TW202210550A - Flexible polymer blend, electronic device and resistive memory device comprising the same, and manufacturing method of resistive memory device - Google Patents

Abstract

The present invention provides a flexible polymer blend, electronic device and resistive memory device comprising the same, and manufacturing method of resistive memory device. The polymer blend comprises a first material, comprising a poly(butylene succinate) or a derivative thereof; and a second material, comprising a conductive organic polymer; wherein the polymer blend is formed by blending the first material and the second material, and the polymer blend is biodegradable. The present invention can be applied to environmentally-friendly electronic products and exhibit excellent performance.

Description

Flexible polymer blends and electronic devices and resistive memory devices including the same and methods of making resistive memory devices

The present invention relates to a flexible polymer blend and an electronic device comprising the same, in particular the polymer blend is a biodegradable polymer elastomer and can be used as a flexible resistive memory integrated with a substrate and a charge trapping memory layer body device.

Compared with inorganic material-based electronic devices, polymer-based electronic devices have attracted extensive research interest due to their flexibility, low-cost potential, ease of processing, good scalability, and large data storage capacity. However, these synthetic polymers are mainly derived from fossil fuels, which can lead to serious environmental pollution and rapidly growing waste.

To solve this problem, various renewable or biodegradable polymers have been used in organic electronic devices as substrates, dielectric layers or active layers, such as deoxyribonucleic acid, polysaccharides, and bio-based aliphatic polyesters, etc. However, , even if these sustainable materials have sufficient physical properties, they still face serious challenges when they are practically used in devices.

In terms of basic electronic components of resistive memory cells using polymer materials, polymer composites containing charge trapping cells in an insulating matrix have been studied in the past for resistive memory devices, however, the insulation in these studies The substrate is neither renewable nor biodegradable, or is biodegradable but the substrate used exhibits poor flexibility. Furthermore, currently only sustainable materials have been applied to a single layer in a device, rather than integrated layers. There are currently no published flexible resistive memory devices integrated with biodegradable polymer elastomer substrates and charge trapping memory layers, which will be of considerable importance in the field of wearable electronics.

In view of this, the main object of the present invention is to provide a flexible polymer blend, the polymer blend includes: a first material, the first material includes polybutylene succinate polymer or derivatives thereof and a second material, the second material includes a conductive organic polymer; wherein, the polymer blend system is formed by blending the first material and the second material, and the polymer blend Biodegradable.

In a preferred embodiment, the conductive organic polymer is selected from the group consisting of polyacetylene-based polymers, poly-p-styrene-based polymers, polyaniline, polypyrrole-based polymers, polyfluorene-based polymers, poly p-phenylene sulfide (poly-p-phenylenesulphide), polybenzazole-based polymers, polycarbazole-based polymers, polyazulene-based polymers, polynaphthalene-based polymers, polythiophene-based polymers, poly The group consisting of thiophene vinylidene polymers and their derivatives.

In a preferred embodiment, the conductive organic polymer is a polyfluorene-based polymer or a derivative thereof.

In a preferred embodiment, the conductive organic polymer is present in an amount of 1 wt % to 30 wt % relative to the first material.

In a preferred embodiment, the conductive organic polymer is poly[(9,9-bis(3'- N,N -dimethylamino)propyl)-2,7-fluorene)-alt- 2,7-(9,9-dioctylfluorene)], and it is present in an amount of at least 1 wt% to 20 wt% relative to the first material.

Another object of the present invention is to provide an electronic device having the polymer blend as described above.

Another object of the present invention is to provide a resistive memory device, which sequentially includes: a bottom electrode layer, the polymer blend as described above as an active layer and a top electrode layer; wherein the active layer is located on the Between the bottom electrode layer and the top electrode layer, and the positions of the bottom electrode layer and the top electrode layer are specifically aligned, to form an array of intersections of memory cells with effective bonding surfaces.

In a preferred embodiment, the resistive memory device further includes a substrate, which is a biodegradable biobased polymer.

In a preferred embodiment, the bottom electrode layer and/or the top electrode layer include silver nanowires.

Another object of the present invention is to provide a method for manufacturing a resistive memory device, comprising the following steps: (a) preparing a substrate; (b) coating the substrate with a conductive substance to serve as a bottom electrode layer; (c) ) preparing a polymer blend solution as previously described, and applying the polymer blend onto the electrode by at least one technique selected from the group consisting of spin coating, spray coating, and solution shear coating, to as an active layer; and (d) coating the active layer with a conductive material to serve as a top electrode layer; wherein the bottom electrode layer and the top electrode layer are positioned specifically aligned to form a crossover of memory cells with effective junction surfaces point array.

As mentioned above, the polymer blend of the present invention is not only flexible, but also has good processability, heat and chemical resistance, biodegradability and mechanical properties, and the blended film formed by the polymer blend is non-toxic and can be disintegrate. By applying the novel polymer blend of the present invention to electronic devices, electronic products that are environmentally friendly and flexible can be prepared, especially suitable for use in flexible electrical storage devices as active layers, and can be widely used in wearables and implantable bioelectronic applications, with rich potential application prospects. It can be seen that the present invention has considerable advantages over the prior art. In addition, the fabrication method of the resistive memory device of the present invention can utilize different processing techniques such as spin coating, spray coating, and solution shearing to adjust the size of the phase separation region in the polymer blend.

The detailed description and technical content of the present invention are described below with reference to the drawings. Furthermore, the drawings in the present invention are not necessarily drawn according to the actual scale for the convenience of description. These drawings and their scales are not intended to limit the scope of the present invention, and are described here in advance.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The following terms used throughout this application shall have the following meanings.

