Polymer with dual oxidation-reduction characteristic, resistive random access memory device and preparation of resistive random access memory device

Abstract

The invention relates to the technical field of information storage devices, in particular to a polymer with dual oxidation-reduction characteristics, a resistive random access memory device and preparation of the resistive random access memory device. Oxidation of the triphenylamine unit in the polymer with dual redox characteristics can reduce the energy band gap of the polymer, so that the transition of charge carriers is relatively easy, thereby promoting the redox process of the terpyridyl-iron coordination unit; the polymer resistive random access memory device with the dual oxidation-reduction characteristic has stable nonvolatile erasable storage performance, changes of opening and closing voltages are small in the continuous testing process, and application in the fields of information storage, logical operation and the like can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of information storage devices, and in particular to a polymer with dual redox properties, a resistive memory device and preparation thereof. Background Art

[0002] The rapid development and increasing popularity of computers are profoundly influencing and changing people's lifestyles and ways of thinking. Together with Internet communication technology, it has not only established a global high-speed communication network and social circle, but also promoted the development of modern information technologies such as the Internet of Things, big data, and artificial intelligence. At present, as major countries in the world have successively laid out intelligent manufacturing and smart city construction, various modern information technologies have been widely used, which has led to an explosive growth in the amount of global data. However, the miniaturization process of traditional silicon-based memory is gradually approaching its physical limit, and the performance improvement brought about by it is difficult to meet the growing needs of information storage and computing.

[0003] Unlike silicon-based storage technology, as a new type of storage technology proposed based on the electro-resistive effect, resistive memory does not require space to store charge and can better adapt to the needs of device miniaturization. In addition, resistive memory can not only rely on its own resistance changes to store information, but also build large-scale arrays to achieve parallel computing similar to the human brain, thereby realizing storage and computing integration functions. Therefore, resistive memory can effectively overcome the current limits of Moore's Law and von Neumann bottleneck problems, and will provide a path for the sustainable development of modern information storage and processing technology. Summary of the invention

[0004] In order to solve the above problems, an object of the present invention is to provide a polymer having dual redox properties, a resistive memory device and preparation thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] In the present invention, the structural formula of poly(BTA-Fe) is as shown below:

[0007]

[0008] Where n is 10 2 -10 4 A positive integer.

[0009] The first object of the present invention is to provide a method for preparing a polymer having dual redox properties, wherein the polymer is poly(BTA-Fe), and the preparation method comprises the following steps:

[0010] (A1) Synthesis of M1: Sodium hydroxide, ethanol and 2-acetylpyridine were mixed, and then 4-formylphenylboronic acid and ammonia water were added. After the primary reaction, the mixture was heated for a secondary reaction, and post-treatment was performed to obtain a white solid M1.

[0011] (A2) Synthesis of BTA: M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2 O, tert-butyl alcohol and M1 obtained in step (A1) are mixed and reacted, and post-treated to obtain green solid BTA;

[0012] (A3) Synthesis of poly(BTA-Fe): FeCl 2 ·4H 2 O, ethylene glycol and the BTA prepared in step (A2) are mixed and reacted, and then post-treated to obtain a dark brown solid poly(BTA-Fe);

[0013] Wherein, the chemical structural formula of M1 is shown in formula (I), and the chemical structural formula of M2 is shown in formula (II);

[0014]

[0015] Step (A2) and step (A3) are carried out in an inert atmosphere.

[0016] In one embodiment of the present invention, in step (A1), the usage ratio of sodium hydroxide, ethanol, 2-acetylpyridine, 4-formylphenylboronic acid and aqueous ammonia is 22.5 g: 300 mL: 18 mL-25 mL: 10-12 g: 150 mL;

[0017] Preferably, the usage ratio of sodium hydroxide, ethanol, 2-acetylpyridine, 4-formylphenylboronic acid and ammonia water is 22.5 g: 300 mL: 21 mL: 11.2 g: 150 mL.

