows into nanoparticles. The pressure of the plasma is 6666 Pascals (Pa) or less, preferably 667 Pa or less, and at the same time, is typically 133 Pa or more.

[0024] The nanoparticles continue to flow through the gas stream, passing through the orifice and exiting the quartz tube into the collection chamber. While the gas stream is flowing, the collection chamber is at a pressure of less than 13.33 Pascals (Pa). When the gas stream is not flowing, the collection chamber is typically at 6.67 × 10⁻⁶ -5 This is pressure in Pa.

[0025] The VHFLPP process can be performed as a continuous or pulsed process. A continuous VHFLPP process uses a constant and continuous radio frequency on the upstream ring electrode. In contrast, a pulsed VHFLPP process uses an amplitude-modulated very high frequency (VHF) radio frequency signal applied to the upstream ring electrode. The amplitude-modulated signal typically operates at 1–50 kHz as a square wave function multiplied by a continuous VHF sinusoidal waveform. The advantage of the pulsed process is that the pulse energy is used to control the size of the resulting nanoparticles by controlling the residence time the nanoparticle precursor is exposed to the high-power plasma as it passes through the VHF glow discharge. In a continuous VHF plasma process (unmodulated), the nanoparticle size can be controlled by the concentration of the nanoparticle precursor, the silicon concentration in the case of silicon nanoparticles, and the residence time of the precursor through the VHF plasma.

[0026] Spray coating method In a spray coating method for providing pieces of polymer host matrix material, it is desirable to collect nanoparticles in a trapping fluid, transfer them to a solvent, and then spray coat them onto the pieces of polymer host matrix material.

[0027] When collecting silicon nanoparticles in a capture fluid, the capture fluid is placed in the collection chamber of the VHFLPP process in the flow path of the nanoparticle-containing gas stream. The distance between the surface of the capture fluid and the orifice of the quartz tube is preferably in the range of 5 to 50 orifice diameter. The gas stream containing nanoparticles collides with the surface of the capture fluid, thereby introducing the nanoparticles into the capture fluid from which they are collected. Typically, to aid in the dispersion of nanoparticles in the capture fluid, the capture fluid is agitated during nanoparticle collection (e.g., by stirring or ultrasonic agitation) and / or the reservoir containing the capture fluid is rotated during nanoparticle collection. After capture is complete, it is also useful to ultrasonically treat the capture fluid containing the nanoparticles to promote nanoparticle dispersion.

[0028] The capture fluid should have a sufficiently low vapor pressure so that it remains largely undamaged in the reservoir within the collection chamber during the VHFLPP process. The capture fluid is preferably non-aqueous. Examples of suitable capture fluids include mineral oils, silicone oils (e.g., polydimethylsiloxane (PDMS), phenylmethyl-dimethylcyclosiloxane, tetramethyltetraphenyltrisiloxane, and pentaphenyltrimethyltrisiloxane), fluorocarbons, and alkylene oxide oils. The capture fluid may also be a blend of two or more fluids. Further desirable properties and examples of suitable capture fluids are taught in paragraphs

[0070] to

[0077] of International Publication No. 2020 / 205850, which are incorporated herein by reference as preferably applicable to the capture fluids of the present invention.

[0029] The capture fluid may contain additives dissolved or dispersed therein. Desired additives include surface modifiers (functionalizers) that adhere to the surface of nanoparticles when they are collected. Surface modifiers can act as compatibilizers to make nanoparticles more compatible with the capture fluid or any other medium that needs to be combined with the nanoparticles, can make the surface of the nanoparticles more reactive for further chemical reactions, or can impart both compatibility and reactivity. Examples of additives that may be included in the capture fluid include hydrocarbons (such as 1-alkenes) to help disperse nanoparticles in hydrophobic media, oligoglycols (such as allyl ethers) to help disperse nanoparticles in hydrophilic media, terminal olefins containing functional groups such as alcohols, carboxylates, and amines, as well as protected versions thereof for post-passivation conversion and extraction, and fluorocarbons having terminal olefins to help disperse nanoparticles in fluoropolymers.

[0030] In the VHFLPP process, the captured fluid can be recycled or reused. That is, nanoparticles can be collected in the same captured fluid for multiple VHFLPP processes. Typically, nanoparticles are isolated from the captured fluid before reuse, but this is not necessary. For example, nanoparticles can be collected in the captured fluid, passivated, and then isolated from the captured fluid (e.g., by filtration or centrifugation). The remaining captured fluid can then be used in subsequent VHFLPP processes.