"Or" means "and/or" unless stated otherwise. "Comprising" means not excluding the presence or addition of one or more other components, steps, operations or elements to the described component, step, operation or element, respectively. The terms "comprising," "including," "containing," "including," and "having" as used herein are interchangeable and not limiting. As used herein and in the appended claims, the singular forms "a" and "the" include plural referents unless the context otherwise dictates. For example, the terms "a," "the," "one or more," and "at least one" are used interchangeably herein.

The present invention relates to a flexible polymer blend comprising: a first material comprising polybutylene succinate polymer or derivatives thereof; and a second material , the second material includes a conductive organic polymer; wherein, the polymer blend system is formed by blending the first material and the second material, and the polymer blend has biodegradability. In another aspect, the present invention also relates to an electronic device having the polymer blend as described above. Furthermore, the present invention also relates to a resistive memory device, which sequentially includes: a bottom electrode layer, the polymer blend as described above as an active layer and a top electrode layer; wherein the active layer is located on the bottom electrode Layer and the top electrode layer, and the position of the bottom electrode layer and the top electrode layer are specifically aligned to form an array of intersections of memory cells with effective bonding surfaces.

The present invention also relates to a method for manufacturing a resistive memory device, comprising the following steps: (a) preparing a substrate; (b) coating the substrate with a conductive substance to serve as a bottom electrode layer; (c) preparing as before the polymer blend solution, and applying the polymer blend to the electrode by at least one technique selected from spin coating, spray coating, and solution shear coating to serve as an active layer and (d) coating the active layer with a conductive material to serve as a top electrode layer; wherein the bottom electrode layer and the top electrode layer are positioned specifically aligned to form an array of intersections of memory cells with effective bonding surfaces. Different processing techniques such as spin coating, spray coating, and solution shearing described above can be used to adjust the size of the phase separation zone in the polymer blend.

The term "poly(butylene succinate) (PBS)" as described herein is a semi-crystalline aliphatic polyester derived from renewable resources with a low glass transition temperature and a Good processability, heat and chemical resistance, biodegradability and mechanical properties.

The term "conductive organic polymer" as used herein refers to a high molecular polymer with electrical conductivity. In a preferred embodiment, the conductive organic polymer is selected from the group consisting of polyacetylene-based polymers, poly-p-styrene-based polymers, polyaniline, polypyrrole-based polymers, polyfluorene-based polymers, poly p-phenylene sulfide (poly-p-phenylenesulphide), polybenzazole-based polymers, polycarbazole-based polymers, polyazulene-based polymers, polynaphthalene-based polymers, polythiophene-based polymers, poly The group consisting of thiophene vinylidene polymers and their derivatives. In a preferred embodiment, the conductive organic polymer is a polyfluorene-based polymer or a derivative thereof. In a more preferred embodiment, the conductive organic polymer is poly[(9,9-bis(3'- N,N -dimethylamino)propyl)-2,7-fluorene)-alt- 2,7-(9,9-dioctylfluorene)] (herein referred to as PFN).

The conductive organic polymer described herein preferably has a proportion relative to the first material, for example, in an amount of 1 wt % to 30 wt %, including but not limited to: 1 wt % to 30 wt %, 3 wt% to 30 wt%, 5 wt% to 30 wt%, 7 wt% to 30 wt%, 10 wt% to 30 wt%, 13 wt% to 30 wt%, 15 wt% to 30 wt%, 17 wt% to 30 wt%, 20 wt% to 30 wt%, 23 wt% to 30 wt%, 25 wt% to 30 wt%, 27 wt% to 30 wt%, 1 wt% to 25 wt%, 3 wt% to 25 wt%, 5 wt% to 25 wt%, 7 wt% to 25 wt%, 10 wt% to 25 wt%, 13 wt% to 25 wt%, 15 wt% to 25 wt%, 17 wt% to 25 wt% , 20 wt% to 25 wt%, 23 wt% to 25 wt%, 1 wt% to 20 wt%, 3 wt% to 20 wt%, 5 wt% to 20 wt%, 7 wt% to 20 wt%, 10 wt% to 20 wt%, 13 wt% to 20 wt%, 15 wt% to 20 wt%, 17 wt% to 20 wt%, 1 wt% to 15 wt%, 3 wt% to 15 wt%, 5 wt% to 15 wt%, 7 wt% to 15 wt%, 10 wt% to 15 wt%, 13 wt% to 15 wt%, 1 wt% to 10 wt%, 3 wt% to 10 wt%, 5 wt% to 10 wt%, 7 wt% to 10 wt%, 1 wt% to 10 wt%, 1 wt% to 5 wt%, 3 wt% to 5 wt%. In a preferred embodiment, the conductive organic polymer is present in an amount of 1 wt % to 20 wt % relative to the first material. In a more preferred embodiment, the conductive organic polymer is poly[(9,9-bis(3'- N,N -dimethylamino)propyl)-2,7-fluorene)-alt- 2,7-(9,9-dioctylfluorene)], and it is present in an amount of at least 1 wt% to 20 wt% relative to the first material.

The polymer blend of the present invention not only has flexibility, but also has good processability, heat and chemical resistance, biodegradability and mechanical properties. It can be used in various electronic devices, especially, it can be used as the substrate of flexible devices or the active layer of memory devices. In particular, it can be applied to electrical storage (memory) devices, such as wearable and implantable memory or disposable memory IC cards. In a preferred embodiment, the present invention provides an electronic component, an electronic device, comprising the polymer blend as described above. In a preferred embodiment, the present invention provides an electronic device comprising the polymer blend as described above as an active layer and/or a substrate.

