An intrinsic ion gate metal halide perovskite diode and a preparation method thereof

Abstract

The present invention provides an intrinsic ion-gate metal halide perovskite diode and a preparation method thereof, which adopts a planar heterostructure and sequentially includes a glass substrate layer, a transparent electrode layer, a polystyrene sulfonate (PEDOT:PSS) layer, a perovskite layer and a metal electrode layer; the application of this technical solution can realize that in the antisymmetric saturation region, the ion-gate diode exhibits stable multi-value response characteristics to electric pulses and light pulses. This enables the device to handle optoelectronic logic calculations beyond binary logic. At the same time, at low voltages, the device exhibits a controllable plastic response to electric and light pulses. The time scale of this ion-dependent plasticity is similar to the short-term plasticity of synapses, which enables the device to realize brain-like computing and neuromorphic computing functions.

Description

Technical Field

[0001] The invention relates to the field of technical diodes, in particular to an intrinsic ion-gate metal halide perovskite diode and a preparation method thereof. Background Art

[0002] Metal halide perovskites are an emerging class of semiconductor materials with excellent optoelectronic properties. They have shown great potential in the development of next-generation high-performance optoelectronic devices and have received extensive research and attention. At present, the performance of perovskite photovoltaic devices and light-emitting diodes has been greatly improved. They not only show their good optoelectronic properties, but also have simple and mature processing technologies. However, it is still challenging to apply metal halide perovskite semiconductors to the field of information processing. The main reason is that the complex effect of ion migration in metal halide perovskite materials weakens the modulation of information processing components on the signal on the gate, limiting the development of components. In three-terminal perovskite field-effect transistors, the ion distribution shields the applied voltage, greatly weakening the gate's charge modulation in the conductive channel. Similarly, in two-terminal devices with metal-insulator-metal structures, due to the direct contact between the perovskite and metal electrodes, ion migration is intertwined with charge injection and interface chemistry, which leads to unsustainable modulation of the device by voltage stimulation, limiting the application of such devices in neuromorphic computing. Therefore, the development of new diodes based on metal halide perovskites remains key to information processing technologies such as low-voltage low-voltage logic circuits and neuromorphic computing.

[0003] Currently, new diodes based on metal halide perovskites are being developed to precisely regulate the conductance of perovskite devices for use in information processing technology solutions such as low-voltage logic circuits and neuromorphic computing, including the following:

[0004] (1) Metal-organic halide perovskite devices with highly efficient switchable photovoltaic effect. Based on metal halide perovskites, they have vertical and lateral photovoltaic structures. The direction of the photocurrent of this type of device can be repeatedly switched by applying a small electric field. The state of the device can be read not only with electric pulses, but also with optical pulses, paving the way for new methods of electric pulse doping perovskite semiconductors. It provides a new method for manufacturing memristor arrays and developing new optoelectronic computing devices.

[0005] (2) Two-terminal organic metal halide perovskite synaptic devices. This device has a typical metal-semiconductor-metal (MSM) structure. For example, the perovskite layer is sandwiched between poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) covered indium tin oxide (ITO) electrodes and gold (Au) clicks. This type of device can simulate neuromorphic learning and memory processes, such as pulse interval dependent plasticity (STDP), pulse rate dependent plasticity (SRDP), short-term plasticity (STP) and long-term potentiation (LTP) as well as learning experience behaviors.

[0006] (3) Organic lead halide perovskite memory. In this type of device, the perovskite layer is in direct contact with the top and bottom electrodes, such as ITO / PEI / CH3NH3PbI3 / PEI / metal. The memory switching effect of this type of device originates from the synergistic effect of defect movement and metal ions in the perovskite film, such as interface regulation, the formation and fusing of metal conductive filaments, etc.

[0007] Existing metal halide information processing devices have the following main disadvantages:

[0008] (i) The processes of ions, photogenerated charges, perovskite / metal contact, and charge injection are entangled with each other, which makes it difficult for the device to produce a simple and regular response to external stimuli.

