CN112898969A - Application of fluorescent carbon dots in fields of illumination, ion detection and temperature sensing - Google Patents

Abstract

The invention relates to the field of fluorescent nano materials, in particular to application of fluorescent carbon dots in the fields of illumination, ion detection and temperature sensingThe fluorescent carbon dots are prepared by taking 2, 5-diaminobenzene sulfonic acid as a raw material and modulating three different solvents of formamide, N-methylpyrrolidone and dimethylformamide; can be used for preparing LED lighting devices and Ag⁺And Fe³⁺An ion detection sensor and a temperature sensor. The fluorescent powder keeps good fluorescence performance, especially the white fluorescent powder can achieve emission of nearly pure white light, CIE coordinates 1931(0.31, 0.32) can be well applied to LED illumination, and meanwhile, the sensors provided based on B-CDs, G-CDs and R-CDs can well detect Ag⁺And Fe³⁺And has good selectivity and interference resistance.

Description

Application of fluorescent carbon dots in fields of illumination, ion detection and temperature sensing

Technical Field

The invention relates to the field of fluorescent nano materials, in particular to application of fluorescent carbon dots in the fields of illumination, ion detection and temperature sensing.

Background

As a novel nano material in a carbon family, the carbon dots attract wide attention of people due to the advantages of rich raw material resources, low price, easy obtainment, low toxicity, strong photobleaching resistance, good water solubility, good biocompatibility and the like. At present, a plurality of carbon dots are applied to a plurality of fields such as biological markers, drug targeting, cell imaging and the like.

Disclosure of Invention

The invention provides application of fluorescent carbon dots in the fields of illumination, ion detection and temperature sensing.

In order to achieve the purpose, the invention adopts the technical scheme that:

the fluorescent carbon dots are three primary colors fluorescent carbon dots, consist of B-CDs and G-CDs, R-CDs, and can be used for preparing LED lighting devices, ion detection sensors and temperature sensors.

The trichromatic fluorescent carbon dot is prepared by using 2, 5-diaminobenzene sulfonic acid as a raw material and regulating three different solvents, namely formamide, N-methylpyrrolidone and dimethylformamide.

When the fluorescent carbon dots are used for preparing an LED lighting device, the method comprises the following steps:

s1, taking 3ml of 0.5mg/ml three-primary-color carbon dot alcohol solution and 1G of edible lotus root starch, ultrasonically mixing, and then drying at a constant temperature of 60 ℃ to obtain fluorescent CDs-lotus root starch composite powder which is named as B-CDs-1, G-CDs-1 and R-CDs-1 respectively;

s2, mixing B-CDs-1, G-CDs-1 and R-CDs-1 in a mass ratio of 1:3:5 to obtain white light-emitting W-CDs-1.

The fluorescent carbon dots can be used for preparing Ag⁺And Fe³⁺The three CDs have high sensitivity, and can selectively identify Ag⁺And Fe³⁺Ionic LODs can reach 35 and 23nM, respectively.

The invention has the following beneficial effects:

the fluorescent powder keeps good fluorescence performance, especially the white fluorescent powder can achieve emission of nearly pure white light, CIE coordinates 1931(0.31, 0.32) can be well applied to LED illumination, and meanwhile, the sensors provided based on B-CDs, G-CDs and R-CDs can well detect Ag⁺And Fe³⁺And has good selectivity and interference resistance.

Drawings

FIG. 1 shows the UV-VIS absorption spectrum and the fluorescence spectrum of B-CDs;

in the figure: (a) the ultraviolet-visible absorption spectrum and the fluorescence spectrum of B-CDs; (b) is the fluorescence spectrum of B-CDs at different excitation wavelengths (Ex at 330-450 nm).

FIG. 2 is a graph showing the UV-VIS absorption spectrum and the fluorescence spectrum of G-CDs;

in the figure: (a) the ultraviolet-visible absorption spectrum and the fluorescence spectrum of G-CDs; (b) is the fluorescence spectrum of B-CDs at different excitation wavelengths (Ex at 340-.

FIG. 3 is a UV-VIS absorption spectrum and a fluorescence spectrum of R-CDs;

in the figure: (a) the ultraviolet-visible absorption spectrum and the fluorescence spectrum of the R-CDs; (b) is the fluorescence spectrum of B-CDs at different excitation wavelengths (Ex at 440-580 nm).

