CN102965105B

CN102965105B - Graphene-CuInS2 quantum dot compound and preparation method thereof

Info

Publication number: CN102965105B
Application number: CN201210472353.2A
Authority: CN
Inventors: 高锋; 王命泰; 岳文瑾
Original assignee: Institute of Plasma Physics of CAS
Current assignee: Institute of Plasma Physics of CAS
Priority date: 2012-11-21
Filing date: 2012-11-21
Publication date: 2014-12-03
Anticipated expiration: 2032-11-21
Also published as: CN102965105A

Abstract

The invention discloses a graphene-CuInS2 quantum dot compound and a preparation method of the compound, wherein environment-friendly ethanol is taken as solvent, and the compound formed by reduced-state graphene oxide and chalcopyrite CuInS2 quantum dots is synthesized by solvothermal reaction, wherein the CuInS2 quantum dots have the size of 2-5nm; and the CuInS2 quantum dots exist in two forms including being dispersed on a graphene sheet layer in a single layer and being gathered on the surface of the graphene sheet layer to form a three-dimensional aggregation. The graphene-CuInS2 quantum dot compound has good dispersing performance in organic solvent, the preparation method is simple and environment-friendly, and massive preparation can be easily realized, so that the compound and the method have important application value in the fields such as photoelectric material, photovoltaic material and organic-inorganic complex materials.

Description

A kind of Graphene-CuInS 2quantum dot mixture and preparation method thereof

Technical field

The present invention relates to field of nanometer material technology, is exactly a kind of Graphene-CuInS ₂quantum dot mixture and preparation method thereof.

Background technology

Graphene is a kind of Two-dimensional Carbon material, and it has unique character, for example high heat conductance (~ 5000 Wm ^-1k ^-1), high carrier mobility (~ 200000 cm ²v ^-1s ^-1), high-specific surface area (~ 2630 m ²g ^-1), high stability and good optical transmittance etc., in fields such as catalysis, sensing, storage, biological medicine and photovoltaics, have important application prospect (Prog. Mater. Sci. 2011,56,1178-1271).In recent years, the mixture being formed by Graphene and inorganic nano structure has caused people's concern, in fields such as energy transformation, energy storage and catalysis, shows potential application prospect.For example, (the Angew. Chem. Int. Ed. 2010 such as Guo, 49,3014-3017) on conductive glass, by alternating deposit graphene oxide and CdSe quantum dot nano film, form superlattice film, as the complex light electrode of quantum dot sensitized solar cell (QDSSC); (Nanotechnology 2011 for Wang etc., 22,405401) take reduction-state graphene oxide sheet as lining base carries out etching with hydrothermal method growing ZnO nanorod and to nanometer rod, synthesized Graphene-ZnO nano pipe array mixture, the optoelectronic pole using it as polymer-based carbon solar cell; (Nanoscale 2012,4,441-443) by the method for adsorbing quantum dot on functionalization graphene oxide lamella, synthesized graphene oxide-CdSe quantum dot mixture, as the wide range response light electrode of QDSSC battery for Chen etc.; (J. Power Sources 2012,217,85-91) has synthesized graphene oxide-Fe by hydrothermal method to Sathish etc. ₃o ₄nano particle magnetic composite, it can be used as high performance lithium ion battery anode material; (J. Power Sources 2012,217,184-192) has synthesized reduction-state graphene oxide-Mn with microwave-assisted hydrothermal synthesis method to Liu etc. ₃o ₄nano-complex, obtains a kind of good super capacitor material; Chen etc. (ACS Nano, 2010,4,6425-6432) use in-situ hydrolysis TiCl ₄method prepared the graphene oxide-TiO with visible light catalytic performance ₂nano-complex.

CuInS ₂have narrower band gap (1.5 eV) (Chem. Mater. 2003,15,3142-3147) and larger uptake factor large (α 10 ⁵cm ^-1) (Cryst. Growth Des. 2007,7,1547-1552), be a kind of desirable solar cell material (J. Mater. Chem. 2006,16,1597-1602, Nano Lett. 2006,6,1218-1223).In the present invention, we,, with graphene oxide lamella growth in situ quantum dot and in conjunction with follow-up reduction process, obtain a kind of Graphene and CuInS ₂the mixture that quantum dot forms.

Summary of the invention

The object of this invention is to provide a kind of Graphene-CuInS ₂quantum dot mixture and preparation method thereof.

