阅读说明：本技术 一种贵金属/半导体诱导上转换增强的复合薄膜 (Composite film with enhanced noble metal/semiconductor induced up-conversion ) 是由 丛妍 杨扬 董斌 尚景雨 于 2019-09-20 设计创作，主要内容包括：本发明属于稀土掺杂上转换材料技术领域,公开了一种贵金属/半导体诱导上转换增强的复合薄膜。包括贵金属层Au纳米棒,半导体层W<Sub>18</Sub>O<Sub>49</Sub>纳米线以及发光层上转换发光材料稀土掺杂NaYF<Sub>4</Sub>粒子；共三层最终构成稀土掺杂NaYF<Sub>4</Sub>/Au纳米棒/W<Sub>18</Sub>O<Sub>49</Sub>纳米线复合薄膜。该贵金属/半导体诱导上转换增强的复合薄膜是一种在980nm激光二极管激发下能够表现出超强上转换发光的复合薄膜,工艺简单灵活,稳定性良好,可重复性高,可用于检测荧光染料分子。由于高效发光特性,也有潜力应用于生物检测、太阳能电池等领域。(The invention belongs to the technical field of rare earth doped up-conversion materials, and discloses a composite film with enhanced up-conversion induced by noble metal/semiconductorAnd (3) a membrane. Comprises a noble metal layer Au nanorod and a semiconductor layer W 18 O 49 Nanowire and rare earth doped NaYF (rare earth-doped yttrium fluoride) of conversion luminescent material on luminescent layer 4 Particles; three layers are formed finally to form the rare earth doped NaYF 4 Au nanorod/W 18 O 49 And (3) a nanowire composite film. The composite film with the enhanced noble metal/semiconductor-induced up-conversion is a composite film capable of showing ultra-strong up-conversion luminescence under the excitation of a 980nm laser diode, has simple and flexible process, good stability and high repeatability, and can be used for detecting fluorescent dye molecules. Due to the high-efficiency luminescence property, the method has the potential to be applied to the fields of biological detection, solar cells and the like.)

1. A composite film with enhanced noble metal/semiconductor induced up-conversion is characterized by comprising a noble metal layer Au nanorod and a semiconductor layer W₁₈O₄₉Nanowire and rare earth doped NaYF (rare earth-doped yttrium fluoride) of conversion luminescent material on luminescent layer₄Particles; three layers are formed finally to form the rare earth doped NaYF₄Au nanorod/W₁₈O₄₉A nanowire composite film; the Au nanorod is an Au nanorod with an adjustable plasma resonance position.

2. The noble metal/semiconductor-induced upconversion-enhanced composite film according to claim 1, wherein the noble metal Au nanorod with the adjustable plasmon resonance position is obtained by a method comprising the following steps: the seed solution is prepared by mixing gold source solution A with surfactant solution B, adding reducing agent solution C under vigorous stirring, and standing for 30-40 min; the growth solution is prepared by mixing a surfactant solution B and a surfactant solution D, magnetically stirring for dissolving, cooling, adding a solution E, standing for 15-20min, then adding a gold source solution A, magnetically stirring for 90-120min, introducing a certain volume of inorganic strong acid solution F, adding a strong reducing polyhydroxy solution G, and violently stirring; and finally, injecting a small amount of seed solution into the growth solution to perform seed-mediated reaction, and purifying the obtained reaction product after the reaction is finished to obtain the Au nanorod.