FIG. 4 is a normalized fluorescence spectrum of R-CDs, G-CDs, and B-CDs.

FIG. 5 shows the CIE (1931) coordinates of B-CDs, G-CDs, R-CDs and W-CDs.

FIG. 6 is a fluorescence spectrum of W-CDs;

in the figure: the insets are photographs of W-CDs under fluorescent light (left) and 365nm (right), respectively.

FIG. 7 is a fluorescence spectrum of a fluorescent powder and a fluorescent gel;

in the figure: a is a fluorescent powder and b is a fluorescent gel.

FIG. 8 is the CIE coordinates of the phosphor powder.

FIG. 9 shows a fluorescence spectrum and a photograph of fluorescent powder W-CD-1.

FIG. 10 is the CIE coordinates of the fluorescent gel.

FIG. 11 shows a fluorescence spectrum and an optical photograph of the fluorescent powder W-CD-1, a photograph under a fluorescent lamp (left) and a photograph under 365nm (right).

FIG. 12 shows B-CDs vs Ag⁺Sensing of (2). In the figure: a is with Ag⁺Increase in concentration (0-1.3. mu.M), change in fluorescence pattern of the solution. b is a fluorescence recovery factor (I)₀-I/I₀) And Ag⁺Concentration dependence is shown by the fluorescent recovery factor (I)₀-I/I₀) And Ag⁺Linear dependence of concentration (Ag)⁺The concentration is 0-0.7. mu.M).

FIG. 13 shows B-CDs vs Fe³⁺Sensing of (2). In the figure: a is with Fe³⁺The increase in concentration is shown by the fluorescence spectrum, and b is shown by the linear relationship.

FIG. 14 shows G-CDs vs Ag⁺Sensing of (2). In the figure: a is with Ag⁺Increase in concentration (0-1.3. mu.M), change in fluorescence pattern of the solution. b is a fluorescence recovery factor (I)₀-I/I₀) And Ag⁺A graph of concentration dependence; inset is fluorescence recovery factor (I)₀-I/I₀) And Ag⁺Linear dependence of concentration (Ag)⁺The concentration is 0-0.7. mu.M).

FIG. 15 is G-CDs vs Fe³⁺Sensing of (2). a is with Fe³⁺Increase in concentration (0-1.3. mu.M), change in fluorescence pattern of the solution. b is a linear relation graph.

FIG. 16 shows R-CDs vs Ag⁺Sensing of (2). In the figure: a is with Ag⁺Increase in concentration (0-1.3. mu.M), change in fluorescence profile of the solution; b is a fluorescence recovery factor (I)₀-I/I₀) And Ag⁺A graph of concentration dependence; inset is fluorescence recovery factor (I)₀-I/I₀) And Ag⁺Linear dependence of concentration (Ag)⁺The concentration is 0-0.7. mu.M).

FIG. 17 is R-CDs vs Fe³⁺Sensing of (2). a is with Fe³⁺Increase in concentration (0-1.3. mu.M), change in fluorescence pattern of the solution. b is a linear relation graph.

FIG. 18 shows the comparison of B-CDs, G-CDs and R-CDs against Ag, respectively⁺(a) And Fe³⁺(b) Selectivity of (2)And determination of interference immunity;

in the figure: (1) B-CDs vs Ag⁺(a) And Fe³⁺(b) Selectivity and interference immunity; (2) G-CDs vs Ag⁺(a) And Fe³⁺(b) Selectivity and interference immunity; (3) R-CDs to Ag⁺(a) And Fe³⁺(b) Selectivity and interference immunity.

FIG. 19 is a graph showing the temperature sensing performance of G-CDs.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

LED lighting applications:

2, 5-diaminobenzene sulfonic acid is used as a source to synthesize CDs with different fluorescence by adopting a one-step hydrothermal method. The synthesis method comprises the following steps: respectively adding 25mg of 2, 5-diaminobenzene sulfonic acid, 10ml of solvent formamide, 10ml of solvent NMP and 10ml of solvent DMF into 3 stainless steel reaction kettles of 25ml, reacting in a constant-temperature oven at 180 ℃ for 8 hours, cooling the prepared quantum dots to room temperature, eluting by using a mixed solvent of methanol and dichloromethane as an eluent through silica gel column chromatography, removing the solvent, and freeze-drying to obtain CDs with different luminosities; red fluorescent CDs prepared with DMF as solvent were named (R-CDs), green fluorescent CDs prepared with NMP as solvent were named (G-CDs), and blue fluorescent CDs prepared with formamide as solvent were named (B-CDs). The prepared CDs have higher quantum yield, wherein the quantum yield is 41 percent of B-CDs, 33 percent of G-CDs and 39.3 percent of R-CDs, and the CIE coordinates are respectively B-CDs (0.16, 0.15), G-CDs (0.36, 0.57) and R-CDs (0.68, 0.32). It can be seen that the three colors of CDs prepared have a large overlap (normalized spectrum), and the white-emitting W-CDs are obtained by mixing in the ratio of B-CD: G-CD: R-CD ═ 1:3: 5. The CIE coordinates of CDs (W-CDs) modulated with the prepared CDs and having white fluorescence were (0.32, 033).

Taking 3ml of 0.5mg/ml three-primary-color carbon dot alcohol solution and 1G of edible lotus root starch, ultrasonically mixing, and then drying at the constant temperature of 60 ℃ to obtain fluorescent powder of CDs-lotus root starch with fluorescence, wherein the fluorescent powder is named as B-CDs-1, G-CDs-1 and R-CDs-1 respectively;

preparation of fluorescent gel: adding 3G G-CDs-1 or R-CDs-1 or B-CDs-1 into 30ml of deionized water, heating and stirring in a water bath at 90 ℃ for 2h, cooling to room temperature, and freeze-drying to obtain fluorescent gels which are named as B-CDs-2, G-CDs-2 and R-CDs-2 respectively;

green and environment-friendly CDs fluorescent powder and fluorescent gel CDs are synthesized, corresponding to CIE (1931) coordinates of the fluorescent powder as B-CDs-1(0.16,0.08), G-CDs-1(0.19, 0.35) and R-CDs-1(0.62, 0.38), and CIE (1931) coordinates of the fluorescent gel as B-CDs-2(0.16, 0.07), G-CDs-2(0.22, 0.37) and R-CDs-2(0.62, 0.38). The CIE coordinates of the white light materials W-CDs-1 and W-CDs-2 can reach (0.31, 032), (0.33, 0.35).

An ion detection sensor:

B-CDs, G-CDs and R-CDs for Ag⁺And Fe³⁺The assay of (2) was performed at room temperature, 3ml of a 0.5mg/ml dispersion of R-CDs in methanol (3ml of a 0.5mg/ml dispersion of G-CDs or 3ml of a 0.5mg/ml dispersion of B-CDs in deionized water), followed by addition of various concentrations of Ag⁺Or Fe³⁺And (3) uniformly mixing the standard substance at room temperature, recording the fluorescence spectrum of the solution after 1min, adding other ions into the B-CDs, the G-CDs and the R-CDs under the same condition to measure selectivity and interference resistance, and keeping parameters unchanged in the measuring process.

As shown in FIG. 3, the strong fluorescence emitted by B-CDs at 450nm can follow Ag under excitation at 396nm⁺Or Fe³⁺Is quenched when the Ag is added gradually⁺At a concentration of 0-1. mu.M, (I)₀-I/I₀) And Ag⁺Has a good linear relation with the linear equation of y being 0.434x +0.0168 (R)²0.991, n 13), for Ag⁺The detection limit of (2) was as low as 69nM (3. sigma./K) (σ is the standard deviation after correction of blank signal, K is the slope of the fitted line). When Fe³⁺At concentrations of 0-1.3. mu.M, a linear relationship y of 0.484x +0.0074 (R)²0.999, n 13) with a detection limit of 62nM。

Same R-CDs for Fe³⁺And Ag⁺Also shows high detectability, under the excitation of 550nm, the fluorescence of R-CDs at about 635nm is accompanied with Ag⁺Or Fe³⁺The concentration of Ag is shown in the figure⁺And Fe³⁺At concentrations of 0-1.5. mu.M and 0-0.5. mu.M, respectively, (I)₀-I/I₀) And Ag⁺Or Fe³⁺Has a linear relationship of y 0.314x +0.0181 (R)²0.991, n 13) and y 1.317x +0.00512(R2 0.995, n 13), for Ag⁺And Fe³⁺The detection limits (3. sigma./K) of (D) were 95nM and 23nM, respectively.