[0018] In one embodiment of the present invention, in step (A1), during the first reaction, the temperature is 35 to 45° C. and the time is 5 to 7 h;

[0019] During the secondary reaction, the temperature is 80-100°C and the time is 22-26h;

[0020] Preferably, in step (A1), during one reaction, the temperature is 40° C. and the time is 6 h;

[0021] During the secondary reaction, the temperature was 90°C and the time was 24h.

[0022] In one embodiment of the present invention, in step (A2), M2, Pd(PPh 3) 2 Cl 2 , sodium carbonate, toluene, H 2 O, the dosage ratio of tert-butyl alcohol to M1 is 3-4mmol: 0.30mmol: 24mmol: 80mL: 30mL: 10mL: 7-9mmol;

[0023] Preferably, M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2 The ratio of O, tert-butyl alcohol and M1 is 3.5mmol:0.30mmol:24mmol:80mL:30mL:10mL:8mmol.

[0024] In one embodiment of the present invention, in step (A2), during the reaction, the temperature is 70 to 80° C. and the time is 66 to 78 h;

[0025] Preferably, in step (A2), during the reaction, the temperature is 75° C. and the reaction time is 72 h.

[0026] In one embodiment of the present invention, in step (A3), FeCl 2 ·4H 2 The dosage ratio of O, ethylene glycol and BTA is 2-3 mmol: 50 mL: 2-3 mmol;

[0027] Preferably, FeCl 2 ·4H 2 The dosage ratio of O, ethylene glycol and BTA is 2.3mmol:50mL:2.3mmol;

[0028] During the reaction, the temperature is 160°C-220°C and the reaction time is 12-36h;

[0029] Preferably, during the reaction, the temperature is 200° C. and the reaction time is 24 h.

[0030] The second object of the present invention is to provide a polymer having dual redox properties prepared by the above method, wherein the oxidation of the triphenylamine unit in the polymer can reduce the energy band gap of the polymer, making the transition of charge carriers relatively easy, thereby promoting the redox process of the terpyridine-iron coordination unit.

[0031] The third object of the present invention is to provide a polymer resistive memory device with dual redox characteristics, wherein the polymer resistive memory device comprises a bottom electrode, an active layer and a top electrode from bottom to top;

[0032] The bottom electrode is a conductive metal oxide;

[0033] The active layer is a dual redox polymer poly(BTA-Fe) with a thickness of 20 to 150 nm;

[0034] The top electrode is a conductive metal with a thickness of 50 to 200 nm;

[0035] The polymer resistive random access memory with dual redox properties has non-volatile erasable storage performance; by applying different voltages, the resistance of the device changes, which can correspond to the binary conversion from "0" to "1" during the information storage process, and thus has an information storage function.

[0036] A fourth object of the present invention is to provide a method for preparing a polymer resistive memory device having dual redox characteristics, comprising the following steps:

[0037] (S1) pre-treating the conductive metal oxide / glass substrate and then subjecting it to oxygen plasma treatment;

[0038] (S2) after step (S1), the poly(BTA-Fe) solution is prepared into a thin film on a conductive metal oxide / glass substrate by liquid phase spin coating;

[0039] (S3) After step (S2) is completed, a metal electrode is grown on the surface of the film by thermal evaporation or magnetron sputtering to obtain a resistive memory device with a sandwich structure.

[0040] In one embodiment of the present invention, in step (S1), the pretreatment is ultrasonic cleaning in ethanol, acetone and isopropanol in sequence.

[0041] In one embodiment of the present invention, in step (S2), after the liquid phase spin coating is completed, it is placed in a vacuum oven for drying.

[0042] A fifth object of the present invention is to provide a polymer resistive memory device with dual redox characteristics for use in the field of information storage.

[0043] A method for using a polymer resistive memory device with dual redox characteristics in information storage comprises the following steps:

[0044] A -3V voltage is applied to the top electrode of the device, and the device switches from the off state to the on state; then a 4V voltage is applied to the top electrode of the device, and the device returns from the on state to the off state.