[0031] After collecting silicon nanoparticles in a trapping fluid, it is desirable to passivate them, especially silicon nanoparticles, to provide stability against exposure to air. Silicon nanoparticles are readily passivated in the trapping fluid by exposing the trapping fluid containing the silicon nanoparticles to a relatively humid atmosphere at a temperature typically above 25°C for a certain period of time. Moisture slowly permeates the trapping fluid and reacts to form a passivated oxide layer on the silicon nanoparticles. For example, one method of passivating silicon nanoparticles in a trapping fluid is to expose the nanoparticles and the trapping fluid to an atmosphere, typically 12 to 72 hours, and may be longer than 72 hours, at a temperature of 23°C or higher, typically 50°C or higher, 60°C or higher, 65°C or higher, and even 70°C or higher, while typically 80°C or lower, or 70°C or lower, even 65°C or lower, and a relative humidity of 85%. In some examples, this period may be 168 hours or longer. Longer periods can result in a higher degree of oxidation of the silicon nanoparticle surface, especially in fluids with low oxygen and moisture permeability.

[0032] Typically, silicon nanoparticles are isolated from the captured fluid by centrifugation followed by fluid removal and / or filtration. The silicon nanoparticles are then dispersed in a sprayable fluid, such as a solvent (e.g., toluene). The dispersion of silicon nanoparticles in the sprayable fluid is then spray-coated onto pieces of polymer host matrix material, which are then dried. The resulting polymer hot material pieces are coated with silicon nanoparticles.

[0033] Direct deposition method When silicon nanoparticles are collected directly onto a substrate (e.g., a piece of polymer host matrix material), the substrate is placed in a collection chamber within a channel of a gas flow containing the nanoparticles. When the nanoparticles come into contact with the substrate, they accumulate on the surface of the substrate. It is desirable to move the substrate as the gas flow containing the nanoparticles impacts it, so that the nanoparticles are distributed across the surface of the substrate rather than clumping together. For example, the substrate may be in an open container that rotates or moves in parallel under the gas flow containing the nanoparticles in the collection chamber. The resulting substrate (e.g., a piece of polymer host matrix material) is then coated with silicon nanoparticles.

[0034] In particular, when silicon nanoparticles are silicon quantum dots, it is desirable to passivate the silicon nanoparticles on the substrate before exposure to air. One method of passivating silicon nanoparticles is to immerse host matrix particles coated with silicon nanoparticles in a protective fluid while under vacuum or a dry inert atmosphere, and then expose the fluid to air in a controlled manner to control the rate at which oxygen and moisture reach the silicon nanoparticles so that a protective oxide layer grows on the silicon nanoparticles without experiencing catastrophic thermal decomposition. Suitable protective fluids include a capture fluid.

[0035] One method for passivating a substrate coated with silicon nanoparticles in a protective fluid such as a trapping fluid is to expose the nanoparticles and the protective fluid to an atmosphere, preferably air, at a temperature of 23°C or higher, typically 50°C or higher, 60°C or higher, 65°C or higher, and even 70°C or higher, while simultaneously typically 80°C or lower, or 70°C or lower, even 65°C or lower, and a relative humidity of 85%, for a certain period of time, typically 12 to 72 hours, and may be longer than 72 hours. In some examples, this period may be 168 hours or longer. Longer periods can result in a higher degree of oxidation of the silicon nanoparticle surface, especially in protective fluids with low oxygen and moisture permeability.

[0036] Deposition in the trapping fluid method The most desirable method for providing pieces of polymer host material coated with silicon nanoparticles is to coat the pieces directly in a capturing fluid while collecting silicon nanoparticles in the capturing fluid. This method captures silicon nanoparticles in the capturing fluid, as described for the spray coating method above. However, the capturing fluid has pieces of polymer host material that are at least partially (preferably fully) immersed in the capturing fluid while capturing silicon nanoparticles. In this method, silicon nanoparticles tend to enter the capturing fluid, disperse, and then coat the pieces of polymer host material in the capturing fluid. This method typically results in a more uniform coating of the pieces of polymer host material than can be achieved by direct deposition, because the capturing fluid acts as a dispersant for the silicon nanoparticles before they come into contact with the pieces of polymer host material. To help disperse the nanoparticles throughout the capturing fluid, it is desirable to have the capturing fluid in a container while collecting the nanoparticles and to move the container. For example, a container containing particles of polymer host matrix material is placed in a collection chamber, and the container is rotated or translated as a gaseous flow containing nanoparticles flows into the capturing fluid.

