CN104291321B

CN104291321B - A kind of preparation method of graphene quantum dot film

Info

Publication number: CN104291321B
Application number: CN201410362988.6A
Authority: CN
Inventors: 王丽娟; 邹凤君; 都昊; 李一平
Original assignee: Changchun University of Technology
Current assignee: Changchun University of Technology
Priority date: 2014-07-28
Filing date: 2014-07-28
Publication date: 2016-05-11
Anticipated expiration: 2034-07-28
Also published as: CN104291321A

Abstract

The preparation method who the invention discloses a kind of graphene quantum dot (GQDs) film, concrete steps are as follows: with improved Hummers legal system for graphite oxide; Graphite oxide is dispersed in dispersant, uses the hot legal system of microwave-assistant sol agent for graphene quantum dot; Graphene quantum dot solution is dropped on substrate, and spin coating makes graphene quantum dot film. Raw material of the present invention is cheap, and equipment is simple, easy to operate; And the graphene quantum dot dissolubility of gained is good, size uniform, graphene quantum dot film thickness homogeneous, conducts electricity very well, and aspect solar cell application, prospect is considerable.

Description

A kind of preparation method of graphene quantum dot film

Technical field

The invention belongs to field of nanometer material technology, be specifically related to a kind of spin coating production method of graphene quantum dot film.

Background technology

Graphene is the hexagon lattice-like two dimensional surface film being formed with sp2 hybridized orbit by carbon atom, because of its special lattice structure, make the electronics of Graphene and the mobility in hole all be infinitely close to infinity, therefore Graphene has good electric conductivity, mechanical property and hot property, so have higher potential value in the field such as the energy, information. But Graphene is the semi-conducting material of zero with gap, is restricted in the application of optoelectronic areas. How to open being with of Graphene? mainly contain two kinds of technology, the one, chemistry mixes; The 2nd, introduce quantum confined effect.

Graphene quantum dot is the grapheme material of zero dimension, its size is below 100nm, have abundant edge effect and quantum confined effect, can come adjusting edge edge effect and quantum confined effect by controlling dimension size, regulate the physical characteristic of graphene quantum dot.

At present, be roughly divided into two classes about the method for preparing graphene quantum dot: method and from bottom to top method from top to bottom. The former comprises hydro-thermal method, solvent-thermal method, electrochemical oxidation process etc., is mainly Graphene cutting is smashed and made; The latter mainly contains ultrasonic method, solution chemical method etc., is mainly to use little molecule to prepare graphene quantum dot as precursor. The hot legal system of using microwave assisted aqueous extraction of the present invention is that for the advantage of GQDs generated time greatly reduces compared with traditional hydro-thermal method, the corresponding raising of productive rate. Even but be short of about the preparation method of graphene quantum dot film.

Summary of the invention

The object of the invention is using graphite powder as raw material, first prepare graphite oxide, then use the hot legal system of microwave-assistant sol agent for graphene quantum dot, then through steps such as solution preparation, spin coating, oven dry, to prepare graphene quantum dot film. Graphite oxide of the present invention and graphene quantum dot film have wide practical use at aspects such as photoelectric device, super capacitor and solar cells.

Technical scheme provided by the invention comprises the following steps: 1. the preparation of graphite oxide; 2. the preparation of graphene quantum dot; 3. the preparation of graphene quantum dot film.

1. the preparation of graphite oxide: get 2g graphite powder and 2g lithium nitrate in beaker, under condition of ice bath, add the concentrated sulfuric acid of 100mL98%, slowly add the potassium permanganate of 12g, stirring reaction a period of time under different temperatures, solution becomes brown, add 400mL distilled water diluting, slowly add appropriate 30% hydrogen peroxide, obtain bright yellow solution (GO), filter while hot filter cake NaOH solution washing, pH is adjusted to 7-8, be adjusted to neutrality with rare HCl, centrifugal being precipitated obtains graphite oxide with 40-50 DEG C of dry 48h in baking oven.

2. the preparation of graphene quantum dot: 0.5-5g graphite oxide is joined in the dispersant of 5-15mL, move in the microwave hydrothermal reaction kettle that liner is polytetrafluoroethylene (PTFE) (50mL), sealing is placed in microwave assisted hydrothermal synthesis apparatus, microwave power is 400W, reacts 90min at 220 DEG C, treats that temperature is down to room temperature, take out reactor, filtering gained filtrate is the dispersion liquid of graphene quantum dot in dispersant, and rotary evaporation is removed dispersant, after being dried, obtains powdery graphite alkene quantum dot.