[0045] This resistance switching behavior can correspond to the binary conversion from "0" to "1" during information storage, thus having the function of information storage. In addition, the device has a small turn-on voltage and stable switching cycle characteristics, which will be able to improve the accuracy of information storage and logic operation processes.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The oxidation of the triphenylamine unit in the polymer having dual redox properties of the present invention can reduce the energy band gap of the polymer, making the transition of charge carriers relatively easy, thereby promoting the redox process of the terpyridine-iron coordination unit.

[0048] (2) The polymer resistive random access memory device with dual redox properties of the present invention has stable non-volatile erasable storage performance. During continuous testing, the changes in its on and off voltages are small, which can meet the application requirements in the fields of information storage and logical operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 AFM image of poly(BTA-Fe) film.

[0050] Figure 2 CH for BTA 2 Cl 2 UV-visible absorption spectra of solution and poly(BTA-Fe) film.

[0051] Figure 3 (a) Schematic diagram of the structure of the Al / poly(BTA-Fe) / ITO device; (b) the current-voltage (IV) characteristic curve of the device; (c) the distribution diagram of the turn-on voltage and the turn-off voltage; (d) the distribution diagram of the turn-on current and the turn-off current (reading voltage -0.1V).

[0052] Figure 4 (a) Current stability of the device under -0.1 V continuous reading voltage; (b) Current stability of the device under -0.1 V pulse voltage reading. DETAILED DESCRIPTION

[0053] The present invention provides a method for preparing a polymer having dual redox properties, wherein the polymer is poly(BTA-Fe), and the preparation method comprises the following steps:

[0054] (A1) Synthesis of M1: Sodium hydroxide, ethanol and 2-acetylpyridine were mixed, and then 4-formylphenylboronic acid and ammonia water were added. After the primary reaction, the mixture was heated for a secondary reaction, and post-treatment was performed to obtain a white solid M1.

[0055] (A2) Synthesis of BTA: M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2O, tert-butyl alcohol and M1 obtained in step (A1) are mixed and reacted, and post-treated to obtain green solid BTA;

[0056] (A3) Synthesis of poly(BTA-Fe): FeCl 2 ·4H 2 O, ethylene glycol and the BTA prepared in step (A2) are mixed and reacted, and then post-treated to obtain a dark brown solid poly(BTA-Fe);

[0057] Wherein, the chemical structural formula of M1 is shown in formula (I), and the chemical structural formula of M2 is shown in formula (II);

[0058]

[0059] Step (A2) and step (A3) are carried out in an inert atmosphere.

[0060] In one embodiment of the present invention, in step (A1), the usage ratio of sodium hydroxide, ethanol, 2-acetylpyridine, 4-formylphenylboronic acid and aqueous ammonia is 22.5 g: 300 mL: 18 mL-25 mL: 10-12 g: 150 mL;

[0061] Preferably, the usage ratio of sodium hydroxide, ethanol, 2-acetylpyridine, 4-formylphenylboronic acid and ammonia water is 22.5 g: 300 mL: 21 mL: 11.2 g: 150 mL.

[0062] In one embodiment of the present invention, in step (A1), during the first reaction, the temperature is 35 to 45° C. and the time is 5 to 7 h;

[0063] During the secondary reaction, the temperature is 80-100°C and the time is 22-26h;

[0064] Preferably, in step (A1), during one reaction, the temperature is 40° C. and the time is 6 h;

[0065] During the secondary reaction, the temperature was 90°C and the time was 24h.

[0066] In one embodiment of the present invention, in step (A2), M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2 O, the dosage ratio of tert-butyl alcohol to M1 is 3-4mmol: 0.30mmol: 24mmol: 80mL: 30mL: 10mL: 7-9mmol;

[0067] Preferably, M2, Pd(PPh 3 ) 2 Cl2 , sodium carbonate, toluene, H 2 The ratio of O, tert-butyl alcohol and M1 is 3.5mmol:0.30mmol:24mmol:80mL:30mL:10mL:8mmol.

