CN110429148B

CN110429148B - Selenide nanorod, preparation method thereof and photoelectric detector prepared from selenide nanorod

Info

Publication number: CN110429148B
Application number: CN201910702294.5A
Authority: CN
Inventors: 蒋连福; 董文英
Original assignee: Nanjing Beige Electronic Technology Co ltd
Current assignee: Nanjing Beige Electronic Technology Co ltd
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2020-04-07
Anticipated expiration: 2039-07-31
Also published as: CN110429148A; CN111244206A

Abstract

The invention discloses a selenide nanorod, a preparation method thereof and a photoelectric detector prepared by the selenide nanorod, and belongs to the field of preparation of nano semiconductors. The method comprises the following steps: KOH and SeO₂Powder, AgNO₃And In (NO)₃)₃Dissolving the mixture in a non-coordinating solvent and a small amount of ethylenediamine, stirring vigorously at 200-240 ℃ under the protection of inert gas, and keeping the temperature for 12-24 hours to prepare the selenide nano-rods. Separation of hydroxide ions of alkali in molten state into

And

then, under the dilution of a non-coordinating solvent, the viscosity is reduced to improve the fluidity, In is In the alkaline environment of molten alkali₂Se₃Forming crystal nucleus with wurtzite structure, and finally inducing growth direction to promote In by competitive adsorption of ethylenediamine molecule to crystal face In reaction mixture₂Se₃Continuous adsorption of crystal nucleus

And a small amount of

And anisotropic growth. The problem of in the actual use, intrinsic conductivity is too low, leads to the spectral responsivity of detector and external quantum efficiency lower is solved.

Description

Selenide nanorod, preparation method thereof and photoelectric detector prepared from selenide nanorod

Technical Field

The invention belongs to the field of preparation of nano semiconductors, and particularly relates to a selenide nanorod, a preparation method thereof and a photoelectric detector prepared by the selenide nanorod.

Background

As the basis of nano-science and technology, the preparation and application of new nano-materials have become an important research direction in nano-science and technology. Semiconductor nano materials are gradually becoming hot research materials of the present society due to the specific physicochemical properties of the semiconductor nano materials. Researchers successfully develop a series of devices with representative functions, such as a light-emitting diode, a large solar cell, a photoelectric detector and the like, by applying the nano semiconductor to a photoelectric device, and play an indispensable role in actual industrial production and social life. Taking a photodetector as an example, the photoconductive characteristic of a semiconductor material is a key index for determining the performance of the photodetector. Therefore, how to realize the controllable preparation of the nano material and give full play to the application value of the nano material in the photoelectric field is also an important problem to be considered by researchers.

Among many nano semiconductor materials, a metal sulfide semiconductor is a research focus of the present, materials such as ZnO, ZnS, CdS, etc. have been widely used in the field of photoelectricity, and research on selenides is relatively delayed. Wherein, indium selenide In₂Se₃As a new type of nano-material, due to its unique crystal structure, a plurality of one-dimensional nanobelts are generally stacked in one direction by van der waals force to form a one-dimensional nanorod. The nano indium selenide material can be used as a single device and can also be used as a connecting unit in a nano device, so that the research on the nano indium selenide material is of great significance. However, in practical use, the intrinsic conductivity is too low, which results in low thermoelectric power factor, and thus the spectral responsivity and external quantum efficiency of the detector prepared thereby are low.

Disclosure of Invention

The purpose of the invention is as follows: a method for manufacturing a nanorod film photodetector is provided to solve the problems involved in the background art.

The technical scheme is as follows: a nanorod thin film photodetector, comprising:

substrate of SiO₂A rectangular base plate prepared from Si;

the electrode, carve two interdigital Au electrodes that deflect the predetermined distance on the said base, its length-width ratio is 10:1, the finger interval is the same as said interdigital Au electrode width;

the semiconductor medium is filled with selenide nano-rods between the electrodes to form a film;

the selenide nanorods are

，x=0～0.05。

The preparation method of the selenide nanorod comprises the following steps:

s1, mixing KOH and SeO₂Powder, AgNO₃And In (NO)₃)₃Placing into a reaction vessel, and adopting mechanical shaking/stirring to fully mix reactants;

s2, adding an organic solvent and a small amount of ethylenediamine into the reaction container, heating to 80-100 ℃ under the protection of inert gas, and stirring by ultrasonic waves until the solid is completely dissolved;

s3, continuously heating to 200-240 ℃ under the protection of inert gas, violently stirring, and keeping the temperature for 12-24 hours;

and S4, after the nano-rod is cooled to room temperature, collecting, centrifuging, washing and drying the nano-rod product.

