WO2016053411A1 - Bandgap engineering of carbon quantum dots - Google Patents
Bandgap engineering of carbon quantum dots Download PDFInfo
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- WO2016053411A1 WO2016053411A1 PCT/US2015/036729 US2015036729W WO2016053411A1 WO 2016053411 A1 WO2016053411 A1 WO 2016053411A1 US 2015036729 W US2015036729 W US 2015036729W WO 2016053411 A1 WO2016053411 A1 WO 2016053411A1
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- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
Definitions
- the present disclosure pertains to scalable methods of producing carbon quantum dots with desired bandgaps.
- the methods of the present disclosure include a step of exposing a carbon source to an oxidant at a reaction temperature, where the exposing results in the formation of the carbon quantum dots.
- the methods of the present disclosure also include a step of selecting a desired size of the formed carbon quantum dots.
- the desired size of carbon quantum dots includes a size range. In some embodiments, the desired size of the carbon quantum dots ranges from about 1 nm to about 200 nm in diameter, from about 1 nm to about 100 nm in diameter, or from about 2 nm to about 80 nm in diameter.
- carbon quantum dot size selection occurs by selecting the reaction temperature that produces the desired size of the formed carbon quantum dots.
- the selected reaction temperature is a set temperature that remains constant during the exposing step.
- the selected reaction temperature is a temperature gradient that gradually increases or decreases during the exposing step.
- the selected reaction temperature ranges from about 25 °C to about 200 °C, from about 50 °C to about 150 °C, or from about 100 °C to about 150 °C.
- the desired size of the carbon quantum dots decreases as the selected reaction temperature increases.
- carbon quantum dot size selection occurs by separating the desired size of the formed carbon quantum dots from other formed carbon quantum dots.
- the separation occurs by filtration, such as cross-flow ultrafiltration.
- the filtration occurs sequentially through multiple porous membranes that have different pore sizes.
- the separation occurs through dialysis or repetitive dialyses.
- the carbon source that is used to make carbon quantum dots includes, without limitation, coal, coke, graphite, carbon nanotubes, activated carbon, carbon black, fullerenes, and combinations thereof.
- the oxidant that is exposed to the carbon source includes an acid, such as sulfuric acid, nitric acid, and combinations thereof.
- the methods of the present disclosure also include a step of purifying the formed carbon quantum dots.
- the purifying step includes, without limitation, extraction, filtration, evaporation, precipitation, dialysis, and combinations thereof.
- the methods of the present disclosure also include a step of enhancing the quantum yield of the formed carbon quantum dots.
- the enhancing occurs by hydrothermal treatment of the carbon quantum dots, treatment of the carbon quantum dots with one or more bases, treatment of the carbon quantum dots with one or more hydroxides, treatment of the carbon quantum dots with one or more dopants, treatment of the carbon quantum dots with one or more reducing agents, and combinations thereof.
- the methods of the present disclosure can be utilized to produce various types of carbon quantum dots with various desired bandgaps.
- the formed carbon quantum dots include graphene quantum dots.
- the formed carbon quantum dots have a crystalline hexagonal structure.
- the formed carbon quantum dots are photoluminescent.
- the formed carbon quantum dots are functionalized with a plurality of functional groups.
- the formed carbon quantum dots are edge functionalized.
- the methods of the present disclosure can also be used to produce carbon quantum dots in a scalable manner.
- the methods of the present disclosure form carbon quantum dots in bulk quantities that range from about 1 g of carbon quantum dots to about 10 tons of carbon quantum dots.
- FIGURE 1 provides a scheme of a method of making carbon quantum dots (CQDs) with desired bandgaps through size selection.
- CQDs carbon quantum dots
- FIGURE 2 provides illustrations and data relating to the production and size-separation of graphene quantum dots (GQDs).
- FIG. 2A is a schematic illustration of GQD synthesis.
- FIG. 2B is a schematic illustration of the separation of GQDs using cross-flow ultrafiltration. Transmission electron microscopy (TEM) images of the separated GQDs are also shown, including GQDs-S4.5 (FIG. 2C), GQDs-S16 (FIG. 2D), GQDs-S41 (FIG. 2E) and GQDs-S70 (FIG. 2F).
- FIG. 2G provides a summary of size distributions of GQDs-S4.5, GQDs-S16, GQDs-S41 and GQDs-S70, as determined by TEM.
- FIGURE 3 provides the hydrodynamic diameters of GQDs at different sizes obtained from dynamic light scattering (DLS).
- the legend sizes are listed so as to be consistent with the TEM legend in FIG. 2G. However, the actual DLS recorded average sizes are 10 + 2.5, 27 + 7.9, 41 + 11 and 76 + 18 nm, respectively.
- FIGURE 4 provides direct C pulse magic-angle spinning nuclear magnetic resonance (MAS NMR) (FIG. 4A) and cross-polarization 13 C MAS NMR (FIG. 4B) spectra of GQDs- S4.5, GQDs-S16, GQDs-S41 and GQDs-S70.