[0037] The capture fluid may contain additives dissolved or dispersed therein. Desired additives include surface modifiers (functionalizers) that adhere to the surface of nanoparticles when they are collected. Surface modifiers can act as compatibilizers to make nanoparticles more compatible with the capture fluid or any other medium that needs to be combined with the nanoparticles, or they can make the surface of the nanoparticles more reactive for further chemical reactions, or they can impart both compatibility and reactivity. Examples of additives that may be included in the capture fluid include hydrocarbons (such as 1-alkenes) to help disperse nanoparticles in hydrophobic media, oligoglycols (such as allyl ethers) to help disperse nanoparticles in hydrophilic media, terminal olefins containing functional groups such as alcohols, carboxylates, and amines, as well as protected versions thereof for post-passivation conversion and extraction, and fluorocarbons having terminal olefins to help disperse nanoparticles in fluoropolymers.

[0038] It is desirable to passivate silicon nanoparticles coated on a polymer host material before exposure to air. Most preferably, the silicon nanoparticles are passivated while in a trapping fluid. Silicon nanoparticles are readily passivated in a trapping fluid by exposing the fluid containing the silicon nanoparticles to a relatively humid atmosphere at a temperature typically above 25°C for a certain period of time. Moisture slowly permeates the trapping fluid and reacts to form a passivated oxide layer on the silicon nanoparticles. For example, one method of passivating silicon nanoparticles in a trapping fluid is to expose the nanoparticles and the trapping fluid to an atmosphere, preferably air, at a temperature of 23°C or higher, typically 50°C or higher, 60°C or higher, 65°C or higher, and even 70°C or higher, while simultaneously typically 80°C or lower, or 70°C or lower, even 65°C or lower, and a relative humidity of 85%, for a certain period typically 12 to 72 hours, and possibly longer than 72 hours. In some examples, this period may be 168 hours or longer. Longer exposure times can lead to a higher degree of oxidation of the silicon nanoparticle surface, especially in fluids with low oxygen and moisture permeability.

[0039] Pieces coated with silicon nanoparticles of polymer host matrix material can be isolated from the captured fluid, for example, by filtration. Rinsing with a solvent may be desirable to remove any remaining captured fluid. The captured fluid can be reused if desired.

[0040] Softened pieces of polymer host matrix material coated with silicon nanoparticles can be produced by any means within the broadest scope of the present invention. For example, softening can occur by heating and / or adding a solvent to the polymer host matrix material coated with silicon nanoparticles. The polymer host matrix material should be softened sufficiently to allow the pieces of host matrix material to be blended together to form a single mass of polymer host matrix material. Blending can be done, for example, by hand using a stirrer or spatula, using a mechanical mixer, or by directing through an extruder. When the softened pieces of polymer host matrix material are mixed, a single mass of polymer host matrix material in which silicon nanoparticles are dispersed is formed.

[0041] A single mass of host matrix material in which silicon nanoparticles are dispersed can be further processed. For example, the host matrix material can be further softened to form a fluid composition, which can then be made flowable or circulated without mixing. Surprisingly, silicon nanoparticles dispersed within the host matrix material tend to flow at a different rate than the host matrix material, thereby resulting in a concentration effect of silicon nanoparticles within the host matrix material. Typically, silicon nanoparticles flow more slowly than the host matrix material, resulting in a higher concentration in the host matrix material where the host matrix material flows without carrying the silicon nanoparticles with it at a proportional concentration. Alternatively or additionally, a single mass of polymer host matrix material in which silicon nanoparticles are dispersed can be formed into a film of the host matrix material by compressing the softened single mass of the polymer host matrix material in which silicon nanoparticles are dispersed. Such compression for forming the film can be done in a batch process in a press or in a continuous manner, such as by passing it through rollers. Such films can be particularly useful as agricultural films if the silicon nanoparticles are silicon quantum dots that absorb light of wavelengths less suitable for agriculture (e.g., light with wavelengths less than 400 nanometers) and emit light of wavelengths more suitable for agriculture. Light of wavelengths suitable for agriculture is typically in the range of 600 to 750 nanometers. The resulting agricultural film then functions to convert light of wavelengths that are less useful or even harmful into light of wavelengths that are useful. For example, light of wavelengths that are less useful or harmful may be ultraviolet light that damages plants, while wavelengths of light that are more useful may be blue, green, or red wavelengths that plants can use for photosynthesis. Agricultural films are useful as covers for plants or even as covers for greenhouses.

[0042] A single mass of host matrix material in which silicon nanoparticles are dispersed can, or alternatively, be extruded to form various types of polymer compositions containing pellets of host matrix material in which silicon nanoparticles are dispersed. [Examples]

[0043] material Table 1 lists the components used in the preparation of the following samples.

[0044] [Table 1]

[0045] SentryGlas is a registered trademark of Kuraray Amberica.