Electronic devices described herein, such as, but not limited to, electrical storage devices, and are not limited to forming rigid or flexible electrical storage devices, in particular a basic electronic component of resistive memory (memory) cells using the aforementioned polymer blends, The aforementioned polymer blend has a capacitor-like structure sandwiched between two metal electrodes. In device operation, the writing process occurs by applying a voltage bias or pulse to the device, resulting in switching between a high-resistance state and a low-resistance state. As the transition occurs, power down the power sources that determine the volatility of data storage (such as rewritable memory, flash-type, write-once-read-many (WORM)-type memory, static random access memory (SRAM), and dynamic random access memory After accessing memory (DRAM), the device will remain in one of two states. Manipulating the morphology of the charge-trapping cells can further tune the electrical storage properties. That is, in the electrical storage device, the polymer blend as the active layer is located between a bottom electrode layer and a top electrode layer, and the positions of the bottom electrode layer and the top electrode layer are specifically aligned to form an effective bonding surface. The cross-point array of the storage cells; the above-mentioned specific alignment form can be adjusted by those skilled in the art according to requirements. In a preferred embodiment, the positions of the bottom electrode layer and the top electrode layer of the electrical storage device are vertically aligned to form an array of intersections of memory cells with active junctions.

The aforementioned rigid or flexible electrical storage devices, for example, can be fabricated using rigid substrates and/or rigid electrodes in rigid electrical storage devices; flexible electrical storage devices can be fabricated using flexible substrates and flexible electrodes. The aforementioned rigid substrates and rigid electrodes, such as indium oxide, tin oxide, indium-tin composite oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide, It is made of conductive materials such as zinc oxide-gallium trioxide (ZnO-Ga ₂ O ₃ ) and zinc oxide-alumina (ZnO-Al ₂ O ₃ ). Metal wires or conductive materials are arranged on the aforementioned flexible substrates and flexible electrodes, such as high molecular polymers. In a preferred embodiment, the substrate for the electrical storage device is a biodegradable biobased polymer.

The "electrodes" described herein can be applied to the bottom electrode layer and/or the top electrode layer as required, and the electrode materials can be, for example, but not limited to: gold, silver, rubidium, palladium, nickel, molybdenum, aluminum, alloys thereof, or combinations thereof Wait. Rigid electrodes can be prepared directly using the aforementioned electrode materials. The flexible electrode is, for example, but not limited to, a conductive polymer, or the aforementioned electrode material is coated on a flexible polymer. In a preferred embodiment, the electrical storage device of the present invention comprises a layer of a bio-based polymer with silver nanowire (AgNW) electrodes.

"Conductive substances" as used herein include conductors and semiconductors, such as metals, the aforementioned conductive materials, or conductive polymers, and the like.

As shown in FIG. 2 , the resistive memory device 200 of the present invention is fabricated on the electrode 21 by using biodegradable PBS and a charge trapping layer (active layer 22 ) of a conductive organic polymer; wherein the resistive memory The electrical memory properties of the device will be governed by the composition and size of the charge-trapping conductive organic polymer, which can be characterized by transmission electron microscopy, spectrofluorimetry, and confocal laser images. In a preferred embodiment, the resistive memory device of the present invention is fabricated on electrodes using PBS and a charge trapping layer of semiconductor PFN. In a preferred embodiment, the resistive memory device of the present invention is fabricated on electrodes with silver nanowires using PBS and a charge trapping layer of a conductive organic polymer. In a preferred embodiment, the resistive memory device of the present invention is fabricated on electrodes and substrates using PBS and a charge trapping layer of a conductive organic polymer. In a preferred embodiment, the resistive memory device of the present invention is fabricated using PBS and a charge trapping layer of a conductive organic polymer on a biodegradable bio-based polymer with electrodes. In a preferred embodiment, the resistive memory device of the present invention is fabricated using a charge trapping layer of PBS and semiconducting PFN on a biodegradable bio-based polymer with silver nanowire electrodes. In a preferred embodiment, the resistive memory device of the present invention is fabricated using a charge trapping layer of PBS and semiconductor PFN on a biodegradable Ecoflex elastomer substrate with silver nanowire electrodes.

In a preferred embodiment, the rigid resistive memory device of the present invention has a sandwich structure of a rigid substrate containing conductive material/the aforementioned polymer blend film/the aforementioned electrode material. In a preferred embodiment, the rigid resistive memory device of the present invention comprises: a glass substrate with ITO/the aforementioned polymer blend film/the aforementioned electrode material sandwich structure. In a preferred embodiment, the rigid resistive memory device of the present invention comprises: a glass substrate with ITO/(PFN/PBS) polymer blend film/aluminum (Al) sandwich structure.