- MAS NMR direct C pulse magic-angle spinning nuclear magnetic resonance
- FIG. 4B cross-polarization 13 C MAS NMR
- FIGURE 5 provides various data relating to synthesized GQDs.
- FIG. 5A provides an X- ray photoelectron spectroscopy (XPS) survey of GQDs-S4.5, GQDs-S16, GQDs-S41 and GQDs- S70 with Au as the reference. Cls high resolution XPS spectra of GQDs-S4.5 (FIG. 5B), GQDs-S16 (FIG. 5C), GQDs-S41 (FIG. 5D) and GQDs-S70 (FIG. 5E) are also shown.
- FIG. 5F provides a summary of percentage elemental contents in different functional groups from FIGS. 5B-5E.
- FIGURE 6 provides solid state Fourier transform infrared (FTIR) spectra of GQDs-S4.5
- FIG. 6A GQDs-S16 (FIG. 6B), GQDs-S41 (FIG. 6C), and GQDs-S70 (FIG. 6D).
- FIGURE 7 provides UV-Vis absorption of GQDs-S4.5, GQDs-S16, GQDs-S41 and
- FIGURE 8 provides 2-D excitation-emission contour maps of GQDs-S4.5 (FIG. 8A), GQDs-S16 (FIG. 8B), GQDs-S41 (FIG. 8C) and GQDs-S70 (FIG. 8D), all at ⁇ 80 mg/L in water at pH 6.
- FIG. 8E is a normalized intensity scale bar for FIGS. 8A-D.
- FIG. 8F is a solution of GQDs under 365 nm excitation UV lamp. From left to right, the vials contain solutions of GQDs-S4.5, GQDs-S16, GQDs-S41, and GQDs-S70, respectively.
- FIG. 8G compares the relationship between the optical bandgap and GQD size (from TEM) or membrane pore sizes used in the ultrafiltration.
- FIGURE 9 provides a comparison of the photoluminescence of GQDs-S4.5 before and after NaOH or Na 2 S treatment.
- FIGURE 10 provides Cls high resolution XPS spectra of GQDs-T150-7.6 (FIG. 10A), GQDs-T130-25 (FIG. 10B), GQDs-Tl 10-27 (FIG. IOC), and GQDs-T50-54 (FIG. 10D).
- FIG. 10E provides a summary of percentage elemental contents in different functional groups from FIGS. 10A-D.
- FIGURE 11 provides TEM images of GQDs synthesized at different temperatures, including GQDs-T150-7.6 (FIG. 11A), GQDs-T130-25 (FIG. 11B), GQDs-Tl 10-27 (FIG.
- FIG. HE provides a summary of size distributions of GQDs from FIGS. 11A-11D.
- FIGURE 12 provides matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) of GQDs synthesized at different temperatures.
- the average diameter of the GQDs was 54 + 7.2, 27 + 3.8, 25 + 5.0, and 7.6 + 1.8 nm as the synthesis temperature rose from 50 °C to 150 °C (from top to bottom in the Figure).
- the corresponding molecular weights of the GQDs peaks were 60, 49, 44 and 27 kD, respectively.
- FIGURE 13 provides a composite plot of FIGS. 2G and 9E.
- GQDs-T100-35 is composed of GQDs-S4.5, GQDs-S16, GQDs-S41 and GQDs-S70. Comparing all the GQDs synthesized at different temperatures, GQDs-T100-35 contains particles at sizes between 4.5 nm and 80 nm, but the amounts are small. The main trend is that, as the temperature increases, the major peaks shift to the lower diameters.
- FIGURE 14 provides direct 13 C pulse MAS NMR (FIG. 14A) and cross-polarization 13 C MAS NMR spectra (FIG. 14B) of GQDs-T50-54, GQDs-Tl 10-27, GQDs-T130-25 and GQDs- T150-7.6.
- the cross-polarization spectrum of GQD-T110-27 shows enhancement due to aliphatic impurities.
- FIGURE 15 provides UV-Vis absorption of GQDs-T150-7.6, GQDs-T130-25, GQDs- Tl 10-27 and GQDs-T50-54.
- FIGURE 16 provides 2D excitation-emission contour map of GQDs-T150-7.6 (FIG. 16A), GQDs-T130-25 (FIG. 16B), GQDs-Tl 10-27 (FIG. 16C), and GQDs-T50-54 (FIG. 16D).
- the normalized scale bar is shown in (FIG. 16E). The concentration is ⁇ 30 mg/L at ⁇ pH 6.
- FIG. 16F provides GQDs solutions under a 365 nm excitation UV lamp. The solutions from left to right are GQDs-T150-7.6, GQDs-T130-25, GQDs-Tl 10-27 and GQDs-T50-54.
- FIG. 16G provides a summary of the peak intensities at 300 nm and 320 nm excitation wavelengths from FIGS. 16A-D.
- FIGURE 17 provides an emission spectrum of GQDs synthesized from bituminous coal at 120 °C (excited at 345 nm).
- the inset shows the GQDs solution under a 365 nm UV lamp.