[0046] Samples using deposition of polymer host matrix material on particles in a trapping fluid Preparation of SiQD-coated LDPE particles The following steps refer to Figure 1 for a general image of the components of the VHFLP process used to prepare silicon quantum dots (SiQDs).

[0047] In the glove box 1, 8 grams (g) of mineral oil and 7.1 g of LDPE pellets are placed in the open container ("capture fluid reservoir") 6, and then the capture fluid reservoir is transferred to the load lock 2 through the gate valve 2a. The load lock 2 is evacuated using a roughing pump until the pressure is less than 2.67 Pa. The main collection chamber 4 is evacuated using a high vacuum pump 11 (a turbomolecular pump with a pumping speed of 600 liters / second (an Ebara S50 semiconductor pump with a pumping speed of 5,000 liters / minute) assisted by the roughing pump) to 6.67 × 10⁻¹⁶ -5Evaporate until the pressure is less than Pa. Use the transfer arm 2c to move the capture fluid reservoir 6 through the gate valve 3 into the main collection chamber 4 and place it on the capture fluid reservoir holder 7. Position the capture fluid reservoir 6 6.5 cm below the orifice 5b using the capture fluid reservoir holder 7. Close the gate valve 3 and open the main collection chamber 4 to 6.67 × 10 -5 The fluid is exhausted to a pressure of Pa. The fluid capture reservoir holder 7, and consequently the fluid capture reservoir 6, are rotated at a speed of 12 revolutions per minute.

[0048] A gas flow of 35 standard cubic centimeters per minute (SCCM) of nanoparticle precursor and 55 SCCM of Ar carrier gas is supplied to the inlet end 5a and exits through the dielectric discharge tube 5 to the main collection chamber 4 via the discharge tube orifice 5b. Plasma 9 is generated in the discharge tube 5 by applying an AC sinusoidal bias to electrodes 8a and 8b of the double copper electrode 8. The sinusoidal bias is generated using a Tektronix AFG3252 function generator and an Electronic and Innovation 3200L Class A radio frequency amplifier connected to the electrodes. The sinusoidal bias between the electrodes generates a capacitively coupled ultra-high frequency (90-500 megahertz) plasma in the dielectric discharge tube. The frequency source is adjusted to provide the maximum power coupled to the plasma while minimizing the sinusoidal drive amplitude. The coupled power density of the plasma is 130 watts / cm² (W / cm²). 2 It is larger than ). Silicon nanoparticles are formed in the plasma 9, pass through the discharge tube orifice 5b in the main collection chamber 4, exit the dielectric discharge tube, enter the capture fluid in the capture fluid reservoir, and coat the LDPE pellets in the capture fluid.

[0049] The generation and collection of silicon nanoparticles in this manner is continued for 70 minutes, after which the power to electrodes 8a and 8b is switched off. The gate valve 3 is opened, and the capture fluid reservoir is returned to the load lock 2 using the transfer arm 2c. The capture fluid reservoir is transferred to the glove box, and the contents of the capture fluid reservoir are poured into a glass jar. The glass jar is transferred to a humidity chamber (Associated Environmental Systems, Model LH-10) maintained at 60°C and 85% relative humidity. The uncapped glass jar is left in the humidity chamber for 7 days to slowly passivate the silicon nanoparticles by forming an oxide coating.

[0050] The silicon nanoparticle-coated LDPE pellets are isolated from the capture fluid by transferring the contents of the capture fluid reservoir 6 to a syringe (COVIDIENT Luer lock sterile syringe, 60 cubic centimeters, Grainger catalog number 9VZF7) fitted with a filter (polytetrafluoroethylene syringe filter, 0.22 micrometer CELLTREAT brand filter). The syringe plunger is pushed down to drive the capture fluid out of the syringe through the filter while holding the silicon nanoparticle-coated LPDE pellets inside the syringe. Toluene is added to the syringe containing the silicon nanoparticle-coated LPDE pellets to rinse the pellets, and then the toluene is squeezed out of the syringe through the filter. Rinse again with toluene in the same manner. The resulting silicon nanoparticle-coated LPDE pellets are dried in an oven at 60°C. LPDE pellets coated with dried silicon nanoparticles exhibit visible photoluminescence when exposed to ultraviolet light (365 nanometer wavelength from Waveform Lighting's real UV LED flashlight with BLACKOUT® Filter Technology, catalog number 7023), indicating that the silicon nanoparticles are silicon quantum dots.