3. The composite film with enhanced noble metal/semiconductor-induced upconversion as claimed in claim 2, wherein the gold source solution a is tetrachloroauric acid trihydrate: 0.5-1 mM, surfactant solution B is cetyl trimethyl ammonium bromide: wherein the concentration of the surfactant solution B cetyl trimethyl ammonium bromide in the seed solution is 0.2-0.4M, the concentration of the surfactant solution B cetyl trimethyl ammonium bromide in the growth solution is 0.037-0.047M, and the reducing agent solution C is sodium borohydride: 0.01-0.02M, and the surfactant solution D is sodium oleate: 4mM, solution E silver nitrate: 4mM, and the inorganic strong acid solution F is hydrochloric acid: 2-6 mL, wherein the strong reducing polyhydroxy solution G is ascorbic acid: 0.064M;

the seed mediated reaction is carried out at 30 ℃ for 12-14 h;

the purification is to obtain the Au nanorod after the reaction product is centrifuged by ultrapure water and washed.

4. The noble metal/semiconductor-induced upconversion enhancement composite film according to claim 1, wherein the semiconductor W is a metal oxide or a metal nitride₁₈O₄₉The nanowire film is obtained by the following method: dissolving a tungsten source in a solvent, magnetically stirring, transferring into a polytetrafluoroethylene reaction kettle containing a substrate for solvothermal reaction, and reactingPurifying the product to obtain W₁₈O₄₉A thin film of nanowires.

5. The noble metal/semiconductor-induced upconversion enhancement composite film according to claim 4,

the tungsten source is tungsten hexacarbonyl: 25-30 mg of absolute ethyl alcohol, wherein 0.8-1.5 mL of solvent is used for every 1mg of tungsten source;

the substrate is 2 x 3cm SnO doped with fluorine₂Transparent conductive glass;

the solvent thermal reaction is carried out at the temperature of 180 ℃ and 200 ℃ for 12 h;

the purification refers to repeatedly washing the obtained reaction product by absolute ethyl alcohol to obtain W₁₈O₄₉A thin film of nanowires.

6. The composite film according to claim 1, wherein said rare earth doped NaYF₄The particles are obtained by the following method: firstly, mixing rare earth sources A ', B' and C 'and dissolving in solutions D' and E ', heating to dissolve the rare earth sources to obtain a mixed solution, then cooling to room temperature, adding a solution H' dissolving a compound F 'and strong base G' into the mixed solution, then ventilating and heating to discharge methanol, continuing heating to perform high-temperature pyrolysis reaction, and purifying the obtained reaction product after the reaction is finished to obtain the rare earth doped NaYF₄Particles.

7. The composite film with enhanced noble metal/semiconductor-induced upconversion enhancement as claimed in claim 6, wherein the rare earth sources A ', B' and C 'are yttrium chloride hexahydrate, ytterbium chloride hexahydrate and baited chloride hexahydrate respectively, the molar ratio is 1:10:50, the solution D' is 6-8 mL of oleic acid, the solution E 'is 15-20 mL of octadecene, and the compound F' is ammonium fluoride: 4-5.3 mM, wherein the strong base G' is sodium hydroxide: 2.5-3.3 mM, solution H' is methanol: 6-8 mL;

the high-temperature pyrolysis reaction is carried out at 150-350 ℃, the temperature is firstly increased to 150 ℃, the temperature is kept for 20-30min, then the temperature is reduced to room temperature, the temperature is increased to 80 ℃ after 30-40min, the temperature is kept for 1.5-2h, and finally the temperature is continuously increased to 305 ℃, and the temperature is kept for 1.5 h;

the purification means that the obtained reaction product is repeatedly centrifuged and washed by cyclohexane and ethanol solution to obtain the rare earth doped NaYF₄Nanoparticles.

8. Use of the noble metal/semiconductor-induced upconversion-enhanced composite film according to any one of claims 1 to 7 for detecting fluorescent dye molecules.

Technical Field

The invention belongs to the technical field of rare earth doped up-conversion materials, and relates to a composite film with enhanced noble metal/semiconductor induced up-conversion.