In a preferred embodiment, the flexible resistive memory device of the present invention has a sandwich structure of a flexible polymer substrate/electrode material or conductive material/the aforementioned polymer blend film/electrode material or conductive material. In a preferred embodiment, the flexible resistive memory device of the present invention has a sandwich structure of conductive organic polymer/the aforementioned polymer blend film/electrode material or conductive material. In a preferred embodiment, the flexible and biodegradable resistive memory device of the present invention has: a bio-based polymer substrate/electrode material or conductive material/interlayer of the aforementioned polymer blend film/electrode material or conductive material structure. In a preferred embodiment, the flexible and biodegradable resistive memory device of the present invention has: a bio-based polymer substrate/electrode material or conductive material/(PFN/PBS) polymer blend film/electrode material or Sandwich structure of conductive materials. In a preferred embodiment, the flexible and biodegradable resistive memory device of the present invention comprises: bio-based polymer substrate/silver nanowires/(PFN/PBS) polymer blend film/silver nanowires The sandwich structure. In a preferred embodiment, the flexible resistive memory device of the present invention has a sandwich structure of Ecoflex substrate/silver nanowires/the aforementioned polymer blend film/silver nanowires. In a preferred embodiment, the flexible resistive memory device of the present invention has a sandwich structure of Ecoflex substrate/silver nanowires/(PFN/PBS) polymer blend film/silver nanowires.

The following non-limiting examples of aspects of the invention are provided primarily to illustrate the aspects of the invention and the benefits achieved. [Example]

In the polymer blends of the following examples, PBS is used as the first material, and polyfluorene-based polymer (PFN), a conductive organic polymer, is selected as the second material, and the first material is blended with the second material Instead, a PFN/PBS polymer blend is formed. PFN/PBS blend films were then prepared using different coating methods, and the films were used to fabricate rigid and flexible environmentally friendly resistive memory devices. A. Materials for the experimental part :

Poly(1,4-butylene succinate) extended with cyclohexane diisocyanate (1,6-diisocyanatohexane, PBS) was purchased from Sigma-Aldrich (USA), and used as polymer matrix . Poly[(9,9-bis(3'- N , N -dimethylamino)propyl)-2,7-fluorene) -alt -2,7-(9,9-dioctylfluorene)] (PFN) was obtained from Machine Light Technology Co., Ltd. (Taiwan) and was used as a charge trapping material. Dopamine hydrochloride (Sigma-Aldrich), 2-amine-2-hydroxymethyl-1,3-propanediol (Tris Base, Sigma-Aldrich), anhydrous chloroform (CF, Sigma-Aldrich) and methanol (MeOH, Sigma-Aldrich) Use as is. Silver nanowire (silver nanowire, AgNW, AW060, length 10-20 μm, diameter 55-75 nm) and biodegradable Ecoflex elastomer were purchased from Kechuang Co., Ltd. (China) and BASF Co., Ltd. (Germany). Preparation of PFN/PBS Blend Membranes Using Different Coating Methods

The composition of film samples prepared by different methods is controlled in the range of 0.1-0.15. PFN/PBS blends (i.e. PFN/PBS-5, PFN/PBS-10 and PFN/PBS-15) at a concentration of 10 mg mL ^-1 (9:1, v/v) in CF/MeOH co-solvent, It was stirred at 50°C for 3 hours, and then filtered through a PTFE membrane syringe filter (pore size 0.22 μm). Note that the values after PFN/PBS are expressed as the composition (weight percent, wt%) of PFN in the PBS matrix. The prepared solutions are then applied by three techniques to substrates such as quartz plates, copper masks, and indium tin oxide (ITO) glass, which are already conductive or contain conductive materials so that both As the bottom electrode layer, the aforementioned techniques include (1) spin coating, (2) spray coating, and (3) solution shearing in an atmospheric environment. The experimental parameters and details of the corresponding thin film samples produced by the aforementioned various methods are described as follows: (1) PFN/PBS-5 spin-coated film (Fig. 1a): Using the spin-coating experimental device 100A, the polymerization was carried out at a speed of 1000 rpm. (2) PFN/PBS-5 spray film (FIG. 1b): Using spray experimental setup 100B, the coating (polymer blend solution 12) was transferred to the substrate 11 by spin coating Hand-held spray gun, and then sprayed on the substrate 11 heated at 50°C for 10 seconds with a distance of 10 cm from the nozzle to the substrate 11; (3) PFN/PBS-5 solution shearing film (Fig. 1c): using the solution Shearing experimental device 100C, both the substrate 11 and the shearing plate 13 are placed horizontally by vacuum (ie, the shearing angle is kept at 0 degrees), and the substrate 11 is set on an unheated workbench with a microcontroller The shearing plate 13 was lowered, the distance between the substrate 11 and the shearing plate 13 was set to 10 μm, and after about 20 μL of the prepared polymer blend solution 12 was placed on the substrate 11 with a pipette, The shear plate 13 was translated with a stepper motor at different rates (0.08, 0.10 and 0.50 mm s ⁻¹ ) to produce solution shear films. All film samples prepared by different treatments were placed on a hot plate at 50°C for 1 min to remove residual solvent before further analysis. Resistive memory device based on PFN/PBS blend film

A resistive memory device was fabricated on a glass substrate using a sandwich structure formed of ITO/(PFN/PBS blended film)/aluminum (Al). The patterned ITO glass was pre-cleaned sequentially with distilled water, isopropanol, and acetone for 15 minutes each using a sonicator. A PFN/PBS solution (9/1 (v/v)) at a concentration of 10 mg mL ^-1 in CF/MeOH co-solvent was coated on ITO patterned substrates as the active layer through different treatment procedures. The procedure is carried out with the above-mentioned optimization parameters. Finally, 100 nm Al as the top electrode was plated at a pressure of 10 ^-6 Torr and a rate of 0.8 Å s ^-1 using a thermal vapor deposition machine. The top electrodes were vertically aligned with the bottom ITO patterns by shadow masks to form intersection arrays with memory cells with active/active joint areas of 0.2×0.2, 0.4×0.4 and 0.6×0.6 mm ² . Note that thin films for resistive memory devices are also fabricated in atmospheric environments. Fabrication of flexible resistive memory devices on polymer substrates

Reagents A and B were mixed in a 1:1 mass ratio and cured at 80 ^° C for 1 hour to produce a commercial biodegradable Ecoflex elastomeric substrate, which is a biobased polymer. Meanwhile, 892 mg of Tris Base was dissolved in 360 g of distilled water, and the pH was kept around 9. After that, 516 mg of dopamine hydrochloride was added and dissolved. The heat cured Ecoflex elastomer was then dipped into the prepared solution and left at ambient temperature overnight. The PDA (polydopamine, polydopamine) modified Ecoflex was washed with methanol and dried at 50 ^° C for 1 hour.