- FIGURE 18 shows the emission spectra of GQDs synthesized at 130 °C for 1 hour and 6 hours. The spectra were excited at 325 nm (FIG. 18A) and 365 nm (FIG. 18B).
- FIGURE 19 provides FTIR (FIG. 19A), Raman (FIG. 19B), and XRD (FIG. 19C) spectra of anthracite and graphite.
- the Raman spectrum the larger D peak at 1350 cm "1 of anthracite indicates a higher defect.
- the d-spacing for anthracite and graphite was 0.346 nm and 0.337 nm, respectively.
- the broader peak at -26° for anthracite indicates a smaller crystalline domain.
- CQDs luminescent carbon-based quantum dots
- methods for preparing CQDs with specific bandgaps have been developed. For instance, methods of producing CQDs with specific bandgaps have been developed by the use of chromatography with gradient elution of different mobile phases, cutting of tattered graphite using amines, and element-doping of as-prepared CQDs.
- complex separation techniques, multi-step syntheses or high reagent costs have limited the scalable production of CQDs with desired bandgaps. As such, a need exists for improved methods of producing CQDs with desired bandgaps.
- Various embodiments of the present disclosure address this need.
- the present disclosure provides a scalable method for producing carbon quantum dots with desired bandgaps.
- the methods of the present disclosure include: exposing a carbon source to an oxidant at a reaction temperature (step 10), where the exposing results in formation of the carbon quantum dots (step 12).
- the methods of the present disclosure also include a step of purifying the formed quantum dots (step 14).
- the methods of the present disclosure also include a step of selecting a desired size of the formed carbon quantum dots (step 16).
- the carbon quantum dot size selection occurs by separating the desired size of the formed carbon quantum dots from other formed carbon quantum dots (step 18), selecting the reaction temperature that produces the desired size of the formed carbon quantum dots (step 20), and combinations of such steps.
- the oxidant includes an acid.
- the acid includes, without limitation, sulfuric acid, nitric acid, phosphoric acid, hypophosphorous acid, fuming sulfuric acid, hydrochloric acid, oleum, sulfur trioxide in sulfuric acid, chlorosulfonic acid, and combinations thereof.
- the oxidant utilized to form carbon quantum dots is a mixture of sulfuric acid and nitric acid.
- the oxidant is nitric acid.
- the oxidant only consists of nitric acid.
- the oxidant includes, without limitation, potassium permanganate, sodium permanganate, sodium nitrate, hypophosphorous acid, nitric acid, sulfuric acid, hydrogen peroxide, and combinations thereof.
- the oxidant is a mixture of potassium permanganate, sulfuric acid, and hypophosphorous acid.
- the oxidant includes 20% fuming sulfuric acid.
- the oxidant includes 98% sulfuric acid.
- the oxidant is a combination of sodium nitrate and nitric acid. The utilization of additional oxidants can also be envisioned.
- the methods of the present disclosure may utilize various types of carbon sources to form carbon quantum dots.
- the carbon sources include, without limitation, coal, coke, graphite, carbon nanotubes, activated carbon, carbon black, fullerenes, and combinations thereof.
- the carbon source includes coal.
- coal Various types of coals may be utilized as carbon sources to form carbon quantum dots.
- the coal includes, without limitation, anthracite, bituminous coal, sub-bituminous coal, metamorphically altered bituminous coal, asphaltenes, asphalt, peat, lignite, steam coal, petrified oil, and combinations thereof.
- the carbon source includes anthracite.
- the carbon source includes bituminous coal. The use of additional coals as carbon sources can also be envisioned.
- the carbon source includes coke. In some embodiments the coke is made from pitch. In some embodiments, the coke is made from bituminous coals. In some embodiments, the coke is made from pitch and bituminous coals. In some embodiments, the carbon source is a combination of coke and coal. The use of additional carbon sources can also be envisioned.
- the exposing occurs in a solution that contains the oxidant.
- the exposing includes sonicating the carbon source in the presence of an oxidant.
- the exposing includes stirring a carbon source in the presence of an oxidant.
- the exposing includes heating the carbon source in the presence of an oxidant at a reaction temperature.
- the reaction temperature is at least about 100 °C. In some embodiments, the reaction temperature ranges from about 100 °C to about 150 °C.
- Carbon sources may be exposed to oxidants for various periods of time. For instance, in some embodiments, the exposing occurs from about 1 minute to about 48 hours. In some embodiments, the exposing occurs from about 1 hour to about 24 hours. In some embodiments, the exposing occurs from about 15 hours to about 24 hours.
- two or more oxidants may be exposed to the carbon source in a sequential manner. For instance, in some embodiments, a first oxidant is mixed with a carbon source. Thereafter, a second oxidant is mixed with the carbon source. In some embodiments, the first oxidant is sulfuric acid and the second oxidant is nitric acid. [0049] In some embodiments, a single oxidant is exposed to a carbon source. In some embodiments, the single oxidant is nitric acid. Additional methods of exposing carbon sources to oxidants can also be envisioned.