[0068] In one embodiment of the present invention, in step (A2), during the reaction, the temperature is 70 to 80° C. and the time is 66 to 78 h;

[0069] Preferably, in step (A2), during the reaction, the temperature is 75° C. and the reaction time is 72 h.

[0070] In one embodiment of the present invention, in step (A3), FeCl 2 ·4H 2 The dosage ratio of O, ethylene glycol and BTA is 2-3 mmol: 50 mL: 2-3 mmol;

[0071] Preferably, FeCl 2 ·4H 2 The dosage ratio of O, ethylene glycol and BTA is 2.3mmol:50mL:2.3mmol;

[0072] During the reaction, the temperature is 160°C-220°C and the reaction time is 12-36h;

[0073] Preferably, during the reaction, the temperature is 200° C. and the reaction time is 24 h.

[0074] The invention provides a polymer with dual redox properties prepared by the method, wherein oxidation of the triphenylamine unit in the polymer can reduce the energy band gap of the polymer, making the transition of charge carriers relatively easy, thereby promoting the redox process of the terpyridine-iron coordination unit.

[0075] The present invention provides a polymer resistive memory device with dual redox characteristics, the polymer resistive memory device comprising a bottom electrode, an active layer and a top electrode from bottom to top;

[0076] The bottom electrode is a conductive metal oxide;

[0077] The active layer is a dual redox polymer poly(BTA-Fe) with a thickness of 20 to 150 nm;

[0078] The top electrode is a conductive metal with a thickness of 50 to 200 nm;

[0079] The polymer resistive random access memory with dual redox properties has non-volatile erasable storage performance; by applying different voltages, the resistance of the device changes, which can correspond to the binary conversion from "0" to "1" during the information storage process, and thus has an information storage function.

[0080] The present invention provides a method for preparing a polymer resistive memory device with dual redox characteristics, comprising the following steps:

[0081] (S1) pre-treating the conductive metal oxide / glass substrate and then subjecting it to oxygen plasma treatment;

[0082] (S2) after step (S1), the poly(BTA-Fe) solution is prepared into a thin film on a conductive metal oxide / glass substrate by liquid phase spin coating;

[0083] (S3) After step (S2) is completed, a metal electrode is grown on the surface of the film by thermal evaporation or magnetron sputtering to obtain a resistive memory device with a sandwich structure.

[0084] Furthermore, in step (S1), the pretreatment is ultrasonic cleaning in ethanol, acetone and isopropanol in sequence.

[0085] Furthermore, in step (S2), after the liquid phase spin coating is completed, it is placed in a vacuum oven for drying.

[0086] The invention provides an application of a polymer resistive memory device with dual redox characteristics in the field of information storage.

[0087] A method for using a polymer resistive memory device with dual redox characteristics in information storage comprises the following steps:

[0088] A -3V voltage is applied to the top electrode of the device, and the device switches from the off state to the on state; then a 4V voltage is applied to the top electrode of the device, and the device returns from the on state to the off state.

[0089] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0090] In the following examples, unless otherwise specified, all reagents used are commercially available reagents, and all detection means and methods used are conventional detection means and methods in the art.

[0091] Example 1

[0092] This embodiment provides a polymer with dual redox properties and a preparation method thereof, and the schematic diagram of the preparation process is as follows:

[0093]

[0094] The details are as follows:

[0095] (A1) Synthesis of M1: Sodium hydroxide (22.5 g, 0.56 mol), ethanol (300 mL) and 2-acetylpyridine (21 mL, 22.7 g) were added to a reaction flask and stirred at 40°C for 20 minutes; then 4-formylphenylboronic acid (11.2 g, 74.67 mmol) and aqueous ammonia (37%, 150 mL) were added and stirred at 40°C for 6 hours, then heated to 90°C and continued to react for 24 hours; then the mixture was cooled, filtered and the solid was collected, and the obtained solid was washed with water and CH 2 Cl 2 After repeated washing and drying (24 hours), a white solid was obtained.