First, the as-prepared biocompatible PDA-modified Ecoflex substrate was sprayed with conductive silver nanowire printing ink (2 mg mL ^-1 ) at 50 ^o C for 60 s as the bottom electrode. Then 20 µL of PFN/PBS-5 solution (10 mg mL ^-1 ) was sheared onto the electrode, with the working distance and velocity set to 10 µm and 0.30 mm/s, respectively. Finally, with the same process parameters again, the conductive silver nanowires are sprayed with ink to prepare the top electrode. Note that the electrodes were aligned by a shadow mask, while the active bonding area of the intersection array was fixed at 0.6 x 0.6 ^mm2 . Afterwards, an eco-friendly and disintegrable resistive memory device based on PFN/PBS-5 solution shear film was obtained. characteristic

The morphology of the PFN/PBS blend films was observed using a transmission electron microscope (TEM, FEI Tecnai G2 T20) and a two-photon laser conjugate focus microscope (Leica TCS SP5). In addition, the UV-Vis absorption and photoluminescence (PL) emission spectra of the polymer blend films were recorded on a Hitachi U-4100 UV-Vis spectrometer and a Horiba Jobin Yvon Fluorolog-3 spectrofluorometer, respectively. The photoluminescence quantum yield (PLQY) of the samples was calculated at an excitation wavelength of 360 nm by combining a spectrofluorometer with an integration sphere. The as-prepared resistive memory based on PFN/PBS blends was measured using a Keithley 4200-SCS Semiconductor Parameter Analyzer (Keithley Instruments, USA) in a glove box filled with N with a sweep voltage of -5 V to ₅ V Current-voltage characteristics and device performance of bulk devices. Film thickness and roughness for memory devices were measured by alpha step profilometer and atomic force microscope (AFM, Digital Instruments; spring constant: 15 N m ^-1 , resonance frequency: 330 kHz) . B. Results Morphology of Films Produced by Different Processing Techniques

The physical interaction between the tertiary amine on the PFN side chain and the isocyanate moiety of the extender in the PBS polymer is used to avoid aggregation of the conjugated polyelectrolyte PFN. Transmission electron microscopy (TEM), laser conjugate focus microscopy, and spectrofluorometry were used to investigate the properties of the films produced by the above-described processing methods in the phase-separated domain. As shown in Figure 3, the absorbance of the thin film samples was controlled in the range of 0.1-0.15, thus obtaining similar film thicknesses of 60-90 nm.

Figure 4 (left) shows TEM images of PFN/PBS-5 films prepared by different processing techniques, which show that the size of the phase separation domains of PFN in the PBS matrix is different. Although physical effects prevented the formation of massive PFN aggregates, PFN clusters with an average size up to 115.4 ± 30 nm were still observed in the PFN/PBS-5 spin-coated membrane (Fig. 4a). The average PFN domain size of the sprayed films was further reduced to 70.8 ± 16 nm due to the presence of aerosol droplets (Fig. 4b). Most notably, the meniscus-guided coating significantly reduced the phase-separated domains of the PFN/PBS-5 solution shear film to 10.1 ± 3 nm, conferring molecular alignment during processing (Fig. 4c). Therefore, the average PFN domain size in descending order is spin-coated film, sprayed film and solution sheared film.

In addition, under the same laser gain value, the laser conjugate focus image of the PFN/PBS-5 film is shown in Fig. 4 (right), and the inset shows its corresponding transmitted light image. In Figure 4a, the PFN/PBS-5 spin-coated film has uniform blue luminescence but shows relatively low brightness. The significant quenching of its luminescence intensity is due to the formation of larger PFN clusters. In contrast, the PFN/PBS-5 sprayed films with higher brightness still showed non-uniform luminescence despite the reduced PFN domain size (Fig. 4b). Compared with spin coating and spray coating, the solution shearing method can easily adjust the crystallinity, dispersion and phase separation of PFN/PBS blends by shear rate. As shown in Fig. 5, the grain size of PBS crystals increases with increasing shear rate, and PFN is well confined within its crystalline structure. However, when the shear rate is too fast, the uniformity of the luminescence becomes non-uniform. By optimizing the shear rate, a PFN/PBS-5 solution sheared film with only small PFN aggregates and uniform dispersion was obtained (Fig. 4c). The above observations indicate that the phase-separated morphology of PFN/PBS blend films can be controlled by various coating processes.