[0009] (ii) These devices usually operate in an unstable voltage region (V > 1 V) and are not easy to produce a stable, quantitative, and controllable response. Summary of the invention

[0010] In view of this, the object of the present invention is to provide an intrinsic ion gate metal halide perovskite diode and a method for preparing the same, wherein the ion gate diode exhibits stable multi-value response characteristics to electrical pulses and optical pulses in the antisymmetric saturation region. This enables the device to handle optoelectronic logic calculations beyond binary logic. At the same time, the device exhibits controllable plastic response to electrical and optical pulses at low voltages. The time scale of this ion-dependent plasticity is similar to the short-term plasticity of synapses, which enables the device to achieve brain-like computing and neuromorphic computing functions.

[0011] To achieve the above-mentioned object, the present invention adopts the following technical scheme: an intrinsic ion-gate metal halide perovskite diode and a preparation method thereof, adopting a planar heterostructure, which sequentially comprises a glass substrate layer, a transparent electrode layer, a polystyrene sulfonate (PEDOT:PSS) layer, a perovskite layer and a metal electrode layer;

[0012] The preparation method comprises the following steps:

[0013] Step 1, preparation of a precursor solution; lead iodide (PbI2) and methyl ammonium iodide (MAI) are dissolved in 1 mL of an ionic liquid at a ratio of 297.44±20 mg and 102.56±10 mg, respectively, to form a mixture; then, in a nitrogen environment in a glove box, the mixture is stirred at 60° C. for 6 hours to prepare a perovskite precursor solution; the perovskite precursor solution is transferred to an air environment for preparing a thin film;

[0014] Step 2, preparation of a polystyrene sulfonate (PEDOT:PSS) layer; dropping a PEDOT:PSS aqueous solution on the transparent electrode layer, spinning the PEDOT:PSS at a speed of 5000 rpm for 50 seconds, and annealing at 120°C for 30 minutes, annealing on a heated substrate, or in an oven at 120°C;

[0015] Step 3, spin coating and annealing of the perovskite film; first, clean the transparent electrode layer and the glass substrate layer with alcohol, detergent and deionized water; clean the transparent electrode layer and the glass substrate layer with continuous ultrasonic cleaning in alcohol, detergent, deionized water and alcohol in turn, and then expose them to ultraviolet ozone for 10 minutes; then preheat the transparent electrode layer and the glass substrate layer for 3 minutes, and the preheating temperature is 95±5°C; then the perovskite precursor solution is spin coated at a speed of 4000 rpm for 20 seconds, and then annealed at 100°C for 3 to 4 minutes;

[0016] Step 4: Preparation of metal electrode layer; -4 Under a pressure of pa, Bi was evaporated by vacuum hot coating technology with an evaporation rate of 0.1 Å / s and a deposition thickness of 1300 Å; or Bi and Au were evaporated with evaporation rates of 0.1 Å / s and 2 Å / s, and deposition thicknesses of 200 Å and 800 Å, respectively.

[0017] In a preferred embodiment, the transparent electrode layer is made of indium tin oxide (ITO) conductive glass.

[0018] In a preferred embodiment, the ionic liquid is composed of methylamine acetate (MAAc) or methylamine formate (MAFa) solution.

[0019] In a preferred embodiment, the perovskite layer is an organic-inorganic hybrid perovskite material methylamine lead iodide (MAPbI3).

[0020] In a preferred embodiment, an ion gate diode model of a metal halide perovskite diode is established; ion movement, electric field redistribution and photocurrent output are simulated; wherein the response of the photocurrent to the external voltage is established by a simple photodiode model, and the model J is:

[0021]

[0022] In the model, q is the elementary charge, k B is the Boltzmann constant, T is the temperature; positive and negative ions are only distributed at the left and right ends of the region with a length of L in the perovskite, and they are allowed to jump from one end to the other; the total amount of ions is N0, and the ion-induced voltage is V N , the maximum ion induction voltage is The induced voltage generated by ion polarization offsets the external voltage; the time for ions to move from one end to the other is t = L / μE, which is the mobility of μ ions, and the electric field is considered to be uniformly distributed; the rate change of the number of positive ions on the left is expressed as

[0023]

[0024] Where α=μ / L 2 ;The voltage across the device is:

[0025]

[0026] Where V app is the applied voltage, V bi It is the built-in voltage.

