CN101863451B

CN101863451B - Method for preparing zinc oxide in three-dimensional nanostructure with cryogenic fluid method

Info

Publication number: CN101863451B
Application number: CN201010152393XA
Authority: CN
Inventors: 李珍; 方耀国; 彭丽微; 窦金霞; 胡芸芸; 吴明红
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2010-04-20
Filing date: 2010-04-20
Publication date: 2012-08-29
Anticipated expiration: 2030-04-20
Also published as: CN101863451A

Abstract

The invention relates to a method for preparing zinc oxide in a three-dimensional nanostructure with a cryogenic fluid method. The method concretely comprises the following steps of: a, carrying out hydrophilicity treatment on processed and single-side polished silicon chips; b, dissolving 0.1098g of Zn(AC)2.2H2O into 25 ml of ethanol, stirring until the Zn(AC)2.2H2O is completely dissolved, spin-coating on the polished surface of the silicon chip obtained in the step a, and drying; c, dissolving Zn(NO3)2.6H2O (0.025M) and hexamethylenetetramine (0.025M) into 250 ml of deionized water, stirring for dissolving, then adding 1.16 g of EDTA-2Na.2H2O, and stirring until the EDTA-2Na.2H2O is completely dissolved; and d, hanging and immersing the silicon chip obtained in step b with the front surface facing downwards into the solution obtained in step c, reacting for 4-6h at 80 DEG C, washing with deionized water, and drying to obtain a layer of white substance on the silicon chip, i.e. the zinc oxide in the three-dimensional nanostructure. In the invention, the zinc oxide in the three-dimensional nanostructure is prepared with the cryogenic fluid method, the whole reaction process is carried out in the open solution, thereby the high pressure condition is avoided, expensive and complex instruments and high pressure reaction kettles are unneeded, the reaction device is simple, and the process condition is environment friendly and mild.

Description

The cryogenic fluid legal system is equipped with the method for 3-D nano, structure zinc oxide

Technical field

The present invention relates to a kind of nano-ZnO preparation, particularly a kind of method that adopts the cryogenic fluid legal system to be equipped with nano zine oxide.

Background technology

Semi-conducting material is meant that resistivity is 10 ^-3～10 ^-8Ω cm, the material between metal and insulator.Semi-conducting material is an important foundation material of making transistor, integrated circuit, power electronic devices, opto-electronic device, is supporting the development of electronics and information industries such as communication, computer and network technologies.ZnO is a kind of important direct wide band gap semiconducter inorganic material; Energy gap under the room temperature is 3.37eV; Its exciton bind energy is 60meV, is higher than GaN (25meV) and ZnSe (22meV), thereby ZnO is easy under room temperature or higher temperature, realize high efficiency Laser emission.ZnO has more stable physicochemical property simultaneously, and it is with a wide range of applications in fields such as solar cell, sensor, an emission, nano generator, photodetector, light emitting diode and photocatalysis.At present, people have adopted many methods to prepare various ZnO nanostructureds, such as vapour deposition process, cryogenic fluid chemical method, cryogenic fluid chemical method, electrochemical method, template, microwave method etc.

In recent years, three-dimensional ZnO nanostructured wherein had the pertinent literature report to adopt the three-dimensional ZnO nanostructured of Hydrothermal Preparation owing to having unique pattern and characteristic to receive much concern.The three dimensional composite structure that the preparation of Z.L.Wang seminar of the georgia ,u.s.a Institute of Technology is made up of ZnO nano wire and optical fiber, this structure significantly improves the energy conversion efficiency of DSSC; The Xu Jia of Shanghai University waits the ZnO structure of people through Hydrothermal Preparation " branch " shape by force, finds that the air-sensitive performance of this structure is more excellent than one-dimensional nano line; People such as the G.Feng of Nanjing University adopt the Hydrothermal Preparation nanocages, and this structure can reduce the catalytic temperature of strong oxidizer ammonium perchlorate, makes it aspect catalyst, certain application prospect arranged.But the three-dimensional ZnO nanostructured of Hydrothermal Preparation has following shortcoming: carry out in (1) airtight container, can't observe growth course, and not directly perceived; (2) equipment requirements high (steel of high temperature high voltage resistant, corrosion resistant liner), technical difficulty big (temperature and pressure control is strict), cost height; (3) poor safety performance.