G-CDs vs Ag⁺And Fe³+ detection when Ag is shown in FIGS. 14 and 15⁺At a concentration of 0-0.7. mu.M, (I)₀-I/I₀) And Ag⁺Has a linear relationship of y-0.8465 x +0.1356 (R)²0.99, n 13), detection limit 35nM (3 σ/K) (σ is the standard deviation after correction of blank signal, K is the slope of the fitted line). When Fe³⁺At concentrations of 0-3 μ M, a linear relationship y of 0.221x +0.0963 (R) exists²0.992, n 13) with a detection limit of 136 nM.

Same R-CDs for Fe³⁺And Ag⁺Also shows high detectability, under the excitation of 550nm, the fluorescence of R-CDs at about 635nm is accompanied with Ag⁺Or Fe³⁺The concentration of Ag is shown in the figure⁺Or Fe³⁺At concentrations of 0-1.5. mu.M and 0-0.5. mu.M, respectively, (I)₀-I/I₀) And Ag⁺Or Fe³⁺Has a linear relationship of y 0.314x +0.0181 (R)²0.991, n 13) and y 1.317x +0.00512(R2 0.995, n 13), for Ag⁺Or Fe³⁺The detection limits (3. sigma./K) of (D) were 95nM and 23nM, respectively.

And (3) selectivity: to test the selectivity and the immunity of the proposed sensor, Cd in the presence of a representative ion^{2 +},Na⁺,Cu²⁺,Zn²⁺,Mg²⁺,Hg⁺,Ni²⁺,NH₄ ⁺,Co²⁺,Al³⁺,Mn²⁺The ions were subjected to a selective measurement,the selectivity and interference of the anti-interference measurements at multiple quenching concentrations (50. mu.M) are shown in FIG. 18 for PL intensities relative to three pure CDs, and it can be seen that the addition of Fe³⁺Or Ag⁺Then, the fluorescence intensity of the solution is obviously reduced, and other ions have no change or little change. The results show that the synthesized B-CDs, G-CDs and R-CDs only show Fe³⁺And Ag⁺Can be developed into Ag⁺And Fe³⁺High efficiency fluorescent sensors for ions.

A temperature sensor:

for the mechanical measurement capability of concept verification, the temperature sensing application of G-CDs is carried out. As shown in fig. 19(a), G-CDs has good temperature sensing performance. When the temperature is 10-60 ℃, the fluorescence intensity of the solution is gradually reduced along with the rise of the temperature; there is a linear relationship between fluorescence intensity and temperature (fig. 19b, y ═ 0.0051x +0.0415(R2 ═ 0.994)). The temperature sensing function can be maintained for at least 5 cycles (10-60 ℃, fig. 19 c).

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims (4)

1. The fluorescent carbon dots are applied to the fields of illumination, ion detection and temperature sensing, and are characterized in that: the fluorescent carbon dots are three primary color fluorescent carbon dots, are composed of B-CDs and G-CDs and R-CDs, and can be used for preparing LED lighting devices, ion detection sensors and temperature sensors.

2. The use of claim 1, wherein: the trichromatic fluorescent carbon dot is prepared by using 2, 5-diaminobenzene sulfonic acid as a raw material and regulating three different solvents, namely formamide, N-methylpyrrolidone and dimethylformamide.

3. The use of claim 1, wherein: when the LED illuminating device is prepared, the method comprises the following steps:

s1, respectively taking 3ml of 0.5mg/ml B-CDs and G-CDs, respectively taking an R-CDs alcohol solution and 1G of edible lotus root starch, ultrasonically mixing, and then drying at the constant temperature of 60 ℃ to obtain fluorescent CDs-lotus root starch composite powder, wherein the fluorescent CDs-lotus root starch composite powder is named as B-CDs-1, G-CDs-1 and R-CDs-1 respectively;

s2, mixing B-CDs-1, G-CDs-1 and R-CDs-1 in a mass ratio of 1:3:5 to obtain white light-emitting W-CDs-1.

4. The use of claim 1, wherein: can be used for preparing Ag⁺And Fe³⁺High efficiency fluorescent sensors for ions.

Images