Spectrofluorimetry also confirmed the degree of phase separation despite microscopic analysis. Photoluminescence (PL) spectra of PFN and PFN/PBS-5 blend films are shown in Figures 6 and 7. In addition, Table 1 lists the corresponding photophysical properties. Since PBS is a non-emissive material, the optical properties of the PFN/PBS blends are entirely attributed to the conjugated polymer PFN. Compared with PFN, all PL spectra of PFN/PBS-5 blends excited at 360 nm show three distinct emission bands with peak emission wavelengths (λ ^PL _max ) divided into 0-0, 0-1 and 0 -2 intrachain singlet transition. The disappearance of the green emission band (λ ^PL _max at 524 nm) is caused by the strong π-π interactions of the rigid PFN-conjugated backbone and the weak dipole-dipole interactions of its side-chain functional groups, indicating that Physical interactions between PFN and PBS slowed the formation of severe aggregates and resulted in uniform dispersion. A subtle blue shift in the PL spectrum was observed as the phase-separated domain size was reduced, leading to increased photoluminescence quantum yield (PLQY). Therefore, the obtained PLQYs are spin-coated film (7.4%), sprayed film (12.4%) and solution sheared film (16.0%) in increasing order. Microscopic and optical analysis revealed that the phase-separated morphology of the polymer blends was affected by the processing technique, which may affect the charge trapping effect, discussed in detail below.

Table 1. Optical properties of PFN/PBS blend films. sample λ ^abs _max (nm) λ ^PL _max ^a (nm) I _0-1 / I _0-0 PLQY (%) PFN spin coating film 397 430, 454, 481, 524 - 5.9 PFN/PBS-5 394 427, 450, 479 0.606 7.4 PFN/PBS-5 spray film 390 426, 451, 479 0.619 12.4 PFN/PBS-5 Solution shear film 391 426, 450, 476 0.687 16.0 ^a Photoluminescence emission spectrum exhibited at an excitation wavelength of 360 nm.

Figure 8 shows the polarized PL emission spectra of PFN/PBS-5 spin-coated films and solution sheared films in parallel and perpendicular directions of shear force. The ratio of I _0–1 /I _0–0 was higher for nascent solution-sheared films compared to spin-coated films (Table 1), where the 0-0 to 0-1 transitions of polyfluorene were attributed to intrachain and interchain Intermolecular convergence. Increasing values of I _0–1 /I _0–0 indicate that the conjugated PFN domains have a tendency to form higher interchain ordering along the applied shear force. Therefore, a green emission band is also observed in the vertical direction due to the dense molecular packing caused by the meniscus-guided coating method. The biaxial molecular orientation of solution sheared films has a strong potential to enhance the flexibility of the films. Characteristics of Resistive Memory Devices

Figure 9 shows the current-voltage characteristics of a memory device ITO/(PFN/PBS blend)/Al on a glass substrate with a sweeping step of 0.1 V. The characteristics of all memory devices are summarized in Table 2, including switching performance, threshold voltage (V _th ), off current and on/off current ratio (I _{on / off} ). The following characterizes and analyzes the effect of PFN composition and phase separation domain size on resistive memory devices.

Table 2. Electrical characteristics of PFN/PBS based resistive memory devices. sample Switching performance _Vth (V) I _off (A) I _on/off PFN/PBS-5 spin coating film DRAM 2.8 1.0× ^10-5 10 ² PFN/PBS-10 WORM 1.6 2.0× ^10-7 10 ² PFN/PBS-5 spray film WORM 1.6 6.0× ^10-5 10 ² PFN/PBS-5 Solution shear film WORM 1.8 1.8× ^10-9 10 ⁴ PFN/PBS-5 Solution shear film (on Ecoflex substrate) WORM 2.6 1.9× ^10-14 10 ¹⁰

The electrical properties of the pristine PFN (Fig. 9a) are that it is conductive without any memory properties, and due to its semiconducting nature, the current rapidly increases to ^10-4 in the presence of an externally applied voltage. Incorporating the insulating PBS resin, the PFN can be encapsulated in the PBS matrix, resulting in a distinct bistable resistance state when a positive bias is applied. By varying the composition of the charge-trapping element PFN in the PBS matrix (approximately 5 wt% and 10 wt%), using spin coating, various resistance-switching properties were observed. As shown in Figure 9b, the current of the device with a small amount of PFN (5 wt %) initially exhibited typical volatile dynamic random access memory (DRAM) type switching performance. Initially, as the voltage is gradually swept from 0 V to 2.8 V, the fabricated device is in a high resistance state (HRS; off state; "0" signal in data storage). When the voltage is further increased, a sudden current jump occurs at the critical voltage of 2.8 V, which indicates a violent electronic transition to the low resistance state (LRS; ON state; "1" signal in data storage) . Note that the electronic transitions in the first scan act as a "write" procedure. However, when the power is turned off, the current returns to the HRS immediately. After that, it can be reprogrammed from HRS to LRS using a smaller threshold voltage (2.4 V). The device maintains a high I _on/off of 10 ² at 0.5 V. In contrast, the current of the device with high PFN content (10 wt%) (Fig. 9c) remained unchanged in the LRS for subsequent changes from 5 V to 0 V (scan 2) and from 0 to −5 V (Scan 3) of the scan. Even with the power turned off, the device was unable to perform the write procedure, representing non-volatile WORM-type memory performance with I _on/off as high as 10 ² at 0.5 V. Under a fixed voltage value bias, the device was stable in switching time for as long as 10 ⁴ seconds (Fig. 10a).