In further implementation, KOH and SeO in the step S1₂Powder, AgNO₃And In (NO)₃)₃The molar ratio of the components is 100-1000: 5: 3 x: feeding at 5-3x, wherein x = 0-0.05.

In a further embodiment, the reaction vessel is made of polytetrafluoroethylene or coated with a polytetrafluoroethylene coating on the inside thereof.

In a further embodiment, the organic solvent is a non-coordinating solvent, and is at least one of a medium-long chain monounsaturated fatty acid, a medium-long chain alkylamine, a medium-long chain monounsaturated olefin, or a medium-long chain cycloalkane.

In the further implementation process, the adding amount of the ethylenediamine is 1-5% of the volume of the added organic solvent.

In a further embodiment, the inert gas is at least one of nitrogen, argon, neon.

In a further implementation process, the step S4 specifically includes:

s41, dissolving the product with deionized water, cleaning, adjusting with dilute hydrochloric acid to remove potassium hydroxide on the surface of the product, and then continuously cleaning with deionized water;

s42, adding the cleaned product into an acetone cleaning agent, fully stirring by using ultrasonic waves, and then centrifuging;

s43, taking out the centrifuged lower-layer solid product, adding the centrifuged lower-layer solid product into an isopropanol cleaning agent, fully stirring the mixture by using ultrasonic waves, and centrifuging the mixture;

s44, taking out the centrifuged lower-layer solid product, and repeating the steps S42-S42 for 2-3 times;

s45, and drying the final centrifugal product in a vacuum drying oven at 50-80 ℃ to obtain the nanorod.

Semiconductor medium used in nano-rod film photoelectric detector

The nano-rod is the product obtained by the preparation method.

Has the advantages that: the invention relates to a method for preparing a nano-rod film photoelectric detector, which separates hydroxide ions of alkali in a molten state into

And

then, under the dilution of an organic solvent, reducing the viscosity as much as possible to improve the fluidity thereof, providing a reaction environment In which In is In such an alkaline environment of a molten alkali₂Se₃Forming crystal nucleus with wurtzite structure, and finally inducing growth direction to promote In by competitive adsorption of ethylenediamine molecule to crystal face In reaction mixture₂Se₃Continuous adsorption of crystal nucleus

And a small amount of

Drawings

Fig. 1 is a schematic view of the structure of a photodetector according to the present invention.

FIG. 2 is a Scanning Electron Microscope (SEM) image of the product prepared in example 1 of the present invention.

FIG. 3 is a Scanning Electron Microscope (SEM) image of the product prepared in example 2 of the present invention.

The reference signs are: a substrate 1, an electrode 2 and a semiconductor medium 3.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

As shown in fig. 1, a nanorod film photodetector includes: a substrate 1, an electrode 2 and a semiconductor medium 3. Wherein, the substrate 1 is made of SiO₂A rectangular base plate prepared from Si; the electrodes 2 are two interdigital Au electrodes which are carved on the substrate 1 and are offset by a preset distance, the length-width ratio of the electrodes is 10:1, and the finger spacing is the same as the width of the interdigital Au electrodes; the semiconductor medium 3 is a selenide nano-rod filled between the electrodes 2 to form a film.