[0027] In a preferred embodiment, the metal halide perovskite diode is used for multi-valued optoelectronic logic calculation that breaks through binary logic calculation.

[0028] In a preferred embodiment, the metal halide perovskite diode is used for brain-like computing and neuromorphic computing.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the antisymmetric saturation region, the ion gate diode exhibits stable multi-value response characteristics to electrical pulses and optical pulses. This enables the device to handle optoelectronic logic calculations beyond binary logic. At the same time, the device exhibits controllable plastic response to electrical and optical pulses at low voltages. We emphasize that the time scale of this ion-dependent plasticity is similar to the short-term plasticity of synapses, which enables the device to realize brain-like computing and neuromorphic computing functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of an intrinsic ion gate metal halide perovskite diode in a preferred embodiment of the present invention;

[0032] Figure 2 Schematic diagram of the preparation of a precursor solution in a preferred embodiment of the present invention;

[0033] Figure 3It is a schematic diagram of the preparation process of an intrinsic ion gate metal halide perovskite diode in a preferred embodiment of the present invention;

[0034] Figure 4 1 is a bidirectional plastic antisymmetric photocurrent curve (I) of a metal halide perovskite diode in a preferred embodiment of the present invention;

[0035] Figure 5 The bidirectional plastic antisymmetric photocurrent curve (II) of the metal halide perovskite diode in the preferred embodiment of the present invention;

[0036] Figure 6 The bidirectional plastic antisymmetric photocurrent curve of the metal halide perovskite diode in the preferred embodiment of the present invention (III)

[0037] Figure 7 The regular plasticity accurate simulation curve (I) of the photocurrent of the metal halide perovskite diode in the preferred embodiment of the present invention;

[0038] Figure 8 The regular plasticity accurate simulation curve (II) of the photocurrent of the metal halide perovskite diode in the preferred embodiment of the present invention;

[0039] Fig. 9 It is an accurate simulation curve of the photoelectric pulse response of the metal halide perovskite diode in the preferred embodiment of the present invention;

[0040] Fig.10 The stable response curve (I) of the metal halide perovskite diode to electric pulses and light pulses in the preferred embodiment of the present invention;

[0041] Fig.11 The stable response curve (II) of the metal halide perovskite diode to electric pulses and light pulses in the preferred embodiment of the present invention;

[0042] Fig.12 The performance curve (I) of the vertical “phototransistor” realized by the metal halide perovskite diode in the preferred embodiment of the present invention;

[0043] Fig.13 Performance curve (II) of a vertical “phototransistor” realized by a metal halide perovskite diode in a preferred embodiment of the present invention;

[0044] Fig.14 Logic gate curve (I) for realizing natural number summation and subtraction by metal halide perovskite diode in a preferred embodiment of the present invention;

[0045] Fig.15 Logic gate curve (II) for realizing natural number summation and subtraction by metal halide perovskite diode in a preferred embodiment of the present invention;

[0046] Fig.16 Logic gate curve (III) for realizing natural number summation and subtraction by metal halide perovskite diode in a preferred embodiment of the present invention;

[0047] Fig.17 1 is a plasticity response curve (I) of a metal halide perovskite diode to electrical and optical pulses in a preferred embodiment of the present invention;

[0048] Fig.18 The plasticity response curve (II) of the metal halide perovskite diode to electrical and optical pulses in the preferred embodiment of the present invention;