3. the preparation of graphene quantum dot film: graphene quantum dot is dissolved in distilled water, is mixed with the solution of 0.5%-3%, solution is added drop-wise on substrate, rotate painting 10-30s with 1000-3000 and obtain GQDs film on sol evenning machine.

The GQDs film obtaining is carried out to SEM, transmission electron microscope, AFM, Fourier transform infrared spectroscopy, cyclic voltammetry scan, electrochemical impedance sign.

The dissolubility of the prepared graphene quantum dot of the present invention in solvent obviously promotes, GQDs even size distribution, the even thickness of GQDs film, electric conductivity is good, can have wide practical use as fields such as the solar cell such as cadmium telluride, dye sensitization, ultracapacitor, transparency electrodes at photoelectric device.

Brief description of the drawings

Fig. 1 is graphene quantum dot structural representation.

Detailed description of the invention

Below in conjunction with embodiment, the present invention is further elaborated, but is not to limit the invention.

Get 2g graphite powder and 2g lithium nitrate in beaker, under condition of ice bath, add the concentrated sulfuric acid of 100mL98%, slowly add the potassium permanganate of 12g, stirring reaction a period of time under different temperatures, solution becomes brown, adds 400mL distilled water diluting, slowly add appropriate 30% hydrogen peroxide, obtain bright yellow solution (GO), filter while hot filter cake NaOH solution washing, pH is adjusted to 7-8, be adjusted to neutrality with rare HCl, centrifugal being precipitated obtains graphite oxide with 45 DEG C of dry 48h in baking oven.

0.5g graphite oxide is joined in the DMSO of 5mL, move in the microwave hydrothermal reaction kettle that liner is polytetrafluoroethylene (PTFE) (50mL), sealing is placed in microwave assisted hydrothermal synthesis apparatus, microwave power is 400W, reacts 90min at 220 DEG C, treats that temperature is down to room temperature, take out reactor, filtering gained filtrate is the dispersion liquid of graphene quantum dot in DMSO, and rotary evaporation is removed DMSO, after being dried, obtains powdery graphite alkene quantum dot.

Graphene quantum dot is dissolved in distilled water, be mixed with 0.5% solution, solution is added drop-wise on substrate, on sol evenning machine, rotate painting 15s with 1000 and obtain GQDs film, the film tentatively obtaining is placed in to 180 DEG C of air dry ovens and solidifies oven dry, obtain GQDs film.

Claims

1. a preparation method for graphene quantum dot film, is characterized in that, comprises the steps:

A) graphite oxide is joined in a certain amount of dispersant, move in the microwave hydrothermal reaction kettle that liner is polytetrafluoroethylene (PTFE), sealing is placed in microwave assisted hydrothermal synthesis apparatus, microwave power is 400W, reacts 90min at 200-240 DEG C, treats that temperature is down to room temperature, take out reactor, filtering gained filtrate is the dispersion liquid of graphene quantum dot in dispersant, and rotary evaporation is removed dispersant, after being dried, obtains powdery graphite alkene quantum dot;

B) graphene quantum dot is dissolved in distilled water, be mixed with solution, solution is added drop-wise to steam and has a substrate film PEDOT:PSS(2) substrate (3) on, on sol evenning machine, spin coating tentatively obtains GQDs film, the good film of spin coating is placed in to air dry oven baking and curing, obtains last GQDs film (1).

2. the preparation method of a kind of graphene quantum dot film according to claim 1, is characterized in that dispersant is one or more in dimethyl sulfoxide (DMSO) (DMSO), DMF (DMF), ethylene glycol or glycerine.

3. the preparation method of a kind of graphene quantum dot film according to claim 1, the concentration that it is characterized in that graphene quantum dot solution is 0.5%-3%.

4. the preparation method of a kind of graphene quantum dot film according to claim 1, is characterized in that spin coating speed is 1000-3000r/min, and the spin coating time is 10s-30s.

5. the preparation method of a kind of graphene quantum dot film according to claim 1, is characterized in that substrate is Si substrate, ITO substrate or glass substrate.

6. the preparation method of a kind of graphene quantum dot film according to claim 1, is characterized in that graphite oxide is standby with improved Hummers legal system; Concrete steps are: get 2g graphite powder and 2g lithium nitrate in beaker, under condition of ice bath, add the concentrated sulfuric acid of 100mL98%, slowly add the potassium permanganate of 12g, stirring reaction a period of time under different temperatures, solution becomes brown, add 400mL distilled water diluting, slowly add appropriate 30% hydrogen peroxide, obtain bright yellow solution (GO), filter while hot filter cake NaOH solution washing, pH is adjusted to 7-8, be adjusted to neutrality with rare HCl, centrifugal being precipitated obtains graphite oxide with 40-50 DEG C of dry 48h in baking oven.