Background

In recent years, nano materials with plasma resonance characteristics are widely applied to the research fields of electronics, photonics, catalytic chemistry, nanotechnology, biotechnology and the like, and especially, the realization of high-efficiency luminescence of up-conversion nano materials through local surface plasma resonance characteristic regulation and control of a local field becomes a research hotspot of researchers. When the incident light and the material surface plasmon generate coupling resonance, the incident light localized on the surface leads to the increase of the electric field intensity on the surface of the plasma nanometer material, thereby leading to the increase of the absorption section. The noble metal nano material with strong plasma resonance characteristic has super strong light absorption and scattering to incident light, and is strongly dependent on the size, the shape and the surrounding environment of the nano material, so that the noble metal nano material is a well-known typical plasma nano material for regulating and controlling a local field so as to enhance up-conversion luminescence. The novel plasma matrix material, namely the heavily doped semiconductor nanocrystalline, influences the density of free carriers in the nanomaterial by controlling the doping ratio, and further influences the local surface plasma resonance effect to finally realize the control of upconversion luminescence. Although the local plasma characteristics are utilized in these years to improve the up-conversion luminous efficiency to some extent, due to the limited influence of the 4f-4f transition of lanthanide ions on the extinction coefficient and the excitation band of the rare earth luminescent nano material, the enhancement effect of noble metals and semiconductors with the plasma effect on the luminous efficiency is still not ideal, and how to enhance the local surface plasma effect to further improve the luminous intensity of the up-conversion nano material is always a bottleneck problem in the field.

Disclosure of Invention

To overcome the disadvantages and shortcomings of the prior art, it is a first object of the present invention to provide a composite film with enhanced noble metal/semiconductor induced up-conversion. The second purpose of the invention is to provide the application of the composite film with enhanced noble metal/semiconductor-induced up-conversion in the aspect of detecting fluorescent dye molecules. The composite film with the enhanced noble metal/semiconductor-induced up-conversion is a composite film capable of showing ultra-strong up-conversion luminescence under the excitation of a 980nm laser diode, has simple and flexible process, good stability and high repeatability, and can be used for detecting fluorescent dye molecules. Due to the high-efficiency luminescence property, the method has the potential to be applied to the fields of biological detection, solar cells and the like.

The above purpose of the invention is realized by the following technical scheme:

a composite film with enhanced up-conversion induced by noble metal/semiconductor is composed of Au nano rod as noble metal layer and W as semiconductor layer₁₈O₄₉Nanowire and rare earth doped NaYF (rare earth-doped yttrium fluoride) of conversion luminescent material on luminescent layer₄Particles; three layers are formed finally to form the rare earth doped NaYF₄Au nanorod/W₁₈O₄₉And (3) a nanowire composite film.

The Au nanorod is an Au nanorod with an adjustable plasma resonance position.

The noble metal Au nanorod with the adjustable plasma resonance position is obtained by the following method: the seed solution is prepared by mixing gold source solution A with surfactant solution B, adding reducing agent solution C under vigorous stirring, and standing for 30-40 min; the growth solution is prepared by mixing a surfactant solution B and a surfactant solution D, magnetically stirring for dissolving, cooling, adding a solution E, standing for 15-20min, then adding a gold source solution A, magnetically stirring for 90-120min, introducing a certain volume of inorganic strong acid solution F, adding a strong reducing polyhydroxy solution G, and violently stirring; and finally, injecting a small amount of seed solution into the growth solution to perform seed-mediated reaction, and purifying the obtained reaction product after the reaction is finished to obtain the Au nanorod.

The gold source solution A is tetrachloroauric acid trihydrate (0.5-1 mM), the surfactant solution B is hexadecyl trimethyl ammonium bromide (wherein the concentration of the cetyl trimethyl ammonium bromide in the surfactant solution B in the seed solution is 0.2-0.4M, the concentration of the hexadecyl trimethyl ammonium bromide in the surfactant solution B in the growth solution is 0.037-0.047M), the reducing agent solution C is sodium borohydride (0.01-0.02M), the surfactant solution D is sodium oleate (4mM), the solution E is silver nitrate (4mM), the inorganic strong acid solution F is hydrochloric acid (2-6 mL), and the strong reducing polyhydroxy solution G is ascorbic acid (0.064M).