- the methods of the present disclosure can be used to form various types of carbon quantum dots. Further embodiments of the present disclosure pertain to the formed carbon quantum dots.
- the carbon quantum dots of the present disclosure are in pristine form. In some embodiments, the carbon quantum dots of the present disclosure are un- functionalized. In some embodiments, the carbon quantum dots of the present disclosure are functionalized with a plurality of functional groups. In some embodiments, the functional groups include, without limitation, amorphous carbon, oxygen groups, carbonyl groups, carboxyl groups, aromatic groups, alkane groups, alkene groups, ketone groups, esters, amines, amides, and combinations thereof.
- the carbon quantum dots of the present disclosure are edge functionalized with a plurality of functional groups.
- the carbon quantum dots of the present disclosure include oxygen addends on their edges.
- the carbon quantum dots of the present disclosure include amorphous carbon addends on their edges.
- the carbon quantum dots of the present disclosure include graphene quantum dots.
- the carbon quantum dots of the present disclosure can include various layers. For instance, in some embodiments, the carbon quantum dots of the present disclosure have a single layer. In some embodiments, the carbon quantum dots of the present disclosure have a plurality of layers. In some embodiments, the carbon quantum dots of the present disclosure have from about two layers to about four layers. [0055] The carbon quantum dots of the present disclosure can include various structures. For instance, in some embodiments, the carbon quantum dots of the present disclosure have a crystalline hexagonal structure.
- the carbon quantum dots of the present disclosure can also have various properties.
- the carbon quantum dots of the present disclosure are photoluminescent.
- the carbon quantum dots of the present disclosure emit light from the regions of the human visible spectrum.
- the carbon quantum dots of the present disclosure emit light from the blue-green (2.9 eV) to orange-red (2.05 eV) regions of the human visible spectrum.
- the carbon quantum dots of the present disclosure can also have various molecular weights.
- the carbon quantum dots of the present disclosure include molecular weights that range from about 20 kD to about 100 kD.
- the carbon quantum dots of the present disclosure include molecular weights that range from about 25 kD to about 75 kD.
- the carbon quantum dots of the present disclosure include molecular weights that range from about 40 kD to about 60 kD.
- the carbon quantum dots of the present disclosure have a molecular weight of about 60 kD.
- the carbon quantum dots of the present disclosure can also have various sizes. For instance, in some embodiments, the carbon quantum dots of the present disclosure include sizes that range from about 1 nm in diameter to about 200 nm in diameter. In some embodiments, the carbon quantum dots of the present disclosure include sizes that range from about 2 nm in diameter to about 80 nm in diameter. In some embodiments, the carbon quantum dots of the present disclosure include sizes that range from about 2 nm in diameter to about 65 nm in diameter.
- the carbon quantum dots of the present disclosure can also have various quantum yields. For instance, in some embodiments, the quantum yields of the carbon quantum dots are less than 1% and greater than 0.1%. In some embodiments, the quantum yields of the carbon quantum dots are between 1% and 10%. In some embodiments, the quantum yields of the carbon quantum dots can be as high 50%. In some embodiments, the quantum yields of the carbon quantum dots may be near 100%.
- the methods of the present disclosure can also include one or more steps of selecting a desired size of carbon quantum dots.
- the desired size includes a size range.
- the desired size includes a narrow size range.
- the desired size includes a plurality of sizes.
- the desired sizes of the carbon quantum dots include diameters that range from about 55 nm to about 85 nm, from about 45 nm to about 65 nm, from about 30 nm to about 50 nm, from about 20 nm to about 35 nm, from about 20 nm to about 30 nm, from about 10 nm to about 20 nm, from about 5 nm to about 10 nm, from about 2 nm to about 6 nm, from about 2 nm to about 4 nm, or from about 1 nm to about 3 nm.
- the present disclosure can utilize various methods to select a desired size of the formed carbon quantum dots.
- the selecting can include at least one of separating the desired size of the formed carbon quantum dots from other formed carbon quantum dots, selecting the reaction temperature that produces the desired size of the formed carbon quantum dots, and combinations of such steps.
- a desired size of carbon quantum dots is selected by selecting a reaction temperature that produces the desired size of the formed carbon quantum dots.
- the selected reaction temperature is a set temperature that remains constant during the exposing step.
- the selected reaction temperature is a temperature gradient. For instance, in some embodiments, the temperature gradient gradually increases during the exposing step. In some embodiments, the temperature gradient gradually decreases during the exposing step.
- the selected reaction temperature ranges from about 25 °C to about 200 °C. In some embodiments, the selected reaction temperature ranges from about 50 °C to about 150 °C. In some embodiments, the selected reaction temperature ranges from about 100 °C to about 150 °C.