[0096] (A2) Synthesis of BTA: Under argon atmosphere, M1 (2.82 g, 8 mmol), M2 (1.41 g, 3.5 mmol), Pd (PPh 3 ) 2 Cl 2 (210.60 mg, 0.30 mmol), sodium carbonate (2.54 g, 24 mmol), toluene (80 mL), H 2 O (30 mL) and tert-butyl alcohol (10 mL); the mixture was then refluxed at 75 ° C for 72 hours; after the mixture was cooled, CHCl 3 Extract 3 times; combine the organic phases and wash with brine, then dry over anhydrous sodium sulfate and filter; concentrate the filtrate by rotary evaporation, purify by column chromatography, and then recrystallize with MeOH to finally obtain a green solid:

[0097] (A3) Synthesis of poly(BTA-Fe): BTA (2 g, 2.3 mmol), FeCl 2 ·4H 2 O (460 mg, 2.3 mmol) and ethylene glycol (50 mL); then, the mixture was refluxed at 200 ° C for 24 hours; after the mixture was cooled, the insoluble matter was filtered out and the filtrate was collected, and the solvent was removed under reduced pressure to obtain a dark brown solid: poly (BTA-Fe).

[0098] The dual redox polymer contains two redox units: triphenylamine and terpyridine-iron. The first redox reaction is due to the conversion of triphenylamine (TPA) to polar TPA (TPA ·+ ) is caused by the reversible transformation, and the second redox reaction is caused by the metal center Fe 2+ / Fe 3+ Caused by reversible transformation (as shown below);

[0099]

[0100] Where n is 10 2 -10 4 A positive integer.

[0101] Atomic force microscopy (AFM) images Figure 1 As shown, through Figure 1 It can be found that the prepared poly(BTA-Fe) film has a smooth and uniform surface;

[0102] BTA CH 2 Cl 2 The UV-visible absorption spectra of the solution and poly(BTA-Fe) are shown in Figure 2 As shown, through Figure 2 It can be found that the UV-visible spectrum of BTA has a strong absorption peak at 374nm, which can be attributed to the π-π* transition. 2+ After complexation to form poly(BTA-Fe), poly(BTA-Fe) shows a new strong absorption peak at 580nm, which is caused by the metal (Fe 2+ ) to the ligand (BTA), indicating that BTA and Fe 2+ Poly(BTA-Fe) was generated through coordination reaction.

[0103] Example 2

[0104] This embodiment provides a polymer resistive memory device with dual redox characteristics and a preparation method thereof, comprising the following steps:

[0105] (S1) ITO was ultrasonically cleaned in ethanol, acetone, and isopropanol for 15 min, and then treated with oxygen plasma;

[0106] (S2) preparing a 100 nm thick film on a substrate by liquid spin coating of a 5 mg / mL poly(BTA-Fe) solution (dissolved in N,N-dimethylformamide), and then drying in a vacuum oven;

[0107] (S3) Al with a thickness of 100 nm is thermally evaporated on the surface of the active layer to obtain a resistive memory device with a sandwich structure.

[0108] The electrical properties of the Al / poly(BTA-Fe) / ITO device prepared above were studied directly on Keithley 4200 without any packaging ( Figure 3 a). In the 200-cycle continuous voltage sweep test, the devices all showed non-volatile erasable storage performance ( Figure 3b), since this resistance switching behavior can correspond to the binary conversion from "0" to "1" during information storage, the device has information storage function. Based on the 200 test data, statistical analysis shows that the changes in the on / off voltage and on / off current are very small ( Figure 3 c and 3d), which indicates that the device has good on-off switching cycle stability under continuous testing.