Among many nano semiconductor materials, a metal sulfide semiconductor is a research focus of the present, materials such as ZnO, ZnS, CdS, etc. have been widely used in the field of photoelectricity, and research on selenides is relatively delayed. Wherein, In₂Se₃Indium selenide, as a novel nano material, is generally stacked by van der waals force along one direction from a plurality of one-dimensional nanobelts due to its unique crystal structure to form a one-dimensional nanorod. It can be made intoThe nano indium selenide material can be used as a single device and can also be used as a connecting unit in a nano device, so that the research on the nano indium selenide material is of great significance. However, in practical use, the intrinsic conductivity is too low, which results in low thermoelectric power factor, and thus the spectral responsivity and external quantum efficiency of the detector are low. Thus, the selenide nanorods are

，x=0～0.05。

Multiple comparison experiments prove that the invention adopts a novel nano material synthesis method-composite alkali medium method to prepare

And meanwhile, partial method is improved. Like pure water will ionize to form H⁺And OH^-Similarly, the hydroxide ion of alkali in molten state can be further separated into

And

at this time, the viscosity of the molten alkali solution is large, and the fluidity is poor, which is not favorable for the formation and growth of crystal nuclei. In the prior art, a small amount of deionized water is usually added, so that not only can the alkalinity of the molten alkali be improved, but also the viscosity of the molten alkali can be reduced and the fluidity can be improved. However, it is considered that the deionized water is a coordination solvent and has certain influence on the growth orientation during the crystal nucleus growth process, so that the method is suitable for the synthesis of most of nano materials which do not have excessive requirements on the growth orientation. Due to the invention

The material is mainly applied to a photoelectric detector, and the crystal growth orientation, the integrity of a one-dimensional structure and the photosensitive performance of the material have great influence. Therefore, there is a need for improvements to the above-described methods to improve

The integrity of the one-dimensional structure of the nanomaterial, in the invention, the coordinating solvent is replaced by a non-coordinating solvent, so that the adhesion of molten alkali is reduced and the fluidity is improved. Although the alkalinity of molten alkali cannot be improved like deionized water, the synthesis yield and the synthesis rate of the nano material are reduced, but the integrity of the crystal structure can be ensured. Finally, a small amount of ethylenediamine is added, and the growth direction is induced by competitive adsorption of ethylenediamine molecules on crystal faces In the reaction mixture to promote In₂Se₃Continuous adsorption of crystal nucleus

And a small amount of

And anisotropic growth, improving the integrity of the one-dimensional structure of the crystal.

Further will be

The nano material is used as a semiconductor medium to be prepared into a nanorod film photoelectric detector for application, and the photoconductive characteristic of the nano material is tested (the conductivity of the material changes under illumination).

The invention will now be further described with reference to the following examples, which are intended to be illustrative of the invention and are not to be construed as limiting the invention. The examples, where specific techniques and reaction conditions are not indicated, can be carried out according to the techniques or conditions or product specifications described in the literature in the field. Reagents, instruments or equipment of any manufacturer not indicated are commercially available.

Example 1

Preparing a selenide nanorod: 20g of KOH, 5mmol of SeO₂Powder, 0.1mmol of AgNO₃And 4.9mmol of dried In (NO)₃)₃▪4H₂Adding O into a stainless steel reaction kettle lined with polytetrafluoroethylene, adopting mechanical stirring, fully mixing and reactingAdding 10ml of 1-octadecene and 0.2ml of ethylenediamine into a reaction container, heating to 80-100 ℃ under the protection of argon, and stirring by adopting ultrasonic waves until all solids are dissolved; then, under the protection of argon, continuously heating to 200-240 ℃, violently stirring by adopting a magnetic stirrer, and keeping the temperature for 12 hours; and after the mixture is cooled to room temperature, collecting the nanorod product.

Removing impurities of the selenide nanorods: dissolving the product with deionized water, cleaning, adjusting with dilute hydrochloric acid to remove potassium hydroxide on the surface of the product, and continuously cleaning with deionized water; then adding the cleaned product into an acetone cleaning agent, fully stirring by using ultrasonic waves, and then centrifuging; taking out the centrifuged lower-layer solid product, adding the centrifuged lower-layer solid product into an isopropanol cleaning agent, fully stirring the mixture by using ultrasonic waves, and centrifuging the mixture; taking out the centrifuged lower solid product, and repeating the above steps for 2 times; and drying the final centrifugal product in a vacuum drying oven at 60 ℃ to obtain the nanorod.

Preparing a photoelectric detector: photoetching interdigital Au electrodes with the width of 25um, the length of 250um and the finger spacing of 25um on a silicon substrate with the length multiplied by the width multiplied by the height of 300 multiplied by 20 um; then ultrasonically dispersing the synthesized nano rod in chloroform according to the concentration of 5mol/L, then dripping the nano rod on an interdigital Au electrode, and drying the interdigital Au electrode in a vacuum oven at the temperature of 40 ℃ for half an hour to obtain the nano rod film semiconductor.