The seed mediated reaction is carried out at 30 ℃ for 12-14 h.

The purification is to obtain the Au nanorod after the reaction product is centrifuged by ultrapure water and washed.

The semiconductor W₁₈O₄₉The nanowire film is obtained by the following method: dissolving a tungsten source in a solvent, magnetically stirring, transferring into a polytetrafluoroethylene reaction kettle containing a substrate for solvothermal reaction, and purifying the obtained reaction product after the reaction is finished to obtain W₁₈O₄₉A thin film of nanowires.

The tungsten source is tungsten hexacarbonyl (25-30 mg), and the solvent is absolute ethyl alcohol (0.8 mL of solvent is used for each 1mg of tungsten source A).

The substrate is 2 x 3cm SnO doped with fluorine₂Transparent conductive glass (SnO)₂: F) abbreviated to FTO.

The solvent thermal reaction is carried out at 180 ℃ and 200 ℃ for 12 h.

The purification refers to repeatedly washing the obtained reaction product by absolute ethyl alcohol to obtain W₁₈O₄₉A thin film of nanowires.

The rare earth doped NaYF₄The particles are obtained by the following method: firstly, mixing rare earth sources A ', B' and C 'and dissolving in solutions D' and E ', heating to dissolve the rare earth sources to obtain a mixed solution, then cooling to room temperature, adding a solution H' dissolving a compound F 'and strong base G' into the mixed solution, then ventilating and heating to discharge methanol, continuing heating to perform high-temperature pyrolysis reaction, and purifying the obtained reaction product after the reaction is finished to obtain the rare earth doped NaYF₄Particles.

The rare earth sources A ', B' and C 'are respectively yttrium chloride hexahydrate, ytterbium chloride hexahydrate and bait chloride hexahydrate (the molar ratio is 1:10:50), the solution D' is oleic acid (6-8 mL), the solution E 'is octadecene (15-20 mL), the compound F' is ammonium fluoride (4-5.3 mM), the strong base G 'is sodium hydroxide (2.5-3.3 mM), and the solution H' is methanol (6-8 mL).

The high-temperature pyrolysis reaction is carried out at 150-350 ℃, the temperature is firstly increased to 150 ℃ and is kept for 20-30min, then the temperature is reduced to room temperature, the temperature is increased to 80 ℃ after 30-40min and is kept for 1.5-2h, and finally the temperature is continuously increased to 305 ℃ and is kept for 1.5 h.

The purification means that the obtained reaction product is repeatedly centrifuged and washed by cyclohexane and ethanol solution to obtain the rare earth doped NaYF₄Nanoparticles.

A preparation method of the composite film with enhanced noble metal/semiconductor induced up-conversion specifically comprises the following steps:

(1) dispersing the Au nanorod solution into the solvent A, and then dispersing W₁₈O₄₉The nanowire film is immersed in the solvent A to carry out a simple self-assembly process to obtain the Au nanorod/W₁₈O₄₉A nanowire film;

(2) dispersing rare earth doped NaYF into solvent B₄Solution, and then Au nanorod/W obtained in the step (1)₁₈O₄₉Immersing the nanowire film in a solvent B to perform a secondary simple self-assembly process to obtain the rare earth doped NaYF₄Au nanorod/W₁₈O₄₉A thin film of nanowires.

Further, the preferred plasma resonance position of the Au nanorod solution in the step (1) is 980 nm;

further, the solvent A in the step (1) is ultrapure water, and the solvent B in the step (2) is cyclohexane.

Further, the simple self-assembly processes in the steps (1) and (2) are both kept at 50 ℃ for 6 hours.

