Fluorescent solar light collector and preparation method thereof

Abstract

The invention provides a fluorescent solar light collector based on CuInS2 / ZnS semiconductor quantum dots and a preparation method of the fluorescent solar light collector. The structure is a double-interlayer structure, yellow, orange and red CuInS2 / ZnS quantum dots are used as luminescent materials, and an acrylate polymer is used as a waveguide material. The preparation method comprises the following steps: (1) synthesizing yellow, orange and red CuInS2 / ZnS quantum dots by a one-pot method; (2) mixing a certain amount of yellow, orange and red quantum dots with a polymer monomer, and obtaining a suspension of the quantum dots / polymer monomer after the solvent is evaporated; adding a certain amount of photoinitiator and cross-linking agent into the suspension, and uniformly oscillating; and clamping the suspension containing the orange or red CuInS2 / ZnS quantum dots between optical glass sheets, and carrying out photopolymerization under an ultraviolet lamp to obtain the single-interlayer fluorescent solar light collector with the orange or red CuInS2 / ZnS quantum dots after the polymerization is completed. A certain amount of the yellow or orange CuInS2 / ZnS quantum dot suspension liquid is dropped on the single-interlayer fluorescent solar light collector, another optical glass sheet covers the single-interlayer fluorescent solar light collector, and the single-interlayer fluorescent solar light collector is obtained through polymerization under ultraviolet light. The fluorescent solar light collector prepared by the invention is simple in preparation method, low in toxicity, low in cost, good in stability and high in optical efficiency.

Description

Technical Field

[0001] This invention relates to a double-sandwich fluorescent solar collector based on CuInS2 / ZnS semiconductor quantum dots and its fabrication method, particularly to the application of this photovoltaic device in building-integrated photovoltaics (BIPV) systems such as photovoltaic glass and photovoltaic roofs. Background Technology

[0002] With rapid global population growth and continuously improving living standards, humanity's demand for energy is increasing daily. However, the over-exploitation of fossil fuels has already begun to reveal an energy crisis. Therefore, actively seeking new clean and renewable energy sources is urgent to alleviate energy shortages and mitigate environmental degradation. Solar energy, as an inexhaustible and clean energy source, has attracted widespread attention. Currently, the utilization of solar energy mainly relies on crystalline silicon solar cells, but silicon solar cells have high costs and low photoelectric conversion efficiency when used over large areas. Fluorescent solar collectors offer a reliable solution to these problems.

[0003] A fluorescent solar concentrator (LSC) is a photoelectric device used to collect, convert, transmit, and concentrate sunlight. A LSC consists of a transparent waveguide coated or embedded with various types of luminescent materials. When sunlight shines on the upper surface of the LSC, the fluorescent material absorbs the incident light and emits fluorescence again through photoluminescence. The energy of the re-emitted fluorescence is lower than that of the incident light (i.e., a redshift). This fluorescence is isotropically transmitted into the optical waveguide. When the fluorescence is incident on the upper and lower surfaces of the waveguide, fluorescence with an incident angle smaller than the total internal reflection angle escapes; while fluorescence with an incident angle greater than the total internal reflection angle is confined within the optical waveguide by total internal reflection and transmitted to the edge-connected solar cells, thus achieving photoelectric conversion. Based on the working principle of the LSC, researchers have proposed its application in building-integrated photovoltaics (BIPV) technology. It can be installed in transparent parts of buildings, such as window glass, allowing photovoltaic devices coupled to the sides to directly power the building. Compared with traditional physical light-collecting devices, applying LSCs to buildings has many advantages: (1) It can absorb incident light from multiple angles, and can collect both direct sunlight on sunny days and scattered sunlight on cloudy days, so its performance is almost unaffected by weather factors; (2) It reduces weight, and the weight of thin-film LSCs can be negligible, making it easy to install on the side of buildings; (3) It avoids direct sunlight and reduces the thermal effect of the device; (4) The cost is much lower than that of solar cells. Replacing large-area solar cells with LSCs can effectively reduce costs; (5) The shape, color, etc. can be adjusted, and its application to buildings will not affect lighting. It can even develop multifunctional thin films.

[0004] Improving the photoelectric conversion efficiency of LSCs remains a major challenge, with fluorescent materials and the LSC structure being the main factors influencing their photoelectric performance. Highly efficient fluorescent materials should possess high fluorescence quantum yield, large Stokes shift, good stability, and long emission wavelength. Currently, traditional semiconductor quantum dots suffer from drawbacks such as high toxicity and high cost. However, I-III-VI type CuInS2 / ZnS semiconductor quantum dots offer advantages such as high fluorescence quantum yield, large Stokes shift, good stability, low toxicity, low cost, and tunable emission wavelength, making them a good choice for LSC fluorescent materials. On the other hand, traditional single-segment LSCs have low fluorescence efficiency and are easily affected by external oxygen and moisture, resulting in poor long-term stability and hindering their practical application in photovoltaic glass. The double-layer structure design, however, improves the utilization efficiency of sunlight through the stepwise absorption and emission of light between different layers, achieving a simultaneous improvement in both LSC efficiency and stability. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a double-sandwich fluorescent solar collector based on CuInS2 / ZnS semiconductor quantum dots and its fabrication method. The aim is to introduce CuInS2 / ZnS semiconductor quantum dots into the fluorescent solar collector, utilizing the absorption and emission of quantum dots at different layers to improve the efficiency of the fluorescent solar collector. Furthermore, the double-sandwich structure of this fluorescent solar collector protects the fluorescent quantum dots, improving the long-term stability of the device. Compared with traditional fluorescent solar collectors, this fluorescent solar collector has advantages such as better stability and higher light collection efficiency.