[0049] Fig.19 The plasticity response curve (III) of the metal halide perovskite diode to electrical and optical pulses in the preferred embodiment of the present invention;

[0050] Fig. 20 The synaptic function curve (I) of the metal halide perovskite diode realizing paired pulse facilitation (PPF) and paired pulse depression (PPD) in the preferred embodiment of the present invention;

[0051] Fig.21 The synaptic function curve (II) of the metal halide perovskite diode realizing paired pulse facilitation (PPF) and paired pulse depression (PPD) in the preferred embodiment of the present invention;

[0052] Fig. 22 The synaptic function curve (III) of the metal halide perovskite diode realizing paired pulse facilitation (PPF) and paired pulse depression (PPD) in the preferred embodiment of the present invention;

[0053] Fig.23 Schematic diagram of a comparison case of a device with or without a Bi layer in a preferred embodiment of the present invention;

[0054] Fig.24 A schematic diagram of a comparison case with and without a noble metal electrode device in a preferred embodiment of the present invention;

[0055] Fig.25 A schematic diagram showing the comparison of cases with and without an electron transport layer in a preferred embodiment of the present invention;

[0056] Fig.26 A schematic diagram showing the comparison of cases with and without active metal electrodes in a preferred embodiment of the present invention;

[0057] Fig. 27 Schematic diagram of the effect of the thickness of the perovskite film on the device performance in a preferred embodiment of the present invention;

[0058] Fig.28 Schematic diagram of the effect of Bi layer thickness on device performance in a preferred embodiment of the present invention;

[0059] Fig.29 This is a schematic diagram of the influence of material components on the device in a preferred embodiment of the present invention;

[0060] Fig.30 Schematic diagram of the effect of the wavelength of the excitation light pulse on the device in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0061] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0062] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0063] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0064] An intrinsic ion-gate metal halide perovskite diode and a method for preparing the same, referring to Figure 1 , adopts a planar heterostructure, which includes a glass substrate layer, a transparent electrode layer, a polystyrene sulfonate (PEDOT:PSS) layer, a perovskite layer and a metal electrode layer in sequence; the perovskite layer converts photons into electrons and holes in the device, and its photoelectric properties play a key role in the properties of the battery. The perovskite layer used in the present invention is an organic-inorganic hybrid perovskite material methylamine lead iodide (MAPbI3).

[0065] refer to Figures 2 to 3 , the preparation method comprises the following steps:

[0066] Step 1, preparation of a precursor solution; lead iodide (PbI2) and methyl ammonium iodide (MAI) are dissolved in 1 mL of an ionic liquid at a ratio of 297.44±20 mg and 102.56±10 mg, respectively, to form a mixture; then, in a nitrogen environment in a glove box, the mixture is stirred at 60° C. for 6 hours to prepare a perovskite precursor solution; the perovskite precursor solution is transferred to an air environment for preparing a thin film;

[0067] Step 2, preparation of a polystyrene sulfonate (PEDOT:PSS) layer; drop a PEDOT:PSS aqueous solution on the transparent electrode layer, spin the PEDOT:PSS at a speed of 5000 rpm for 50s, and anneal at 120°C for 30 minutes, annealing on a heated substrate or in an oven at 120°C; the thickness of the polystyrene sulfonate (PEDOT:PSS) layer is determined by the material and the spin coating speed during the preparation process.

[0068] Step 3, spin coating and annealing of the perovskite film; first, clean the transparent electrode layer and the glass substrate layer with alcohol, detergent and deionized water; clean the transparent electrode layer and the glass substrate layer with continuous ultrasonic cleaning in alcohol, detergent, deionized water and alcohol in turn, and then expose them to ultraviolet ozone for 10 minutes; then preheat the transparent electrode layer and the glass substrate layer for 3 minutes, and the preheating temperature is 95±5°C; then the perovskite precursor solution is spin coated at a speed of 4000 rpm for 20 seconds, and then annealed at 100°C for 3 to 4 minutes;

[0069] Step 4: Preparation of metal electrode layer; -4 Under a pressure of pa, Bi was evaporated by vacuum hot coating technology with an evaporation rate of 0.1 Å / s and a deposition thickness of 1300 Å; or Bi and Au were evaporated with evaporation rates of 0.1 Å / s and 2 Å / s, and deposition thicknesses of 200 Å and 800 Å, respectively.