In addition to changing the PFN composition, the IV measurements shown in Figure 9 also illustrate the electrical properties and switching of devices based on PFN/PBS blends with the same charge-trapping elemental composition (i.e., PFN/PBS-5) but with different phase-separated domain sizes performance. To systematically analyze the effect of phase-separation morphology on device performance, the thickness of the as-prepared film was adjusted to be 60–90 nm, and the film had a smooth surface with an rms value of about 15.1–18.6 nm. In the case of the device using the PFN/PBS-5 sprayed film (Fig. 9d), it exhibits non-volatile WORM memory performance with I _on/off as high as 10 ² at 0.5 V and long-term stability of 10 ⁴ s sex (Figure 10b). Similarly, similar bistable transitions were observed in the device based on the sheared films of the PFN/PBS-5 solution (Fig. 9e), exhibiting non-volatile WORM memory performance. When a positive bias voltage is applied, the current of the device suddenly increases to LRS at a threshold voltage of 1.8 V. After that, its current remained at LRS with I _on/off up to 10 ⁴ at 0.5 V and subsequent scans (scans 2, 3 and 4) lasted 10 ⁴ s (Fig. 10c). This may be due to the densely packed structure due to the extension of polymer chains upon application of shear force. These results illustrate that tuning the size of the phase-separated domains can also control the resistive switching properties.

The memory performance of PFN/PBS-5 spin-coated film, sprayed film, and solution-sheared film exhibited DRAM, WORM, and WORM characteristics, respectively. FIG. 11 schematically illustrates the operation mechanism of ITO/(PFN/PBS-5 thin film)/Al based on the space charge limited current (SCLC) theory. In this device 300, insulative PBS polymer 31 acts as carrier blocking moieties, while PFN 32, a conjugated polyelectrolyte with low cytotoxicity and electrochemical properties, acts as an intercalating polymer matrix The charge trapping point in 31; when a voltage is applied, if sufficient energy is available, electrons 33 will be injected into the polymer blend film, trapped by functional side groups, and then trapped by the isolated PFN islands through a transition process (trapping islands) 32 escaped. For DRAM devices, charge may be trapped by PFN clusters; however, larger PFN domain separation prevents charge carrier transitions. As the loading ratio of PFN increases or the degree of phase separation decreases, the distance between individual PFN particles can be significantly shortened. Therefore, each PFN particle can easily overcome the transmittance threshold of the capture point, and then lower the energy barrier for charge transport, resulting in WORM-type memory performance. Therefore, the device using the PFN/PBS-5 solution sheared membrane with the smallest phase-separated domain size is expected to be an environmentally friendly resistive memory device with excellent performance. Environmentally friendly flexible resistive memory device

As shown in Figure 2, on the biodegradable and biocompatible PDA modified Ecoflex elastomer substrate 24, AgNW bottom electrode layer 21/(PFN/PBS-5 solution shear film) active layer 22/AgNW top electrode was used The sandwich structure of layer 23 produces an environmentally friendly resistive memory 200 . The devices shown in Figures 12 and 13 still exhibit non-volatile WORM-type memory performance with an excellent retention time of 7000 seconds. In addition, the _Ion/off of the prepared device is greatly improved to 10 ¹⁰ compared to the device using ITO and Al electrodes. The apparent reduction in off current is attributed to the smooth surface of the elastomeric substrate. Furthermore, as shown in Figure 14, the device was subjected to an additional 100 cycles of loosening the flexure protrusions to test its flexibility, and the Ion _/off of the device remained as high as ¹⁰⁹ despite a slight increase in the switching voltage to 5.8 V. This result indicates good electronic stability after bending. Therefore, the present invention successfully realizes an environmentally friendly flexible resistive memory device with stable and excellent device performance using biodegradable insulators and substrates. C. Conclusion

This example has demonstrated rigid resistive memory and eco-friendly flexible resistive memory using AgNW/(PFN/PBS-5 solution shear film)/AgNW sandwich structure on bio-based polymer substrates. Notably, the eco-friendly flexible resistive memory device has special non-volatile WORM-type memory characteristics, including high on/off current ratio (10 ¹⁰ ), low operating voltage (2.6 V), and excellent stability ( 7000 seconds save time). Furthermore, the device maintained a high on/off current ratio of ¹⁰⁹ after 100 cycles of bending tests. The apparent reduction in the phase-separated domain size in the PFN/PBS blend films using the meniscus-guided solution shearing technique results in a significant improvement in device performance. The prepared environment-friendly flexible resistive memory device is expected to be used in environment-friendly electronic products.

In conclusion, the polymer blend of the present invention is not only flexible, but also has good processability, heat and chemical resistance, biodegradability and mechanical properties, and the film formed by the polymer blend is nontoxic and disintegrating untie. By applying the novel polymer blend of the present invention to electronic devices, electronic products that are environmentally friendly and flexible can be prepared, especially suitable for use in flexible electrical storage devices as active layers, and can be widely used in wearables and implantable bioelectronic applications, with rich potential application prospects. In addition, the fabrication method of the resistive memory device of the present invention can utilize different processing techniques such as spin coating, spray coating, and solution shearing to adjust the size of the phase separation region in the polymer blend.

The present invention is explained above in more detail by means of preferred exemplary embodiments. Although exemplary embodiments have been disclosed herein, it should be understood that other variations are possible. Such variations are not to be considered as a departure from the spirit and scope of the exemplary embodiments of the present application, and all modifications obvious to those skilled in the art are still included within the scope of the appended claims.