The solution chemistry method be Uppsala Univ Sweden's physical chemistry to be L.Vayssieres proposed during at preparation ZnO monodimension nanometer material in 2003 first, 90 ℃ realized ZnO on substrate growth and obtained nanometer stick array.After this, this method prepares nano-ZnO and obtains a lot of achievements.People such as the Berkeley branch school P.D.Yang of California, USA university are based on the large-area nanometer rods display of method for preparing excess of export; They change substrate again simultaneously, as: ITO, Sapphire, titanium sheet, dimethione (PDMS) substrate are also prepared the nanometer rods display.Then Yang seminar prepares on the FTO substrate through the cryogenic fluid chemical method that up rightness is good, the big ZnO nano wire of aspect ratio, has successfully developed ZnO nano wire dye-sensitized cell based on these nano wires; People such as the L.D.Zhang of solid institute of the Chinese Academy of Sciences are at Zn (NO ₃) ₂6H ₂Adding citric acid in O and the hexa solution receives; Changed the ZnO crystal direction of growth through the citrate influence of surfactant; By the original bar-shaped layered nano-structure that becomes, this structure has big specific area and methylene blue is had good photocatalytic Degradation; People such as C.Ge ' rardin adopt and under the lauryl sodium sulfate Action of Surfactant, prepare ZnO nano-sheet structure with quadrat method.Adopt the cryogenic fluid chemical method to prepare nano material and need not complex device, have simultaneously that cost is lower, easy to operate, equipment is simple, growth conditions is gentle, be fit to advantages such as production in enormous quantities.

Summary of the invention

The object of the present invention is to provide a kind of cryogenic fluid legal system to be equipped with the method for 3-D nano, structure zinc oxide.

For achieving the above object, reaction mechanism of the present invention is following:

(CH ₂) ₆N ₄+6H ₂O→6HCHO+4NH ₃；

NH ₃+H ₂O→NH ₄ ⁺+OH ^-；

2OH ^-+Zn ²⁺→Zn(OH) ₂；

2EDTA ^-+Zn ²⁺→[Zn(EDTA) ₂] _n

According to above-mentioned mechanism, the present invention adopts following technical scheme:

A kind of cryogenic fluid legal system is equipped with the method for 3-D nano, structure zinc oxide, it is characterized in that the concrete steps of this method are:

The silicon chip of the single-sided polishing that a. will handle carries out hydrophily to be handled;

B. with 0.1098g Zn (AC) ₂2H ₂O is dissolved in the 25ml ethanol, is stirred to abundant dissolving, is spin-coated on the burnishing surface of step a gained silicon chip drying then;

C. with Zn (NO ₃) ₂6H ₂O (0.025M) and hexa (0.025M) are dissolved in stirring and dissolving in the 250ml ionized water, and then add 1.16g EDTA-2Na2H ₂O is stirred to abundant dissolving;

D. the suspension of step b gained silicon chip face down is immersed in the step c gained solution, 80 ℃ were reacted 4-6 hour, with drying after the washed with de-ionized water, on silicon chip, obtained one deck whiteness at last, were the zinc oxide of 3-D nano, structure.

The concrete grammar that above-mentioned hydrophily is handled is: the silicon chip of the single-sided polishing that will handle is put into the mixed solution of being made up of by 1: 1: 5 volume ratio hydrogen peroxide solution, ammoniacal liquor and deionized water, handles 1 hour down for 85 ℃.

The silicon chip of the single-sided polishing of above-mentioned processing is: the silicon chip of single-sided polishing is put into the organic matter that ethanol and acetone soln each ultrasonic half an hour remove silicon chip surface.

Spin coating among the above-mentioned step b is to be to carry out spin coating under 1000 rev/mins at rotating speed.

The present invention prepares the ZnO 3-D nano, structure through the cryogenic fluid chemical method; Entire reaction course is in uncovered solution, to carry out; Therefore avoided condition of high voltage, need not the instrument and the autoclave of expensive, consersion unit is simple and have environmental friendliness, gentle process conditions.Again because be water as solvent, avoided the safety hazard that causes because of organic solvent evaporation.The growth course of ZnO nanometer flower structure comprises the heterogeneous nucleation on hydrolysis-condensation, dehydration and the substrate of metal ion.The experimentation of this method is under lower temperature (80 ℃), and silicon chip is immersed in given Zn ²⁺Reacting by heating in the precursor solution of concentration obtains the ZnO nano material on reacted substrate.Owing to add surfactant EDTA-2Na2H ₂O, the EDTA molecule will have (0001)-Zn generation chelation of positive charge with polar surface, and this effect will reduce (0001) surface ability, reduces the c axle speed of growth; And the relative growth rate of quickening crystal on side face.Along with the increase in reaction time, obtain " rose " shape ZnO structure of forming by nanometer sheet at last.