[0070] The transparent electrode layer is made of indium tin oxide (ITO) conductive glass.

[0071] The component of the ionic liquid is methylamine acetate (MAAc) or methylamine formate (MAFa) solution.

[0072] like Figure 4 As shown in Figure 1, the bidirectional plastic antisymmetric photocurrent curve of the metal halide perovskite diode. The current-voltage curve is divided into a stable reverse saturation asymmetric region and a plastic hysteresis region. The saturation photocurrent of the metal halide perovskite diode is between 10 and 100 mW / cm 2 is proportional to the light intensity ( Figure 5 ). This shows that metal halide perovskite diodes can be precisely modulated by multiple beam pulses and photocurrent. In addition, metal halide perovskite diodes have regular plasticity to the size of electrical pulses, operation history, and voltage sweep range. Figure 4 As shown, the device was characterized at different voltage scan rates, and the results showed that the voltage scan rate had a significant effect on the range of the hysteresis region. Under pulse excitation at a fast scan rate (1V / s), the device was relatively stable, while under stimulation at a slow scan rate (0.01V / s), the device had greater plasticity. This shows that the device can be adjusted by the speed and intensity of the external voltage pulse.

[0073] The ion-gate diode model of the metal halide perovskite diode is established; the ion movement, electric field redistribution and photocurrent output are simulated; the response of the photocurrent to the external voltage is established by a simple photodiode model, and the model J is:

[0074]

[0075] In the model, q is the elementary charge, k B is the Boltzmann constant, T is the temperature; positive and negative ions are only distributed at the left and right ends of the region with a length of L in the perovskite, and they are allowed to jump from one end to the other; the total amount of ions is N0, and the ion-induced voltage is V N , the maximum ion induction voltage is The induced voltage generated by ion polarization offsets the external voltage; the time for ions to move from one end to the other is t = L / μE, which is the mobility of μ ions, and the electric field is considered to be uniformly distributed; the rate change of the number of positive ions on the left is expressed as

[0076]

[0077] Where α=μ / L 2 ;The voltage across the device is:

[0078]

[0079] Where V app is the applied voltage, V bi It is the built-in voltage.

[0080] 1) Accurate simulation of bidirectional plastic antisymmetric photocurrent curve of metal halide perovskite diode

[0081] like Figures 6 to 8 As shown, the model reproduces the main features of the bidirectional photocurrent. The ion-gate diode model shows that the ion distribution and electrical state of the device depend on the history of the voltage sweep and reveals that ions act as a regulatory mechanism for the device state.

[0082] 2) Accurate simulation of the regular plasticity of photocurrent in metal halide perovskite diodes

[0083] The model also reproduces the regular plasticity of the photocurrent, that is, the photocurrent is related to the size and history of the electric pulse, that is, the regular response of the device at different voltage scan rates and voltage ranges. It should be emphasized that based on the hysteresis effect of ion migration, the conductive state of the device can be adjusted by a voltage less than 1V.

[0084] 3) Accurate simulation of photoelectric pulse response of metal halide perovskite diodes

[0085] Fig. 9 The photocurrent response of the device to a series of voltage pulses is shown. The results show that the results of the ion-deleted diode model are consistent with the experimental data, indicating the dominant role of the ion gate in regulating the diode photoconductivity. We emphasize that the state of the device can be precisely controlled by the number, width and peak interval of the voltage pulses. This result shows the controllability of the device's photoelectric response to pulses, indicating the device's potential for application in optoelectronic information processing.