- the desired size of the carbon quantum dots decreases as the selected reaction temperature increases. For instance, in some embodiments where the selected reaction temperature is about 50 °C, the selected reaction temperature produces carbon quantum dots with diameters that range from about 45 nm to about 65 nm. In some embodiments where the selected reaction temperature is about 110 °C, the selected reaction temperature produces carbon quantum dots with diameters that range from about 20 nm to about 35 nm. In some embodiments where the selected reaction temperature is about 130 °C, the selected reaction temperature produces carbon quantum dots with diameters that range from about 20 nm to about 30 nm. In some embodiments where the selected reaction temperature is about 150 °C, the selected reaction temperature produces carbon quantum dots with diameters that range from about 5 nm to about 10 nm.
- the functionalization level of carbon quantum dots increases as the selected reaction temperature increases. For instance, in some embodiments, carbon quantum dots become more oxidized as the reaction temperature increases. In some embodiments, the bandgap of the carbon quantum dots also increases as the selected reaction temperature increases.
- a desired size of carbon quantum dots is selected by separating the desired size of the formed carbon quantum dots from other formed carbon quantum dots. As set forth in more detail herein, various separation methods may be utilized. [0070] In some embodiments, the separation occurs by filtration. In some embodiments, the filtration includes, without limitation, macrofiltration, microfiltration, ultrafiltration, cross-flow filtration, cross-flow ultrafiltration, dialysis, membrane filtration, and combinations of such steps. In some embodiments, the filtration occurs by cross-flow filtration, such as cross-flow ultrafiltration.
- the filtration occurs through a porous membrane.
- the porous membrane includes pore sizes that range from about 1 kD to about 100 kD. In some embodiments, the pore sizes range from about 1 kD to about 50 kD. In some embodiments, the pore sizes range from about 3 kD to about 30 kD.
- the filtration occurs sequentially through multiple porous membranes. For instance, in some embodiments, a solution containing formed carbon quantum dots is filtered through a first porous membrane. The filtered solution is then filtered through second porous membrane. Thereafter, the filtered solution is filtered through a third porous membrane.
- the porous membranes that are utilized in sequential filtration steps have different pore sizes. In some embodiments, the porous membranes that are utilized in sequential filtration steps have sequentially increasing pore sizes.
- the first, second and third porous membranes have pore sizes of about 3 kD, 10 kD, and 30 kD, respectively.
- Filtration can occur under various conditions. For instance, in some embodiments, filtration occurs at transmembrane pressures that range from about 0.1 atmospheric pressure to about 10 atmospheric pressure. In some embodiments, filtration occurs at transmembrane pressures that range from about 0.5 atmospheric pressure to about 2 atmospheric pressure. In some embodiments, filtration occurs at about 1 atmospheric pressure.
- the methods of the present disclosure also include a step of purifying the formed carbon quantum dots (e.g., purification from oxidants in a solution).
- the purifying occurs prior to, during, or after a step of selecting the desired size of the formed carbon quantum dots.
- the purifying step includes, without limitation, extraction, filtration, evaporation, precipitation, dialysis, and combinations thereof.
- the purifying step includes neutralizing a solution that contains the formed carbon quantum dots, filtering the solution, and dialyzing the solution. In some embodiments, the purifying step includes dialyzing a solution that contains the formed carbon quantum dots. In some embodiments, the purifying step includes extracting the formed carbon quantum dots from a reaction mixture (e.g., a solution). In some embodiments, the extraction utilizes organic solvents, such as ethyl acetate or 2-butanol, or combinations of ethyl acetate and 2-butanol. Additional methods of purifying formed carbon quantum dots can also be envisioned.
- the methods of the present disclosure also include a step of enhancing the quantum yield of the formed carbon quantum dots.
- the enhancement step occurs prior to, during, or after a step of selecting the desired size of the formed carbon quantum dots.
- Various methods may be utilized to enhance the quantum yield of carbon quantum dots.
- Exemplary methods include, without limitation, hydrothermal treatment of the carbon quantum dots, treatment of the carbon quantum dots with one or more bases (e.g., sodium hydroxide), treatment of the carbon quantum dots with one or more hydroxides, treatment of the carbon quantum dots with one or more dopants (e.g., NaH 2 P0 3 ), treatment of the carbon quantum dots with one or more reducing agents, and combinations thereof.
- the enhancement of the quantum yield of carbon quantum dots occurs by hydrothermal treatment of the carbon quantum dots.
- the hydrothermal treatment includes treating the carbon quantum dots with hydroxide in water to increase their quantum yield.
- the hydrothermal treatment of the carbon quantum dots involves treating the carbon quantum dots with water under pressure in a container (e.g., a sealed vessel) at temperatures above 100 °C (e.g., temperatures of about 180 °C to 200 °C).
- the enhancement of the quantum yield of the carbon quantum dots occurs by treatment of the carbon quantum dots with one or more reducing agents.
- the reducing agents include, without limitation, hydrazine, sodium borohydride, heat, light, sulfur, sodium sulfide, sodium hydrogen sulfide, and combinations thereof.
- the enhancement step enhances the quantum yield of the carbon quantum dots by at least about 50%, at least about 100%, at least about 200%, or at least about 500%. In some embodiments, the enhancement step enhances the quantum yield of the carbon quantum dots by at least about 50%. In some embodiments, the enhancement step enhances the quantum yield of the carbon quantum from about 0.1% to about 50%.