Description of drawings:

Fig. 1 is Zn (NO ₃) ₂6H ₂O, hexa and EDTA-2Na2H ₂O cryogenic fluid method is synthesized " rose " shape structure, field emission scanning electron microscope figure (a, b), transmission electron microscope figure (TEM) (c) and high resolution transmission electron microscopy (d), (c) illustration is SEAD figure (SAED);

Fig. 2 is X-ray diffraction (XRD) collection of illustrative plates.

The specific embodiment

Embodiment one: the preparation of 3-D nano, structure zinc oxide:

(1). the silicon chip of single-sided polishing is put into ethanol, acetone soln each ultrasonic half an hour, removes the organic matter of silicon chip surface; Put into hydrogen peroxide solution (30%), ammoniacal liquor (30%), deionized water (volume ratio 1: 1: 5) mixed solution then, did hydrophily in following 1 hour for 85 ℃ and handle;

(2). take by weighing a certain amount of 0.1098g Zn (AC) ₂2H ₂O puts into ethanol (25ml) solution, is placed on and stirs fully dissolving on the magnetic stirring apparatus.The burnishing surface (5-7 time) of zinc acetate ethanolic solution spin coating (rotating speed: 1000 rev/mins) at silicon chip, oven dry is 1 hour in 100 ℃ of air dry ovens then;

(3). with 1.8593g Zn (NO ₃) ₂6H ₂O and 0.8762g hexa are put into the 250ml deionized water, and then add 1.16g EDTA-2Na2H ₂The dissolving of O magnetic agitation;

(4). the silicon chip face down after will drying is suspended in (3) solution, and 80 ℃ of reactions 4-6 hour are dried reacted silicon chip after with the deionized water rinsing several times; On silicon chip, obtain one deck whiteness.

The gained whiteness is carried out various signs.Referring to Fig. 1 and Fig. 2.Sample under Fig. 1 (a) low power scanning electron microscopic observation; Fig. 1 (b) is the high resolution scanning Electronic Speculum figure of single flower-like structure, can know from Fig. 1 (b): " rose " shape ZnO structure is to be formed by a plurality of nanometer sheet stackings; Fig. 1 (c) is transmission electron microscope figure, and illustration is the SEAD spot of nanometer sheet, is kind of a hexagonal structure structure; Fig. 1 (d) is high resolution transmission electron microscopy figure, and interplanar distance is 0.282nm among the figure, and is consistent with (10-10) pairing interplanar distance, shows: the ZnO crystal direction of growth is to grow along [10-10] side surface direction.Fig. 2 is the X-ray diffractogram of " rose " shape ZnO; All diffraction maximums are consistent with ZnO standard card (JCPDS card no.36-1451); Mainly contain three diffraction maximums among the figure; (002) peak position obviously is better than (001) and (101) peak position, this with Fig. 1 (a) in a large amount of exposed active face ((0001) face) consistent.

Claims

1. a cryogenic fluid legal system is equipped with the method for 3-D nano, structure zinc oxide, it is characterized in that the concrete steps of this method are:

B. with the Zn (AC) of 0.02M ₂2H ₂O is dissolved in the 25ml ethanol, is stirred to abundant dissolving, is spin-coated on the burnishing surface of step a gained silicon chip drying then;

C. with the Zn (NO of 0.025M ₃) ₂6H ₂The hexa of O and 0.025M is dissolved in the dissolving of 250ml deionized water for stirring, and then adds 1.16g EDTA-2Na2H ₂O is stirred to abundant dissolving;

2. cryogenic fluid legal system according to claim 1 is equipped with the method for 3-D nano, structure zinc oxide; It is characterized in that the concrete grammar that described hydrophily is handled is: the silicon chip of the single-sided polishing that will handle is put into the mixed solution of being made up of by the volume ratio of 1:1:5 hydrogen peroxide solution, ammoniacal liquor and deionized water, handles 1 hour down for 85 ℃.

3. cryogenic fluid legal system according to claim 1 is equipped with the method for 3-D nano, structure zinc oxide, it is characterized in that the silicon chip of the single-sided polishing of described processing is: the silicon chip of single-sided polishing is put into the organic matter that ethanol and acetone soln each ultrasonic half an hour remove silicon chip surface.

4. cryogenic fluid legal system according to claim 1 is equipped with the method for 3-D nano, structure zinc oxide, it is characterized in that spin coating among the described step b is is to carry out spin coating under 1000 rev/mins at rotating speed.