[0086] The rich and stable photoelectric response characteristics of the present invention give the device a variety of application scenarios and effects. In the antisymmetric saturation region, the ion gate diode exhibits stable multi-value response characteristics to electrical pulses and optical pulses. This enables the device to handle optoelectronic logic calculations beyond binary logic. At the same time, at low voltages, the device exhibits controllable plastic responses to electrical and optical pulses. We emphasize that the time scale of this ion-dependent plasticity is similar to the short-term plasticity of synapses, which enables the device to achieve brain-like computing and neuromorphic computing functions.

[0087] Stable response to electrical and optical pulses. The ion-gate diode exhibits a stable response to electrical and optical pulses. The bidirectional saturation region is independent of the scanning direction and scanning rate during the electrical characterization process, which makes the device have a faster and more stable response to external optical pulse stimulation. Fig.10 ,,The voltage values ​​of the electric pulses are set to –0.5V and 0.7V, so that the diode can operate at a low voltage of 1V and in a stable condition. Fig.11 The variation of the photocurrent with voltage pulses of frequencies 1–5000 Hz is shown. For higher frequencies (above 1000 Hz), we observe overshoots in the photocurrent and dark current that can be fitted by an exponential function with a time constant of ~2.8 μs. The capacitance of the diode limits the resolution time of the device for electrical pulses. By reducing the device area, the resolution time can be increased from 2.8 μs to 0.28 ps.

[0088] Achieve vertical "phototransistor" performance. The stable response of the device gives the device "phototransistor" performance. The switchable conductivity of the diode by light rather than gate voltage allows the device to operate like a phototransistor, with its simple structure, high efficiency and multi-valued logic operation. Fig.12 and Fig.13 As shown in the figure, a 100Hz periodic square voltage pulse (the high voltage and low voltage states are (0.7V, 0V) and (0V, –0.5V) are used as the electrical input, and a unit light intensity P0 is about 10mWcm –2 The device exhibits multi-value states and their anti-states, which enables the device to handle optoelectronic logic calculations beyond binary logic.

[0089] Logic gates that implement summation and subtraction of natural numbers. Fig.14 It is a logic gate application. Device 1 and device 2 are prepared on the same ITO substrate, and electrical and optical signals are applied to the corresponding components. It realizes the summation and difference of two optical inputs. Fig.15 , when the electrical pulses are the same, the photocurrent response corresponds to the sum of light pulse 1 and light pulse 2, and the sum operation of the two light pulses is implemented by the optoelectronic logic device. Fig.16 , when two electrical pulses are applied with opposite bias voltages (0.7V, –0.5V) and (–0.5V, 0.7V), the total photocurrent is the difference between the responses of the two components to the light pulses. The logic circuit implements the function of subtracting light input 2 from light input 1.

[0090] Plastic responses to electrical and optical pulses. Fig.17 As shown, when the device is stimulated by a -0.5V electric pulse, the photoconductivity state of the device at 0V exhibits regular plasticity, and the state of the device can be precisely controlled by the peak number, width and interval of the electric polarization pulse. Fig.18 It is shown that as the number of pulses increases, the photocurrent of the device at 0V gradually decreases and the polarity reverses. Fig.19 It shows that the photocurrent response is closely related to the time interval of the electrical pulse signal. The change in photocurrent density depends on the time interval between peaks (i.e., the pulse rate).

[0091] The synaptic functions of paired pulse facilitation (PPF) and paired pulse depression (PPD) are realized. This new type of photocurrent plasticity enables the device to be used as a basic electronic unit for artificial neuromorphic computing. Fig. 20 The application model of the display of neural synapses (electronic synapses) is shown. During operation, the electronic synapses are modulated by a series or a -0.5V voltage pulse, followed by a subsequent light pulse to read the state of the device. This allows the device to simulate the memory and forgetting functions of the brain ( Fig.21 ), paired pulse facilitation (PPF) and paired pulse depression (PPD) of synaptic function ( Fig. 22 ).