- the methods of the present disclosure can be utilized to tune the bandgaps of the formed carbon quantum dots.
- the methods of the present disclosure can be utilized to produce carbon quantum dots with desired bandgaps.
- the bandgaps of the carbon quantum dots range from about 0.5 eV to about 5 eV.
- the bandgaps of the carbon quantum dots range from about 1 eV to about 5 eV.
- the bandgaps of the carbon quantum dots range from about 1 eV to about 5 eV.
- the bandgaps of the carbon quantum dots range from about 0.5 eV to about 3 eV.
- the bandgaps of the carbon quantum dots range from about 1 eV to about 3 eV. In some embodiments, the bandgaps of the carbon quantum dots range from about 2 eV to about 3 eV. In some embodiments, the bandgaps of the carbon quantum dots are less than about 1.5 eV. In some embodiments, the bandgaps of the carbon quantum dots are less than about 3 eV.
- the methods of the present disclosure can be utilized to form carbon quantum dots with desired bandgaps in a scalable manner.
- the methods of the present disclosure can form carbon quantum dots in bulk quantities.
- the bulk quantities range from about 1 g of carbon quantum dots to about 10 tons of carbon quantum dots.
- the bulk quantities are more than about 1 g of carbon quantum dots.
- the bulk quantities are more than about 500 g of carbon quantum dots.
- the bulk quantities are more than about 1 kg of carbon quantum dots.
- GQDs photoluminescent graphene quantum dots
- GQDs were synthesized with tailored sizes and bandgaps.
- the GQDs emit light from blue-green (2.9 eV) to orange -red (2.05 eV), depending on size, functionalities and defects.
- the GQDs were rapidly purified using cross-flow ultrafiltration to separate them by size via variation of the membrane pore size.
- cross-flow ultrafiltration is used in very large-scale industrial processes for industrial and municipal water purification and for food separations.
- the emission wavelengths of the purified GQDs depend on their sizes, in accordance with the quantum confinement effect, and on their functionalities and defects.
- raw anthracite is first dispersed in a mixed solvent of sulfuric acid and nitric acid, and then heated at a defined temperature for 24 hours, which results in a clear solution.
- the GQD solution was processed with a cross-flow system (FIG. 2B) using sequentially 3 kD, 10 kD and 30 kD pore size membranes at ⁇ 1 atm transmembrane pressure (TMP).
- FIGS. 2C-F show the transmission electron microscopy (TEM) images of the as- separated GQDs and their corresponding sizes.
- TEM transmission electron microscopy
- DLS dynamic light scattering
- the size distribution in FIG. 2G is statistically averaged from the TEM images with a sample size of ⁇ 150 particles.
- the distribution of hydrodynamic diameters was calculated from the light scattering in bulk solution. After the purification process, TEM images reveal that GQDs with average sizes of 4.5 + 1.2, 16 + 3.3, 41 + 6.4 and 70 + 15 nm were obtained. The corresponding hydrodynamic diameters were 10 + 2.5, 27 + 7.9, 41 + 11 and 76 + 18 nm, respectively.
- the enlarged size in the DLS analyses was attributed to the hydration layers around the GQDs.
- the corresponding GQD batches are denoted as GQDs-Sx, where "S” signifies "separated” and "x" indicates the average diameter from TEM images.
- GQDs were further confirmed by X-ray photoelectron spectroscopy (XPS) analyses and Fourier transform infrared (FTIR) analyses.
- XPS X-ray photoelectron spectroscopy
- FTIR Fourier transform infrared
- FIGS. 5B-E the high resolution Cls XPS spectra of GQDs show the presence of COOH and C-0 peaks at 288.8 eV and 286.6 eV, respectively.
- FIG. 5F The relative abundances of these functionalities are summarized in FIG. 5F.
- the quantitative assessment of relative aromatic/alkene to carbonyl ratios is not as descriptive as in the NMR experiments.
- FIG. 7 shows the UV-visible absorption of the GQDs. Larger GQDs tend to absorb at longer wavelengths, while the absorption of smaller GQDs is blue-shifted. The broad absorption of larger GQDs is attributed to the complexity of the electronic states.
- FIGS. 8A-E show the 2-D excitation-emission contour maps of the GQDs. Under a 365 nm UV light, these quantum dots solutions emit light across the majority of the visible spectrum from green ( ⁇ 2.4 eV) to orange-red ( ⁇ 1.9 eV) regions (FIG. 8F). The correlations between bandgap and size or molecular weight cut-off are summarized in FIG. 8G. As expected, when the GQDs size increases from 4.5 nm to 70 nm, the peak emission is red-shifted from ⁇ 520 nm to ⁇ 620 nm, which is in accordance with the quantum confinement effect. These GQDs exhibit different fluorescent quantum yields of 1.1%, 0.89%, 0.65% and 0.38% using quinine sulfate as reference standard, as the GQDs size increases from 4.5 nm to 70 nm.