The present invention is achieved by the following technical solutions:

A kind of Graphene-CuInS ₂quantum dot mixture: described Graphene-CuInS ₂quantum dot mixture is synthetic in autoclave by solvent-thermal method, by reduction-state graphene oxide and chalcopyrite CuInS ₂quantum dot forms, CuInS ₂quantum point grain diameter is 2-5 nm, CuInS ₂quantum dot with Monolayer Dispersion on graphene sheet layer and form two kinds of forms of three-dimensional aggregate at graphene sheet layer surface aggregation and exist, CuInS ₂in quantum dot, the atomic ratio of Cu:In:S is 1:1.3:1.8.

A kind of Graphene-CuInS ₂the preparation method of quantum dot mixture: first graphene oxide is scattered in ethanol, then by Cu (Ac) ₂h ₂o, In (Ac) ₃, octadecylamine and thiocarbamide join in the alcohol dispersion liquid of graphene oxide successively, in autoclave, at 150-170 ℃, reacts 4-8 hour, then at 75-85 ℃ by hydrazine hydrate reduction, through centrifugation, washing and the dry Graphene-CuInS that obtains ₂quantum dot mixture; Described graphene oxide and Cu (Ac) ₂h ₂the mass ratio of O is 1:1-4, Cu (Ac) ₂h ₂o, In (Ac) ₃, octadecylamine tensio-active agent and thiocarbamide mol ratio be 1:1:12:4.

Advantage of the present invention is: utilize the method for solvent thermal process growth in situ quantum dot to prepare Graphene-CuInS ₂quantum dot mixture, CuInS ₂quantum point grain diameter homogeneous; Preparing solvent for use is ethanolic soln, and environmental friendliness is pollution-free; The inventive method equipment used simple (being mainly autoclave and whizzer), easy and simple to handle, the magnanimity that easily realizes mixture is synthetic; The mixture obtaining has good dispersing property in organic solvent, will have important using value in fields such as photoelectric material, photovoltaic material, composite organic-inorganic materials.

Accompanying drawing explanation

Fig. 1 is the characterization result of graphene oxide of the present invention (GO) and reduction-state graphene oxide (rGO); Wherein, (a) optical photograph of the TEM photo of GO, (b) aqueous dispersion (left side yellow is GO, and the right black is rGO), (c) XRD, (d) Raman spectrum.

Fig. 2 is Graphene-CuInS of the present invention ₂the XRD of quantum dot mixture and Raman Characterization; Wherein, (a) XRD, (b) Raman spectrum.

Fig. 3 is Graphene-CuInS of the present invention ₂the TEM(a of quantum dot mixture) and HRTEM(b, c) characterize; Wherein (b) and (c) correspond respectively to interval in (a) 2 and interval 1.

Fig. 4 is Graphene-CuInS of the present invention ₂the XPS of quantum dot mixture characterizes; Wherein, (a) full spectrum, (b) Cu2p spectrum, (c) In3d spectrum, (d) S2p compose.

Fig. 5 is Graphene-CuInS of the present invention ₂the dispersiveness (standing 6 hour after take a picture) of quantum dot mixture in different organic solvents.

Embodiment

Embodiment 1: the preparation of graphene oxide and reduction-state graphene oxide.

By 0.5 gram of graphite and 0.5 gram of NaNO ₃join in the beaker of 250 milliliters, and beaker is placed in to the frozen water of 0 ℃ mixes and bathe, then add wherein the vitriol oil (95-98%) of 23 milliliters, fully stir 15 minutes, obtain the suspension of black; In this suspension, add 4 grams of KMnO ₄, then at 35 ℃, stir and react 2 hours, obtain green suspension, then add 40 ml deionized water, at 90 ℃, stir and react 1 hour, obtain brown color suspension; Finally, in brown color suspension, add 5 milliliters of H ₂o ₂; Question response liquid is cooled to after room temperature, carries out centrifugation (12000 rpm, 10 minutes) and deionized water wash, and product vacuum-drying 24 hours at 60 ℃, obtains graphene oxide (GO).

5 milligrams of graphene oxides are scattered in 60 ml deionized water, obtain yellow suspension, be warming up to 80 ^oafter C, add 5 mL hydrazine hydrates standing 2 hours, obtain black suspension, carry out centrifugation (9000 rpm, 10 minutes) and deionized water wash, product vacuum-drying 24 hours at 60 ℃, obtains reduction-state graphene oxide (rGO).