Detection of photoconductive characteristics at a fixed light intensity of 12.05mWcm^-2Under the bias of 20V, the time response of the thin-film photoelectric detector is 0.9s and the current on the nano-film is reduced from 280nA to 3nA in the processes of illumination from 'on' (illumination condition) and 'off' (dark field condition); during the illumination from "off" (dark field condition) and "on" (illumination condition), the time response of the thin film photodetector is 0.5s and the current on the nano-film is reduced from 3nA to 280 nA.

Example 2

Preparing a selenide nanorod: putting 20g of KOH, 5mmol of SeO2 powder, 0.1mmol of AgNO3 and 4.9mmol of dried In (NO3)3 into a stainless steel reaction kettle lined with polytetrafluoroethylene, fully mixing reactants by mechanical stirring, adding 5ml of deionized water and 0.1ml of ethylenediamine into the reaction kettle, heating to 80-100 ℃ under the protection of argon, and stirring by ultrasonic waves until all solids are dissolved; then, under the protection of argon, continuously heating to 200-240 ℃, violently stirring by adopting a magnetic stirrer, and keeping the temperature for 12 hours; and after the mixture is cooled to room temperature, collecting the nanorod product.

Detection of photoconductive characteristics at a fixed light intensity of 12.05mWcm^-2Under the bias of 20V, the time response of the thin-film photoelectric detector is 1.7s in the process of illumination from 'on' (illumination condition) and 'off' (dark field condition), and the current on the nano-film is reduced from 260nA to 3 nA; during the illumination from "off" (dark field condition) and "on" (illumination condition), the time response of the thin film photodetector is 0.9s and the current on the nano-film is reduced from 3nA to 260 nA.

Example 3

Preparing a selenide nanorod: 20g of KOH, 5mmol of SeO₂Powder and 5mmol of dried In (NO)₃)₃▪4H₂Putting O into a stainless steel reaction kettle lined with polytetrafluoroethylene,fully mixing reactants by adopting mechanical stirring, then adding 10ml of 1-octadecene and 0.2ml of ethylenediamine into a reaction container, heating to 80-100 ℃ under the protection of argon, and stirring by adopting ultrasonic waves until all solids are dissolved; then, under the protection of argon, continuously heating to 200-240 ℃, violently stirring by adopting a magnetic stirrer, and keeping the temperature for 12 hours; and after the mixture is cooled to room temperature, collecting the nanorod product.

Detection of photoconductive characteristics at a fixed light intensity of 12.05mWcm^-2Under the bias of 20V, the time response of the thin-film photoelectric detector is 1.0s and the current on the nanometer thin film is reduced from 60nA to 9nA in the processes of illumination from 'on' (illumination condition) and 'off' (dark field condition); during the illumination from "off" (dark field condition) and "on" (illumination condition), the time response of the thin film photodetector is 0.5s and the current on the nano-film is reduced from 9nA to 60 nA.

Comparative example 1

Preparing a photoelectric detector: photoetching interdigital Au electrodes with the width of 25um, the length of 250um and the finger spacing of 25um on a silicon substrate with the length multiplied by the width multiplied by the height of 300 multiplied by 20 um; then, the commercial ZnS nano-rod is ultrasonically dispersed in chloroform according to the concentration of 5mol/L, and then is dripped on an interdigital Au electrode, and is dried in a vacuum oven at the temperature of 40 ℃ for half an hour to obtain the nano-rod thin film semiconductor.

Detection of photoconductive characteristics at a fixed light intensity of 12.05mWcm^-2Under the bias of 20V, the time response of the thin-film photoelectric detector is 1.1s and the current on the nanometer thin film is reduced from 150nA to 2nA in the processes of illumination from 'on' (illumination condition) and 'off' (dark field condition); during the illumination from "off" (dark field condition) and "on" (illumination condition), the time response of the thin film photodetector is 0.6s and the current on the nano-film is reduced from 2nA to 150 nA.