- the separation technique can efficiently produce GQDs with controlled sizes.
- the relative yields of GQDs-S4.5, GQDs-S16, GQDs-S41 and GQDs-S70 were 8%, 30%, 52% and 10%, respectively. This represents a 1.6%, 6%, 10% and 2% yield by weight starting from anthracite. Therefore, the overall yield of GQDs is about 20%.
- the second method used to tailor the size of the GQDs samples was through direct synthesis techniques rather than separation.
- This facile method for the production of size- differentiated GQDs, in one step without cross-flow ultrafiltration, is based on control of the reaction temperature.
- the GQDs synthesized at different temperatures for 24 hours are denoted as GQDs-Tx-y, where "T” signifies “temperature”, “x” indicates the synthesis temperature, and "y” signifies the TEM-derived size.
- T signifies "temperature”
- x indicates the synthesis temperature
- y signifies the TEM-derived size.
- the higher temperature produces more oxidation and etches the GQDs into smaller sizes, leading to an enlarged bandgap.
- the change in GQD size is shown in the TEM images (FIG.
- the high resolution Cls XPS spectra show that the percentage of COOH functionality increases from ⁇ 4% to ⁇ 22% while the C-C bond content decreases from ⁇ 93% to ⁇ 65% as the synthesis temperature was increased from 50 °C to 150 °C.
- the corresponding changes in the NMR spectra stronger signal near 170 ppm and reduced aromatic/alkene intensity
- the non- carboxyl C-0 content remained constant throughout the temperature range.
- Applicants further examined the UV-visible absorption and 2D excitation-emission of GQDs synthesized at the different temperatures.
- the absorption spectra of GQDs synthesized at different temperatures are similar to the spectra of the GQDs prepared by cross-flow ultrafiltration. At higher synthesis temperatures, the absorption curve slopes were in the low wavelength region. At the low synthesis temperatures, the absorption tends to be broad across the visible region.
- Applicants further studied the control of the GQD bandgap through reaction temperature by analyzing the emission properties of GQDs. As shown in FIGS. 16A-E, the emission peak shifts from ⁇ 580 nm to ⁇ 420 nm as the temperature elevates from 50 °C to 150 °C, corresponding to the orange-red and blue-green emission color, respectively. The maximum excitation also shifts from ⁇ 320 nm to ⁇ 300 nm as the temperature decreases from 150 °C to 50 °C. This red-shift in maximum excitation is attributed to the narrowing of the bandgap at lower synthesis temperatures. The change in bandgap is visualized in FIG.
- the COOH content increases and the C-C content decreases at higher temperature.
- the tunable bandgap of GQDs can be attributed to both the size effect and functionality effect.
- GQDs extracted from bituminous coal at 120 °C emit blue light under a 365 nm UV lamp.
- Anthracite (Fisher Scientific, catalogue number S98806), bituminous coal (Fisher Scientific, catalogue number S98809), graphite (Sigma- Aldrich, catalogue number 332461, B 150mm flakes), H 2 S0 4 (95-98%, Sigma- Aldrich), and HN0 3 (70%, Sigma- Aldrich) were used as received unless noted otherwise.
- Polytetrafluoroethylene membranes (Sartorius, lot number 11806-47-N) and dialysis bags (Membrane Filtration Products, Inc. Product number 1-0150-45) were used to purify the GQDs.
- the cross-flow ultrafiltration instrument was a Spectrum Labs Ksosflo, Research Hi TFF System.
- the ultra-filtration membranes were hollow membranes made of modified polyethersulfone.
- the ultra-filtration membranes were also purchased from Spectrum Lab (Product number D02-Exxx-05-S).
- Example 1.3 Separation of GQDs by cross-flow ultrafiltration
- the as-prepared GQDs are separated using cross-flow ultrafiltration. Ultra-filtration occurs sequentially through three different membranes with pore sizes of 3 kilo Dalton (kD), 10 Kd and 30 kD, respectively.
- the transmembrane pressure (TMP) of the membranes was at ⁇ 1 atm.
- the flow rate was kept constant throughout the experiment at about ⁇ 50-100 mL/minute.
- Example 1.4 Preparation of GQDs at varying temperatures
- 3 g of anthracite was dispersed in a mixed solvent of 225 mL sulfuric acid and 75 mL nitric acid.
- the solution was sonicated (Cole Parmer, model 08849-00) for 2 hours and then heated at different temperatures (50 to 150 °C) for 1 day. After the thermal oxidation, a clear brown-red solution resulted.
- the solution was then cooled in an ice-water bath and diluted three times with DI water. After that, the solution was dialyzed in a 1000 Dalton dialysis bag against DI water for 3 days.
- a 15 mL aqueous solution containing 1 mg/mL GQDs in 1 M Na 2 S was prepared in a round-bottom flask. The solution was heated to 100 °C under nitrogen for 1 day. After cooling to room temperature, the solution was transferred to a 1000 Dalton dialysis bag and was dialyzed against DI water for 3 days.