Sign before and after graphene oxide reduction is shown in accompanying drawing 1.Transmission electron microscope (TEM) has shown the laminated structure of graphene oxide; Optical photograph has shown to be yellow after graphene oxide disperses in water, but after reduction, its aqueous dispersions is black; X-ray diffraction (XRD) has shown the generation of graphene oxide, and has different diffraction peaks before and after reduction; Raman spectrum has shown the generation of graphene oxide, and has different D(1343 cm before and after reduction ^-1) and G(1590 cm ^-1) p-ratio.

Embodiment 2: Graphene-CuInS ₂the preparation of quantum dot mixture

(2-1) preparation of graphene oxide: see embodiment 1.

(2-2) Graphene-CuInS ₂the preparation of quantum dot mixture:

In 50 milliliters of dehydrated alcohols, add 5 milligrams of graphene oxides, ultrasonic dispersion 30 minutes, obtains brown color dispersion liquid, then adds 10 milligrams of Cu (Ac) ₂h ₂o, ultrasonic dispersion 5 min, dispersion liquid becomes brown-green; In brown-green solution, add 14.6 milligrams of In (Ac) ₃and ultrasonic dispersion 10 minutes, adding 161.7 milligrams of octadecylamines ultrasonic dispersion 20 minutes, it is blue that dispersion liquid becomes palm fibre, then add 15.2 milligrams of thiocarbamides, and dispersion liquid becomes brownish black immediately, stirs 20 minutes.Black dispersion liquid is transferred to 80 milliliters containing in teflon-lined autoclave, in 160 ^ounder C condition, react 6 hours; Question response still naturally cools to after room temperature, and reaction solution is proceeded to beaker, is heated to 80 in water-bath ^oc, adds 5 mL hydrazine hydrates standing 2 hours with further redox graphene; Be cooled to after room temperature, carry out centrifugation (9000 rpm, 10 minutes) and washing with alcohol, product vacuum-drying 24 hours at 60 ℃, obtains Graphene-CuInS ₂quantum dot mixture.

(2-3) sign of product:

Mixture characterizes sees accompanying drawing 2-5.Powder X-ray RD test, has shown that product is by reduction-state graphene oxide and chalcopyrite CuInS ₂(JCPDS #85-1575) forms; Raman spectrum has shown that in mixture, D and the G p-ratio of Graphene reduces greatly, and CuInS has been described ₂graphene sheet layer surface imperfection is had to good repair; TEM and high resolution TEM(HRTEM) show CuInS ₂quantum dot size is 2-5 nm, CuInS ₂quantum dot with Monolayer Dispersion on graphene sheet layer and form two kinds of forms of three-dimensional aggregate at graphene sheet layer surface aggregation and exist; Photoelectron spectrum (XPS) analysis shows, CuInS ₂in quantum dot, the atomic ratio of Cu:In:S is 1:1.3:1.8; Optical photograph shows, Graphene-CuInS ₂quantum dot mixture has good dispersion stabilization in organic solvent (as ethanol, chloroform and chlorobenzene).

Claims

1. a Graphene-CuInS ₂quantum dot mixture, is characterized in that: described Graphene-CuInS ₂quantum dot mixture is synthetic in autoclave by solvent-thermal method, by reduction-state graphene oxide and chalcopyrite CuInS ₂quantum dot forms, CuInS ₂quantum point grain diameter is 2-5 nm, CuInS ₂quantum dot with Monolayer Dispersion on graphene sheet layer and form two kinds of forms of three-dimensional aggregate at graphene sheet layer surface aggregation and exist, CuInS ₂in quantum dot, the atomic ratio of Cu:In:S is 1:1.3:1.8;

Described Graphene-CuInS ₂the preparation method of quantum dot mixture is: first graphene oxide is scattered in ethanol, then by Cu (Ac) ₂h ₂o, In (Ac) ₃, octadecylamine and thiocarbamide join in the alcohol dispersion liquid of graphene oxide successively, in autoclave, at 150-170 ℃, reacts 4-8 hour, then at 75-85 ℃ by hydrazine hydrate reduction, through centrifugation, washing and the dry Graphene-CuInS that obtains ₂quantum dot mixture; Described graphene oxide and Cu (Ac) ₂h ₂the mass ratio of O is 1:1-4, Cu (Ac) ₂h ₂o, In (Ac) ₃, octadecylamine tensio-active agent and thiocarbamide mol ratio be 1:1:12:4.