[0051] Sample 1: LDPE film with dispersed silicon quantum dots LDPE pellets coated with 3-4 grams of silicon nanoparticles are placed between two PTFE sheets, and the resulting PTFE sheets and silicon nanoparticle-coated LDPE pellets are placed in a vacuum bag (FoodSaver vacuum Seal Rolls, part number 191396). The vacuum bag is evacuated (using FoodSaver part number FSSMSL0160-000), and then, while still inside the vacuum bag, the two PTFE sheets are compressed at 150°C for 30 minutes at a pressure range of 4-6 on the clamshell heat press's pressure scale against the silicon nanoparticle-coated LDPE pellets using a clamshell heat press (Geo Knight & Co., model DK16) to create an LDPE film between the PTFE sheets. The LDPE film and PTFE sheets are removed from the vacuum bag. The LDPE film emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots dispersed within it.

[0052] Sample 2: LDPE monoliths from LDPE pellets coated with silicon nanoparticles mixed with uncoated LDPE pellets. To form a single molten polymer mixture, LDPE pellets coated with silicon nanoparticles are hand-blended with LDPE pellets not coated with silicon nanoparticles, while heating them to a temperature sufficient to soften and flow the LDPE pellets. The single molten polymer mixture is cooled to form an LDPE monolith. The LDPE monolith emits light when exposed to ultraviolet light (365 nanometer wavelength from Waveform Lighting's BLACKOUT® Filter Technology real UV LED flashlight, catalog number 7023), indicating the presence of silicon quantum dots dispersed within it.

[0053] Samples using direct deposition onto particles of polymer host matrix materials Inside the glove box, 1 gram of LDPE pellets are placed in an open container ("capture fluid reservoir") 6 that contains no capture fluid, and then the capture fluid reservoir is transferred to the load lock 2. The load lock 2 is evacuated using a rough pump until the pressure is less than 2.67 Pa. The main collection chamber 4 is evacuated to a pressure of less than 6.67×10 -5 Pa using a high vacuum pump 11 (a turbo molecular pump (Ebara S50 semiconductor pump with a pumping speed of 5,000 liters / minute) with a pumping speed of 600 liters / second assisted by a rough pump). The transfer arm 2c is used to transfer the capture fluid reservoir through the gate valve 3 into the main collection chamber 4 and place it on the capture fluid reservoir holder 7. The capture fluid reservoir is placed 6.5 centimeters below the orifice 5b using the capture fluid reservoir holder 7. The gate valve 3 is closed and the main capture chamber 4 is evacuated to a pressure of 6.67×10 -5 Pa. The capture fluid reservoir holder 7, and thus the capture fluid reservoir, is rotated at a speed of 12 revolutions per minute.

[0054] A gas flow of 35 SCCM of nanoparticle precursor, 50 SCCM of Ar carrier gas, 3 SCCM of H2 carrier gas, and 百分之0.3 SCCM of chlorine dopant is supplied to the inlet end 5a and exits from the discharge tube orifice 5b into the main collection chamber 4 through the dielectric discharge tube 5. A plasma 9 is generated in the discharge tube 5 by applying an alternating current sine wave bias to the electrodes 8a and 8b of the double copper electrode 8. A sine wave bias is generated using a Tektronix AFG3252 function generator and an Electronic and Innovation 3200L Class A radio frequency amplifier connected to the electrodes. The sine wave bias between the electrodes generates a very high frequency (frequency of 90 - 500 megahertz) capacitively coupled plasma inside the dielectric discharge tube. The frequency source is adjusted to provide the maximum power coupled to the plasma while minimizing the driving amplitude of the sine wave. The coupled power density of the plasma is 130 watts per square centimeter (W / cm 2It is larger than ). Silicon nanoparticles are formed in the plasma 9, pass through the discharge tube orifice 5b in the main collection chamber 4, exit the dielectric discharge tube, reach the LDPE pellet in the capture fluid reservoir, and coat the LDPE pellet with silicon nanoparticles.

[0055] The generation and collection of silicon nanoparticles is continued in this manner for 45 minutes, after which the power to electrodes 8a and 8b is switched off. The gate valve 3 is opened, and the capture fluid reservoir is returned to the load lock 2 using the transfer arm 2c. The capture fluid reservoir is transferred to the glove box, and 12 g of mineral oil is added to the capture fluid reservoir. The contents of the capture fluid reservoir are poured into a glass jar. The glass jar is transferred to a humidity chamber (Associated Environmental Systems, Model LH-10) maintained at 60°C and 85% relative humidity. The uncapped glass jar is left in the humidity chamber for 7 days to slowly passivate the silicon nanoparticles by forming an oxide coating.