[0092] The following describes embodiments of the present invention and counterexamples:

[0093] (I) Comparison of devices with and without Bi layer

[0094] Fig.23 The photocurrent response curves of ITO / PEDOT:PSS / MAPbI3 / Au and ITO / PEDOT:PSS / MAPbI3 / Bi / Au devices are given respectively. It can be seen that by adding the Bi layer, the device prepared in this scheme has achieved a stable bidirectional plastic antisymmetric photocurrent curve.

[0095] (II) Comparison of devices with and without precious metal electrodes

[0096] In the process of device preparation, in this case, precious metals are evaporated outside the Bi layer, which will not affect the device performance. Fig.24 The photocurrent response curve of the device is given when a typical noble metal layer is evaporated outside the Bi layer. It can be seen from the figure that when Au is further evaporated on the Bi layer, the device performance remains stable.

[0097] (III) Comparison of cases with and without electron transport layer

[0098] Fig.25 ITO / PEDOT:PSS / MAPbI3 / C 60 / Bi / Au and ITO / PEDOT:PSS / MAPbI3 / Bi / Au devices. It can be seen that adding an electron transport layer (C 60 Etc.), the device prepared by this method has achieved a stable bidirectional plastic antisymmetric photocurrent curve will disappear.

[0099] (IV) Case comparison with and without active metal electrodes

[0100] During the device preparation process, active metals such as Cu, Ag, Al, etc. are evaporated outside the Bi layer in this case, which will affect the device performance. Fig.26 The photocurrent response curve of the device is given when a typical metal layer is evaporated outside the Bi layer. It can be seen from the figure that when Cu or Ag is further evaporated on the Bi layer, the device performance decreases significantly.

[0101] 5. Effect of perovskite film thickness on device performance

[0102] In the process of preparing the device, the thickness of the perovskite layer in this case is between 400nm and 800nm. If the thickness of the perovskite layer is changed beyond the given range, the device performance will be affected. Fig. 27 The photocurrent response curves of the device are given in different ranges of typical perovskite layer thickness. It can be seen from the figure that the device performance is significantly reduced when the perovskite layer thickness is less than 400nm. When the perovskite layer thickness is greater than or equal to 300nm and less than 800nm, stable device performance can be obtained.

[0103] (VI) Effect of Bi layer thickness on device performance

[0104] In the process of manufacturing the device, the thickness of the Bi layer in this case is between 20nm and 1000nm. If the thickness of the Bi layer is changed beyond the given range, the device performance will be affected. Fig.28The photocurrent response curves of the device are given in different ranges of Bi layer thickness. It can be seen from the figure that the device performance is significantly reduced when the Bi layer thickness is less than 20nm. When the Bi layer thickness is greater than or equal to 20nm and less than 1000nm, stable device performance can be obtained.

[0105] (VII) Effect of material composition on devices

[0106] In the process of preparing the device, in this case, PbI2, MAI, and MACl were dissolved in 1 mL of ionic liquid at a ratio of 297.44±20 mg and 102.56±10 mg respectively. If the weight and ratio of the components are changed beyond the given range, the device performance will be affected. Fig.29 The photocurrent response curve of the device is given when the ionic liquid precursor solution is prepared with different masses of PbI2. It can be seen from the figure that the ionic liquid precursor solution prepared with PbI2 within 297.44±20mg can obtain stable device performance. Beyond this range, the device performance decreases significantly.

[0107] 8. Effect of excitation light pulse wavelength on the device

[0108] Ion-gate metal halide perovskite diodes have the same photocurrent response under 450, 532, and 650 nm monochromatic light illumination ( Fig.30 ), the photocurrent response characteristics of the device are independent of the light wavelength due to the high absorption coefficient of light from the ultraviolet to the near-infrared.