- TEM images were taken using a 2100 F field emission gun TEM with GQDs directly transferred onto a C-flat TEM grid. Dynamic light scattering was performed on a Malvern Zen 3600 Zetasizer with refractive index of 2 at 25 °C. X-ray photoelectron spectroscopy (XPS) spectra were measured on a PHI Quantera SXM scanning X-ray microprobe with a 45° take-off angle and 100 ⁇ beam size. The pass energy for surveys was 140 and 26 eV for high-resolution scans. A 2 nm Au layer was sputtered (Denton Desk V Sputter system) on the sample surface before scanning.
- XPS X-ray photoelectron spectroscopy
- Direct C pulse spectra were obtained with 12 kHz MAS, a 90° pulse, 20.5 ms FID, 10 s relaxation delay, and differing number of scans (1440 for GQDs-S4.5, 1600 for GQDs- S 16, 3400 for GQDs-S41, 3280 for GQDs-S70, 9024 for GQDs-T150-7.6, 16928 for GQDs- T130-25, 8096 for GQDs-Tl 10-27 and 6328 for GQDs-T50-54), with each FID processed with
- H- C CP spectra were obtained with 7.6 kHz MAS, a 1 ms contact time, 32.8 ms FID, 5 s relaxation delay, and differing number of scans (10600 for each of GQDs-S4.5, GQDs-S41, GQDs-S70 and 10400 for GQDs-S 16, 30632 for GQDs-T150-7.6, 32600 for GQDs-T130-25, 14000 for GQDs-Tl 10-27, and 17000 for GQDs-T50-54), with each FID processed with 50 Hz of line broadening. More scans were taken for GQDs-Tl 50-7.6 and GQDs-T130-25 to compensate for the limited amount of sample available.
- Pp , PR, and Pp are the pressure at feed, retentate and permeate, respectively.
- the TMP value used in the cross-flow filtration was kept constant at ⁇ 1 atm.
- ⁇ P r are the quantum yield of samples and reference, respectively.
- the integrated intensities (area) of sample and reference are Ij and I r , respectively.
- Ai and A r are the absorbance, 3 ⁇ 4 and n r are the refractive indices of the samples and reference solution, respectively.
- Example 2 Alternative Methods of Making Graphene Quantum Dots
- This example provides additional methods by which graphene quantum dots could be synthesized. This includes the use of nitric acid only. It also includes the use of removal of the nitric acid by evaporation after the reaction is complete. It also includes the extraction of the GQDs from the acid solution using ethyl acetate or ethyl acetate/2-butanol mixtures, and then evaporation of the organic solvents.
- the reaction mixture was then filtered through a sinter to remove a black solid.
- 150 mL of filtrate was extracted with 150 mL of 2-butanol/ethyl acetate (v/v, 60/40).
- the organic layer was dried by MgS0 4 and filtered through a sinter.
- the solution was concentrated using rotary evaporation to obtain solid GQDs.
- the GQD solid was dried at 60 °C in a vacuum oven for 15 hours.
- the GQD solid (21% yield) was partially soluble in water. Size selection can be conducted as described previously by crossflow filtration.
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040223901A1 (en) * | 1998-11-03 | 2004-11-11 | William Marsh Rice University | Single-wall carbon nanotubes from high pressure CO |
CN101973541A (en) * | 2010-10-11 | 2011-02-16 | 福州大学 | Method for extracting carbon quantum dots from activated carbon |
US20110217721A1 (en) * | 2010-03-08 | 2011-09-08 | Afreen Allam | Water soluble fluorescent quantum carbon dots |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7842271B2 (en) * | 2004-12-07 | 2010-11-30 | Petrik Viktor I | Mass production of carbon nanostructures |
CN102604629A (en) * | 2012-02-08 | 2012-07-25 | 中国人民解放军军事医学科学院卫生装备研究所 | Preparation method and applications of amino carbon quantum dots |
CN102849724B (en) * | 2012-10-12 | 2014-08-20 | 上海交通大学 | Preparation method of water-soluble carbon quantum dots |
-
2015
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-
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040223901A1 (en) * | 1998-11-03 | 2004-11-11 | William Marsh Rice University | Single-wall carbon nanotubes from high pressure CO |
US20110217721A1 (en) * | 2010-03-08 | 2011-09-08 | Afreen Allam | Water soluble fluorescent quantum carbon dots |
CN101973541A (en) * | 2010-10-11 | 2011-02-16 | 福州大学 | Method for extracting carbon quantum dots from activated carbon |
Non-Patent Citations (3)
Title |
---|
PAN ET AL.: "Hydrothermal route for cutting graphene sheets into blue-luminescent graphene quantum dots", ADVANCED MATERIALS, vol. 22, no. 6, 9 February 2010 (2010-02-09), pages 734 - 738, XP055081297 * |
See also references of EP3157868A4 * |
YE ET AL.: "Coal as an abundant source of graphene quantum dots", NATURE COMMUNICATIONS, vol. 4, 6 December 2013 (2013-12-06), XP055285529 * |
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