[0056] The silicon nanoparticle-coated LDDE pellets are isolated from the mineral oil by transferring the contents of the capture fluid reservoir to a syringe (COVIDIENT Luer lock sterile syringe, 60 cubic centimeters, Grainger catalog number 9VZF7) fitted with a filter (polytetrafluoroethylene syringe filter, 0.22 micrometer CELLTREAT brand filter). The syringe plunger is pushed down to drive the mineral oil out of the syringe through the filter while holding the silicon nanoparticle-coated LDDE pellets inside the syringe. Toluene is added to the syringe containing the silicon nanoparticle-coated LDDE pellets to rinse the pellets, and then the toluene is squeezed out of the syringe through the filter. Rinse again with toluene in the same manner. The resulting silicon nanoparticle-coated LDDE pellets are dried in an oven at 60°C. LPDE pellets coated with dried silicon nanoparticles exhibit visible photoluminescence when exposed to ultraviolet light (365 nanometer wavelength from Waveform Lighting's real UV LED flashlight with BLACKOUT® Filter Technology, catalog number 7023), indicating that the silicon nanoparticles are silicon quantum dots.

[0057] Sample 3: LDPE film with dispersed silicon quantum dots The process of Sample 1 is repeated using LDPE pellets coated with silicon nanoparticles prepared by a direct deposition procedure onto polymer host matrix material particles. The LDPE film emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots dispersed therein.

[0058] Samples using spray coating of silicon nanoparticles onto polymer host matrix material particles For these samples, a dispersion of silicon nanoparticles in a fluid is prepared, and then silicon nanoparticles are spray-coated onto particles of a polymer host matrix material to form silicon nanoparticle-coated particles. Subsequently, the silicon nanoparticle-coated particles are used to form a polymer material.

[0059] Preparation of silicon nanoparticle dispersion Inside the glove box, 12 g of mineral oil capturing fluid is placed in an open container ("capturing fluid reservoir") 6. The capturing fluid is a 5 wt percent solution of 1-octadecene in mineral oil. The capturing fluid reservoir is transferred to the load lock 2. The load lock 2 is evacuated using a roughing pump until the pressure is less than 2.67 Pa. The main collection chamber 4 is evacuated using a high vacuum pump 11 (a turbomolecular pump with a pumping speed of 600 liters / second (an Ebara S50 semiconductor pump with a pumping speed of 5,000 liters / minute) assisted by the roughing pump) to 6.67 × 10⁻⁶ -5 Evaporate until the pressure is less than Pa. Use the transfer arm 2c to transfer the captured fluid reservoir through the gate valve 3 into the main collection chamber 4 and place it on the captured fluid reservoir holder 7. Place the captured fluid reservoir 6.5 cm below the orifice 5b using the captured fluid reservoir holder 7. Close the gate valve 3 and open the main collection chamber 4 to 6.67 × 10⁻¹⁰ -5 The fluid is exhausted to a pressure of Pa. The fluid capture reservoir holder 7, and consequently the fluid capture reservoir, is rotated at a speed of 12 revolutions per minute.

[0060] A gas stream of 50 SCCM nanoparticle precursors and 7 SCCM H2 carrier gas is supplied to the inlet end 5a and exits through the dielectric discharge tube 5 to the main collection chamber 4 via the discharge tube orifice 5b. Plasma 9 is generated in the discharge tube 5 by applying an AC sinusoidal bias to electrodes 8a and 8b of the double copper electrode 8. The sinusoidal bias is generated using a Tektronix AFG3252 function generator and an Electronic and Innovation 3200L Class A radio frequency amplifier connected to the electrodes. The sinusoidal bias between the electrodes generates a capacitively coupled ultra-high frequency (90-500 megahertz) plasma in the dielectric discharge tube. The frequency source is adjusted to provide the maximum power coupled to the plasma while minimizing the sinusoidal drive amplitude. The coupled power density of the plasma is 130 watts / cm² (W / cm²). 2 It is larger than ). Silicon nanoparticles are formed in the plasma 9, exit the dielectric discharge tube through the discharge tube orifice 5b in the main collection chamber 4, and enter the capture fluid in the capture fluid reservoir.

[0061] The generation and collection of silicon nanoparticles is continued in this manner for 95 minutes, after which the power to electrodes 8a and 8b is switched off. The gate valve 3 is opened, and the capture fluid reservoir is returned to the load lock 2 using the transfer arm 2c. The capture fluid reservoir is transferred to the glove box, the contents of the capture fluid reservoir are poured into a glass jar, the glass jar is placed in an ultrasonic bath (Branson 2510, 40 kHz), and ultrasonic stirring is applied for 1 hour. The glass jar is then transferred to a humidity chamber (Associated Environmental Systems, Model LH-10) maintained at 60°C and 85% relative humidity. The uncapped glass jar is left in the humidity chamber for 7 days to slowly passivate the silicon nanoparticles by forming an oxide coating.