[0109] Furthermore, the stability of the device was studied by constant voltage and pulse tests ( Figure 4 a and 4b). Figure 3 a and 3b, it can be found that the device has a constant voltage of more than 8 hours and a 6 After reading a series of continuous pulses, there is no obvious attenuation of the on and off currents, which proves that the device has good performance stability.

[0110] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a polymer having dual redox properties, It is characterized in that The polymer is poly(BTA-Fe), and its preparation method comprises the following steps: (A1) Synthesis of M1: Sodium hydroxide, ethanol and 2-acetylpyridine were mixed, and then 4-formylphenylboronic acid and ammonia water were added. After the primary reaction, the mixture was heated for a secondary reaction, and post-treatment was performed to obtain a white solid M1. (A2) Synthesis of BTA: M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2 O, tert-butyl alcohol and M1 obtained in step (A1) are mixed and reacted, and post-treated to obtain green solid BTA; (A3) Synthesis of poly(BTA-Fe): FeCl 2 ·4H 2 O, ethylene glycol and the BTA prepared in step (A2) are mixed and reacted, and then post-treated to obtain a dark brown solid poly(BTA-Fe); Wherein, the chemical structural formula of M1 is shown in formula (I), and the chemical structural formula of M2 is shown in formula (II); Step (A2) and step (A3) are carried out in an inert atmosphere.

2. A method for preparing a polymer having dual redox properties according to claim 1, It is characterized in that In step (A1), the usage ratio of sodium hydroxide, ethanol, 2-acetylpyridine, 4-formylphenylboronic acid and aqueous ammonia is 22.5 g:300 mL:18 mL-25 mL:10-12 g:150 mL.

3. The method for preparing a polymer having dual redox properties according to claim 1, It is characterized in that In step (A1), during the primary reaction, the temperature is 35-45°C and the time is 5-7h; During the secondary reaction, the temperature is 80-100°C and the time is 22-26 hours.

4. The method for preparing a polymer having dual redox properties according to claim 1, It is characterized in that In step (A2), M2, Pd(PPh 3 ) 2 Cl 2 , sodium carbonate, toluene, H 2 The usage ratio of O, tert-butanol and M1 is 3-4mmol: 0.30mmol: 24mmol: 80mL: 30mL: 10mL: 7-9mmol.

5. The method for preparing a polymer having dual redox properties according to claim 1, It is characterized in that In step (A2), during the reaction, the temperature is 70-80° C. and the reaction time is 66-78 hours.

6. The method for preparing a polymer having dual redox properties according to claim 1, It is characterized in that In step (A3), FeCl 2 ·4H 2 The dosage ratio of O, ethylene glycol and BTA is 2-3 mmol: 50 mL: 2-3 mmol; During the reaction, the temperature is 160°C-220°C and the time is 12 to 36 hours.

7. A polymer having dual redox properties prepared by the method according to any one of claims 1 to 6.

8. A polymer resistive memory device with dual redox characteristics, It is characterized in that The polymer resistive memory device comprises a bottom electrode, an active layer and a top electrode from bottom to top; The bottom electrode is a conductive metal oxide; The active layer is a dual redox polymer as claimed in claim 7 with a thickness of 20 to 150 nm: poly(BTA-Fe); The top electrode is a conductive metal with a thickness of 50 to 200 nm.

9. A method for preparing a polymer resistive memory device having dual redox characteristics as claimed in claim 8, It is characterized in that The following steps are involved: (S1) pre-treating the conductive metal oxide / glass substrate and then subjecting it to oxygen plasma treatment; (S2) after step (S1), the poly(BTA-Fe) solution is prepared into a thin film on a conductive metal oxide / glass substrate by liquid phase spin coating; (S3) After step (S2) is completed, a metal electrode is grown on the surface of the film by thermal evaporation or magnetron sputtering to obtain a resistive memory device with a sandwich structure.

10. An application of the polymer resistive memory device with dual redox characteristics as claimed in claim 8 in the field of information storage.

Images