The length-diameter ratio of the noble metal Au nanorod is controlled to adjust the resonance position of the surface plasma to be matched with the wavelength (980nm) of an excitation light source for up-conversion luminescence, and the Au nanorod and the W nanorod₁₈O₄₉After the surface plasma coupling of the nano wire, the nano wire is doped with adjacent rare earth NaYF₄Excited emission wave of nanoparticlesThe long overlap causes a significant increase in the local electromagnetic field strength around, which in turn results in rare earth doped NaYF₄The upconversion luminescence of the nanoparticles is greatly enhanced. The fluorescent dye molecule can be detected by utilizing the strong luminescence of the composite film and the fluorescence resonance energy transfer of the fluorescent dye molecule.

The composite film with the enhanced noble metal/semiconductor induced up-conversion has stronger extinction performance in visible and near-infrared regions, and is doped with rare earth NaYF₄The excitation and emission spectra of the nanoparticles overlap well, so that the efficient upconversion luminescence enhancement is shown, and the method can be applied to the detection of fluorescent dye molecules, and can also be applied to the fields of biological detection, solar cells and the like due to the superiority of the upconversion nanomaterial.

Compared with the prior art, the invention has the beneficial effects that:

(1) the composite film has the advantages of simple preparation process, no toxicity, good stability and high repeatability, and can emit bright green up-conversion luminescence visible to human eyes under the excitation of a 980nm laser diode.

(2) The technical scheme of the invention can realize that the length-diameter ratio of the Au nanorod is adjustable, namely the resonance position of the surface plasma is adjustable by controlling the mole number of the hexadecyl trimethyl ammonium bromide solution and the volume number of the hydrochloric acid in the growth solution.

(3) The invention adjusts the surface plasma resonance position of the Au nano rod to be consistent with the wavelength position of an excitation light source, and then the surface plasma resonance position of the Au nano rod is consistent with the W with wider surface plasma resonance characteristic₁₈O₄₉The nanowires are assembled and compounded, the coupled strong surface plasmon resonance greatly improves a local electromagnetic field, up-conversion luminescence enhancement is realized, and the composite luminescent film can be applied to the application of detecting fluorescent dye molecule rhodamine 6G (R6G). Such as: biological detection, solar cells, and the like.

Drawings

FIG. 1 is a scanning electron microscope of Au nanorods prepared in example 5.

FIG. 2 shows W prepared in example 8₁₈O₄₉Scanning electron microscopy of nanowires.

FIG. 3 is a rare earth doped NaYF prepared in example 8₄Scanning electron microscopy of nanoparticles.

FIG. 4 is the Au nanorod/W prepared in example 8₁₈O₄₉Scanning electron microscopy of thin films of nanowires.

FIG. 5 is a rare earth doped NaYF prepared in example 8₄Au nanorod/W₁₈O₄₉Scanning electron microscopy of thin films of nanowires.

FIG. 6 is an extinction spectrum of Au nanorods at different surface plasmon resonance positions prepared in examples 1-7.

FIG. 7 shows Au nanorods and W prepared in example 8₁₈O₄₉Nanowire and Au nanorod/W₁₈O₄₉Extinction spectra of nanowires.

FIG. 8 shows the rare earth doped NaYF prepared in example 8 and comparative example 1₄Rare earth doped NaYF₄/W₁₈O₄₉Nanowire and rare earth doped NaYF₄Au nanorod and rare earth doped NaYF₄Au nanorod/W₁₈O₄₉The fluorescence spectrum of the nanowire film is obtained under the excitation of 980 nm.

FIG. 9 is a rare earth doped NaYF prepared in example 8₄Au nanorod/W₁₈O₄₉The nanowire film has upconversion luminescence spectrum excited by 980nm laser under different R6G dye concentrations.

FIG. 10 is a graph of luminescence of a composite film of the present invention converted under excitation of a 980nm laser diode.

Detailed Description

The invention is described in more detail below with reference to specific examples, without limiting the scope of the invention. Unless otherwise specified, the experimental methods adopted by the invention are all conventional methods, and experimental equipment, materials, reagents and the like used in the experimental method can be obtained from commercial sources.