[0062] Transfer the capture fluid and silicon nanoparticle solution to a centrifuge tube and centrifuge using a Sorvall Biofuge Primo centrifuge. Using a pipette, remove the supernatant capture fluid from the centrifuge tube, leaving the silicon nanoparticles. Fill the centrifuge tube with toluene and gently stir by hand to rinse the silicon nanoparticles, then centrifuge the tube to separate the toluene from the silicon nanoparticles. Remove the toluene with a pipette. Repeat the toluene rinsing and centrifugation separation three times. Next, add toluene to the centrifuge tubes containing the silicon nanoparticles and sonicate them as described above to produce a clear dispersion of silicon nanoparticles in toluene. The dispersion exhibits visible photoluminescence when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating that the silicon nanoparticles are silicon quantum dots.

[0063] Sample 4: Silicon quantum dots are spray-coated onto LDPE, and then an LDPE film in which silicon quantum dots are dispersed is formed. Using an airbrush (Central Pneumatic, product 95810), a dispersion of silicon nanoparticles in toluene is sprayed onto LDPE pellets to form silicon nanoparticle-coated LDPE pellets. 10 ml of 1,000 parts by weight of silicon nanoparticles per 1 million parts by weight of toluene is sprayed onto the LDPE pellets. The silicon nanoparticle-coated LDPE pellets are dried in an oven at 60°C for 24 hours. The dried silicon nanoparticle-coated LDPE pellets exhibit visible photoluminescence upon exposure to ultraviolet light (365 nanometer wavelength from Waveform Lighting's real UV LED flashlight with BLACKOUT® Filter Technology, catalog no. 7023), indicating that the silicon nanoparticles are silicon quantum dots.

[0064] LDPE pellets coated with 3-4 grams of silicon nanoparticles are placed between two PTFE sheets, and the resulting PTFE sheets and silicon nanoparticle-coated LDPE pellets are placed in a vacuum bag (FoodSaver vacuum Seal Rolls, part number 191396). The vacuum bag is evacuated (using FoodSaver part number FSSMSL0160-000), and then, while still inside the vacuum bag, a clamshell heat press (Geo Knight & Co., model DK16) is used to compress the two PTFE sheets against the silicon nanoparticle-coated LDPE pellets at 150°C for 30 minutes at a pressure range of 4-6 on the clamshell heat press's pressure scale to create an LDPE film between the PTFE sheets. The LDPE film and PTFE sheets are removed from the vacuum bag. The LDPE film emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots dispersed within it.

[0065] Sample 5: A PVB sheet is spray-coated with silicon quantum dots, and then a PVB film in which silicon quantum dots are dispersed is formed. Cut the PVB sheet into two PVB sheets with dimensions of 7.62 cm x 2.54 cm. Using an airbrush (Central Pneumatic, product number 95810), spray a dispersion of silicon nanoparticles in toluene onto one side of each of the two PVB sheets to form silicon nanoparticle-coated PVB sheets. Spray 10 ml of 1,000 parts by weight of silicon nanoparticles per 1 million parts by weight of toluene onto the PVB sheets. Dry the silicon nanoparticle-coated PVB sheets at 25°C. Place the silicon nanoparticle-coated PVB sheets on top of each other so that the silicon nanoparticle-coated surfaces are in contact with each other, and place them between two PTFE sheets in a vacuum bag (FoodSaver vacuum Seal Rolls, product number 191396). The vacuum bag is emptied (using FoodSaver part number FSSMSL0160-000), and then, while still inside the vacuum bag, a clamshell heat press (Geo Knight & Co., model DK16) is used to compress two PTFE sheets against a PVB sheet coated with silicon nanoparticles at 150°C for 30 minutes at a pressure range of 4-6 on the clamshell heat press's pressure scale to produce a single PVB film between the PTFE sheets. The PVB film and PTFE sheets are removed from the vacuum bag. The PVB film emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots dispersed within it.

[0066] The resulting PVB film containing silicon nanoparticles is placed between two glass microscope slides and placed in a vacuum bag (FoodSaver vacuum seal rolls, part number 191396). The vacuum bag is evacuated (using FoodSaver part number FSSMSL0160-000), and then, while still inside the vacuum bag, a clamshell heat press (Geo Knight & Co., model DK16) is used to compress two PTFE sheets against the silicon nanoparticle-coated PVB sheet at 120°C for 10 minutes at a pressure range of 4-6 on the clamshell heat press's pressure scale, thereby producing a laminated glass sample of two glass pieces with the silicon nanoparticle-containing PVB laminated together between them. The laminated glass sample emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots.