100A: Spin coating experimental device 100B: Spraying experimental device 100C: Solution shear experimental device 11: Substrate 12: Polymer Blend Solution 13: Knife (Shearing Board) 200: Resistive memory device 21: Bottom electrode layer 22: Active layer 23: Top electrode layer 24: Substrate 300: WORM type resistive memory device 31: PBS matrix 32: PFN clusters 33: Electronics

Implementations of the present techniques will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic diagram of an experimental setup according to a preferred embodiment of the present invention: (a) spin coating method, (b) spray coating method and (c) solution shear coating method.

Figure 2 shows a schematic structure of a completely eco-friendly and disintegrable resistive memory device using PFN/PBS-5 solution shear film, (b) PBS and PFN structures according to preferred embodiments of the present invention .

Figure 3 shows the UV absorption spectra of PFN/PBS-5 films prepared by different processing methods according to preferred embodiments of the present invention: (a) spin-coated film, (b) sprayed film and (c) solution sheared membrane.

Figure 4 shows TEM images (left) and laser conjugate focus images (right) of PFN/PBS-5 according to the preferred embodiment of the present invention: (a) spin-coated film, (b) sprayed film and (c) ) solution sheared the membrane. The inset shows the corresponding transmitted light image.

Figure 5 shows the laser conjugate focus images of PFN/PBS-5 solution sheared films prepared from different shear rates according to a preferred embodiment of the present invention: (a) 0.08, (b) 0.10 and (c) 0.50 mm s ^-1 .

6 shows the PL emission spectra of PFN/PBS-5 films prepared by different treatment methods according to the preferred embodiment of the present invention.

FIG. 7 shows the PL emission spectrum of the PFN spin-coated film according to the preferred embodiment of the present invention.

Figure 8 shows polarized PL emission spectra of PFN/PBS-5 according to a preferred embodiment of the present invention: (a) spin-coated film and (b) solution sheared film.

Figure 9 shows the preferred embodiments according to the present invention based on (a) PFN spin-coated film, (b) PFN/PBS-5 spin-coated film, (c) PFN/PBS-10 spin-coated film, (d) ) I-V characteristics of resistive memory devices of PFN/PBS-5 sprayed film and (e) PFN/PBS-5 solution sheared film; the numbers in the legend in the figure are scan numbers.

Figure 10 shows (a) PFN/PBS-10 spin-coated film, (b) PFN/PBS-5 sprayed film, and (c) PFN/PBS- 5. Retention properties of resistive memory devices of solution shear films.

FIG. 11 shows a schematic diagram of the mechanism of a WORM type resistive memory device according to a preferred embodiment of the present invention.

Figure 12 shows the I-V characteristics of environmentally friendly resistive memory devices on PDA-modified Ecoflex elastomers using PFN/PBS-5 solution shear films according to a preferred embodiment of the present invention.

Figure 13 shows the retention characteristics of resistive memory devices using PFN/PBS-5 solution shear films on biodegradable Ecoflex substrates according to a preferred embodiment of the present invention.

14 shows the I-V characteristics of the eco-friendly resistive memory device according to the preferred embodiment of the present invention after 100 cycles of bending tests.

without.

200: Resistive memory device

21: Bottom electrode layer

22: Active layer

23: Top electrode layer

24: Substrate

Claims (10)

A flexible polymer blend comprising: a first material comprising a polybutylene succinate polymer or a derivative thereof; and a second material, the second material includes a conductive organic polymer; Wherein, the polymer blend system is formed by blending the first material and the second material, and the polymer blend has biodegradability. The polymer blend of claim 1, wherein the conductive organic polymer is selected from the group consisting of polyacetylene-based polymers, poly-p-styrene-based polymers, polyaniline, polypyrrole-based polymers, polyfluorene )-based polymers, poly-p-phenylenesulphide, polybenzazole-based polymers, polycarbazole-based polymers, polyazulene-based polymers, polynaphthalene-based polymers, poly The group consisting of thiophene-based polymers, polythiophene vinylidene polymers and their derivatives. The polymer blend of claim 1, wherein the conductive organic polymer is a polyfluorene-based polymer or a derivative thereof. The polymer blend of claim 1, wherein the conductive organic polymer is present in an amount of 1 wt% to 30 wt% relative to the first material. The polymer blend of claim 1, wherein the conductive organic polymer is poly[(9,9-bis(3'- N,N -dimethylamino)propyl)-2,7 -fluorene)-alt-2,7-(9,9-dioctylfluorene)], and it is present in an amount of at least 1 wt% to 20 wt% relative to the first material. An electronic device having the polymer blend of any one of claims 1 to 5. A resistive memory device, comprising sequentially: a bottom electrode layer, the polymer blend as claimed in any one of claims 1 to 5 as an active layer and a top electrode layer; wherein the active layer is located on the bottom The positions of the electrode layer and the top electrode layer, and the position of the bottom electrode layer and the top electrode layer, are specifically aligned to form an array of intersections of memory cells with effective bonding surfaces. The resistive memory device of claim 7, further comprising a substrate, the substrate being a biodegradable biobased polymer. The resistive memory device of claim 7, wherein the bottom electrode layer and/or the top electrode layer comprise silver nanowires. A manufacturing method of a resistive memory device, comprising the following steps: (a) preparing a substrate; (b) coating the substrate with a conductive substance as a bottom electrode layer; (c) preparing a polymer blend solution as claimed in any one of claims 1 to 5, and applying the polymer blend by at least one selected from the group consisting of spin coating, spray coating and solution shear coating technology is applied to the electrode as an active layer; and (d) covering the active layer with a conductive material as a top electrode layer; Wherein, the bottom electrode layer and the top electrode layer are specifically aligned to form a cross point array of memory cells with effective bonding surfaces.

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