Comparing examples 1-3 with comparative example 1, the response time of the nanorod semiconductor material prepared in the invention is 0.5s and 0.9s, the intrinsic conductivity change rate of the nanomaterial at the time of on-off is up to 90 times, and the nanorod semiconductor material is comparable to or even more excellent than commercially available semiconductor nanorods (the response time is 0.6s and 1.1s, and the intrinsic conductivity change rate of the nanomaterial at the time of on-off is 75 times). Wherein, comparing FIGS. 2-3, it can be seen that example 2 (using deionized water to reduce the viscosity of the molten base)

The one-dimensional integrity of the nanomaterial is not high enough, which in turn results in low photosensitive performance (response times of 0.9s and 1.7 s). Example 3 (undoped silver ion)

The intrinsic conductivity of the nanomaterial is large, resulting in a small rate of change of the intrinsic conductivity of the nanomaterial at the time of on-off.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

Claims

1. a preparation method of selenide nanorod, is characterized in that, comprises the steps:

S1, put KOH, SeO ₂ powder, AgNO ₃ and In(NO ₃ ) ₃ into the reaction vessel, and use mechanical shaking/stirring to fully mix the reactants;

S2, add organic solvent and a small amount of ethylenediamine into the reaction vessel, under the protection of inert gas, be heated to 80～100 ℃, and adopt ultrasonic stirring, until all solids dissolve;

S3, then under the protection of inert gas, continue to heat up to 200～240 ℃, and stir vigorously, and keep warm for 12～24 hours;

S4. After it is cooled to room temperature, the nanorod product is collected, centrifuged, washed and dried.

2 . The preparation method of selenide nanorods according to claim 1 , wherein in the S1 step, KOH, SeO ₂ powder, AgNO ₃ and In(NO ₃ ) ₃ are 100-1000:5 according to the molar ratio. 3 . : 3x: 5-3x for feeding, x=0～0.05.

3 . The preparation method of selenide nanorods according to claim 1 , wherein, in the step S1 , the reaction vessel is made of polytetrafluoroethylene or is coated with a polytetrafluoroethylene coating. 4 .

4. the preparation method of selenide nanorod according to claim 1, is characterized in that, in described S2 step, organic solvent is non-coordinating solvent, at least is the monounsaturated fatty acid of medium and long chain, the alkane of medium and long chain One of base amine, medium and long chain monounsaturated olefin or medium and long chain cycloalkane.

5 . The preparation method of selenide nanorods according to claim 1 , wherein the amount of ethylenediamine added in the step S2 is 1-5% of the volume of the organic solvent added. 6 .

6 . The preparation method of selenide nanorods according to claim 1 , wherein the inert gas is at least one of nitrogen, argon and neon. 7 .

7. the preparation method of selenide nanorod according to claim 1, is characterized in that, described S4 step is specifically:

S41, dissolving the product with deionized water, cleaning, and then using dilute hydrochloric acid to adjust and remove potassium hydroxide on the surface of the product and then continue to use deionized water for cleaning;

S42, then adding the cleaned product into the acetone cleaning agent, fully stirring with ultrasonic waves, and then centrifuging;

S43, take out the lower layer solid product after centrifugation, add in isopropanol cleaning agent, use ultrasonic wave to fully stir, and then centrifuge;

S44, taking out the lower layer solid product after centrifugation, and repeating the above steps S42-S42 2-3 times;

S45, the final centrifugation product is dried in a vacuum drying oven at 50-80° C. to obtain the nanorods.

8. A selenide nanorod obtained based on the preparation method according to any one of claims 1 to 7, wherein the molecular formula of the selenide nanorod is (Ag _3x In _1-x ) ₂ Se ₃ , x =0～0.05.

9. A nanorod thin film photodetector prepared based on the described selenide nanorod of claim 8, is characterized in that, comprising:

Substrate, a rectangular base plate made of SiO ₂ /Si;

electrodes, two interdigital Au electrodes offset by a predetermined distance are engraved on the substrate, the ratio of length to width is 10:1, and the finger spacing is the same as the width of the interdigital Au electrodes;

A semiconductor medium filled with selenide nanorods between the electrodes to form a thin film;

The selenide nanorod is (Ag _3x In _1-x ) ₂ Se ₃ , and x=0-0.05.