[0067] Sample 6: Silicon quantum dots are spray-coated onto PLA, and then a PLA film in which silicon quantum dots are dispersed is formed. Cut two pieces of PLA ("PLA Sheets") from a PLA cold cup to provide pieces with dimensions of 7.62 cm × 2.54 cm. Using an airbrush (Central Pneumatic, Item No. 95810), spray a dispersion of silicon nanoparticles in toluene onto one side of each of the two PLA sheets to form silicon nanoparticle-coated PLA sheets. Spray 10 ml of 1,000 parts by weight of silicon nanoparticles per 1 million parts by weight of toluene onto the PLA sheets. Dry the silicon nanoparticle-coated PLA sheets at 25°C. Place the silicon nanoparticle-coated PLA sheets on top of each other so that the silicon nanoparticle-coated surfaces are in contact with each other, and place them between two PTFE sheets in a vacuum bag (FoodSaver vacuum Seal Rolls, Item No. 191396). The vacuum bag is emptied (using FoodSaver part number FSSMSL0160-000), and then, while still inside the vacuum bag, a clamshell heat press (Geo Knight & Co., model DK16) is used to compress two PTFE sheets against a PLA sheet coated with silicon nanoparticles at 180°C for 30 minutes at a pressure range of 4-6 on the clamshell heat press's pressure scale to create a single PLA film between the PTFE sheets. The PLA film and PTFE sheets are removed from the vacuum bag. The PLA film emits light when exposed to ultraviolet light (365 nanometer wavelength from a real UV LED flashlight with BLACKOUT® Filter Technology from Waveform Lighting, catalog number 7023), indicating the presence of silicon quantum dots dispersed within it.

[0068] A 1 cm x 1 cm piece was cut from a PLA film and dissolved in a 50% potassium hydroxide aqueous solution. The PLA rapidly decomposed into potassium lactate. The silicon quantum dots were etched into potassium silicate, as evidenced by the rapid loss of orange photoluminescence. This demonstrates that a sample of polymer film in which silicon quantum dots are dispersed can rapidly decompose at the end of its service life.

Claims

1. A method for preparing a polymer host matrix material in which silicon nanoparticles are dispersed, a. To provide a piece of polymer host matrix material coated with silicon nanoparticles, b. Softening a piece of polymer host matrix material coated with silicon nanoparticles to form a softened piece of polymer host matrix material, c. A method comprising blending softened pieces of the polymer host matrix material together with the silicon nanoparticles on the surface of the softened pieces of the polymer host matrix material to form a single mass of polymer host matrix material in which silicon nanoparticles are dispersed.

2. The method according to claim 1, wherein the silicon nanoparticles are silicon quantum dots.

3. The method according to claim 2, wherein the silicon nanoparticles are passivated silicon quantum dots.

4. The method according to claim 3, further comprising forming an oxide coating on silicon quantum dots after the silicon quantum dots have been fabricated, in order to form a passivation oxide coating on the silicon quantum dots.

5. The following method: a. A method for directly depositing silicon nanoparticles onto a piece of polymer host matrix material when silicon nanoparticles are produced. b. A method for depositing silicon nanoparticles in a capture fluid containing pieces of polymer host matrix material when silicon nanoparticles are produced, and The method according to any one of claims 1 to 4, further comprising providing a piece of polymer host matrix material coated with silicon nanoparticles by any one or any combination of the following methods: c. spray coating a piece of polymer host matrix material with a solvent dispersion of silicon nanoparticles.

6. The method according to claim 5, further comprising forming the silicon nanoparticles using a VHFLPP process.

7. The method according to claim 6, wherein the VHFLPP process comprises capturing the silicon nanoparticles in a capture fluid containing a functionalizing agent.

8. The method according to any one of claims 1 to 7, wherein the polymer host matrix material is a thermoplastic polymer composition.

9. The method according to any one of claims 1 to 8, wherein a single mass of a polymer host material in which the silicon nanoparticles are dispersed is further formed into a polymer film, and the silicon nanoparticles are quantum dots that absorb light of wavelengths less than 400 nanometers which are less suitable for agriculture, and emit light of wavelengths in the range of 600 to 750 nanometers which are more suitable for agriculture.

10. The method according to any one of claims 1 to 9, further comprising the steps of: if the material is not already in a fluid state, softening a single mass of polymer host matrix material in which the silicon nanoparticles are dispersed to form a fluid polymer composition; and then making the fluid polymer composition fluid without mixing or by making it fluid to create a difference in the concentration of silicon nanoparticles in the polymer host matrix material.

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