Claims

1. A method for preparing an intrinsic ion-gate metal halide perovskite diode, characterized in that A planar heterostructure is used, which includes a glass substrate layer, a transparent electrode layer, a polystyrene sulfonate (PEDOT:PSS) layer, a perovskite layer and a metal electrode layer in sequence; The preparation method comprises the following steps: Step 1, preparation of a precursor solution; lead iodide (PbI2) and methyl ammonium iodide (MAI) are dissolved in 1 mL of an ionic liquid at a ratio of 297.44±20 mg and 102.56±10 mg, respectively, to form a mixture; then, in a nitrogen environment in a glove box, the mixture is stirred at 60° C. for 6 hours to prepare a perovskite precursor solution; the perovskite precursor solution is transferred to an air environment for preparing a thin film; Step 2, preparation of a polystyrene sulfonate (PEDOT:PSS) layer; dropping an aqueous solution of polystyrene sulfonate (PEDOT:PSS) on the transparent electrode layer, rotating the aqueous solution of polystyrene sulfonate (PEDOT:PSS) at a speed of 5000 rpm for 50 seconds, and annealing at 120°C for 30 minutes, annealing on a heated substrate or in an oven at 120°C; Step 3, spin coating and annealing of the perovskite film; first, clean the transparent electrode layer and the glass substrate layer with alcohol, detergent and deionized water; clean the transparent electrode layer and the glass substrate layer with continuous ultrasonic cleaning in alcohol, detergent, deionized water and alcohol in turn, and then expose them to ultraviolet ozone for 10 minutes; then preheat the transparent electrode layer and the glass substrate layer for 3 minutes, and the preheating temperature is 95±5°C; then the perovskite precursor solution is spin coated at a speed of 4000 rpm for 20 seconds, and then annealed at 100°C for 3 to 4 minutes; Step 4: Preparation of metal electrode layer; -4 Under a pressure of pa, Bi was evaporated by vacuum thermal coating technology at an evaporation rate of 0.1 angstroms / second and a deposition thickness of 1300 angstroms; or Bi and Au were evaporated at evaporation rates of 0.1 angstroms / second and 2 angstroms / second, respectively, and the deposition thicknesses were 200 angstroms and 800 angstroms, respectively; The ion-gate diode model of the metal halide perovskite diode is established; the ion movement, electric field redistribution and photocurrent output are simulated; the response of the photocurrent to the external voltage is established by a simple photodiode model, and the model J is: In the model, q is the elementary charge, k B is the Boltzmann constant, T is the temperature; positive and negative ions are only distributed at the left and right ends of the region with a length of L in the perovskite, and they are allowed to jump from one end to the other; the total amount of ions is N0, and the ion-induced voltage is V N , the maximum ion induction voltage is The induced voltage generated by ion polarization offsets the external voltage; the time for ions to move from one end to the other is t = L / μE, which is the mobility of μ ions, and the electric field is considered to be uniformly distributed; the rate change of the number of positive ions on the left is expressed as Where α=μ / L 2 ;The voltage across the device is: Where V app is the applied voltage, V bi It is the built-in voltage.

2. The method for preparing an intrinsic ion gate metal halide perovskite diode according to claim 1, characterized in that: The transparent electrode layer is made of indium tin oxide (ITO) conductive glass.

3. The method for preparing an intrinsic ion gate metal halide perovskite diode according to claim 1, characterized in that: The component of the ionic liquid is methylamine acetate (MAAc) or methylamine formate (MAFa) solution.

4. The method for preparing an intrinsic ion gate metal halide perovskite diode according to claim 1, characterized in that: The perovskite layer is an organic-inorganic hybrid perovskite material methylamine lead iodide (MAPbI3).

5. The method for preparing an intrinsic ion gate metal halide perovskite diode according to claim 1, characterized in that: The intrinsic ion gate metal halide perovskite diode is used for multi-valued optoelectronic logic computing that breaks through binary logic computing.

6. The method for preparing an intrinsic ion gate metal halide perovskite diode according to claim 1, characterized in that: The intrinsic ion gate metal halide perovskite diode is used for brain-like computing and neuromorphic computing.

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