[0006] To achieve the above objectives, the specific technical solution of this invention is a double-sandwich fluorescent solar collector based on CuInS2 / ZnS semiconductor quantum dots and its preparation method.

[0007] The preparation method includes the following steps:

[0008] (1) Preparation of CuInS2 / ZnS quantum dots: A certain amount of indium acetate and cuprous iodide were added to n-dodecyl mercaptan and mixed and heated under a nitrogen atmosphere to remove water and oxygen. The mixture was then heated to a certain temperature and held for a certain time to obtain CuInS2 quantum dots. After cooling, a mixture of zinc chloride and n-dodecyl mercaptan was continuously added to obtain CuInS2 / ZnS quantum dots. The mixture was then cooled to room temperature and centrifuged with ethanol to obtain the final product.

[0009] (2) Preparation of a double-sandwich fluorescent solar collector: A certain amount of yellow, orange, and red quantum dots are mixed with polymer monomers, and after the solvent evaporates, a quantum dot / polymer monomer suspension is obtained. A certain amount of photoinitiator and crosslinking agent are then added to the suspension and shaken evenly. Subsequently, the above suspension containing orange or red CuInS2 / ZnS quantum dots is sandwiched between optical glass plates and photopolymerized under ultraviolet light. After polymerization, a single-sandwich fluorescent solar collector with orange or red CuInS2 / ZnS quantum dots is obtained. Then, a certain amount of the above yellow or orange CuInS2 / ZnS quantum dot suspension is dropped onto the above single-sandwich fluorescent solar collector and covered with another optical glass plate. Polymerization is then carried out under ultraviolet light to obtain the final product.

[0010] In the above preparation method, in step (1), the molar ratio of indium acetate to cuprous iodide is 1:12, 1:8 and 1:4, respectively, to obtain yellow, orange and red CuInS2 / ZnS quantum dots.

[0011] In the above preparation method, in step (1), the temperature for dehydration and deoxygenation is 80-100 ℃ and the time is 30-60 min.

[0012] In the above preparation method, in step (1), the temperature for synthesizing CuInS2 quantum dots is 200-230℃ and the reaction time is 5-30 min.

[0013] In the above preparation method, in step (1), the temperature after cooling is 180-210 ℃.

[0014] In the above preparation method, in step (1), the concentration of zinc chloride added is 1 mmol / mL.

[0015] In the above preparation method, in step (2), the mass fraction of quantum dots in the suspension is 0.5-2%.

[0016] In the above preparation method, in step (2), the evaporation temperature is 60-100 ℃.

[0017] In the above preparation method, the evaporation time in step (2) is 6-24 h.

[0018] In the above preparation method, in step (2), the amount of suspension used is 120 μL-2.4 mL.

[0019] In the above preparation method, in step (2), the photopolymerization time is 2-10 min.

[0020] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0021] (1) The present invention uses CuInS2 / ZnS quantum dots as the fluorescent layer to prepare a solar collector. The preparation method is simple and the cost is low.

[0022] (2) Compared with traditional fluorescent solar collectors, this invention introduces CuInS2 / ZnS quantum dots into the solar collector and utilizes the absorption and emission of quantum dot fluorescent layers between different levels to improve the efficiency of the fluorescent solar collector.

[0023] (3) The fluorescent solar collector adopts a double-sandwich structure, which can protect the quantum dot fluorescent layer and improve the long-term stability of the device.

[0024] In summary, compared with the prior art, the above-mentioned technical solutions conceived in this invention can achieve advantages such as simple preparation, low synthesis cost, high optical efficiency, and good stability.

[0025] Instruction manual illustrations

[0026] Figure 1: Schematic diagram of a double-layer fluorescent solar collector.

[0027] Figure 2: HRTEM images of yellow, orange and red CuInS2 / ZnS quantum dots.

[0028] Figure 3: Optical images of yellow, orange, and red CuInS2 / ZnS quantum dot toluene solutions under ambient light (ac) and ultraviolet light (df).

[0029] Figure 4: Optical images of a single-sandwich fluorescent solar collector containing yellow, orange, and red CuInS2 / ZnS quantum dots under ambient light (ac) and ultraviolet light (df).

[0030] Figure 5: Optical images of a double-sandwich fluorescent solar collector containing yellow, orange, and red CuInS2 / ZnS quantum dots under ambient light (ac) and ultraviolet light (df).

[0031] Figure 6: JV characteristic curves (a) and performance bar charts (b) of a double-sandwich fluorescent solar collector containing yellow, orange and red CuInS2 / ZnS quantum dots.

[0032] Specific Implementation Cases

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0034] Example 1

[0035] The preparation of yellow, orange, and red CuInS2 / ZnS quantum dots includes the following steps:

[0036] (1) Yellow CuInS2 / ZnS quantum dots were prepared by a one-pot method. Figure 3 (a, d). The steps are as follows: 0.1022 g ZnCl2 and 0.75 mL n-dodecyl mercaptan were mixed at room temperature and sonicated until a transparent solution was formed to prepare the zinc precursor solution. The concentration of the zinc precursor solution was 1 mmol / mL. 0.1752 g indium acetate and 0.0095 g cuprous iodide were placed in a 25 mL three-necked flask, and 5 mL n-dodecyl mercaptan was added. While stirring vigorously, the mixture was degassed under vacuum for 10 minutes, and then purged with N2. This process was repeated three times. Afterward, the mixture was kept under vacuum at 80 °C for 30 minutes to remove moisture and oxygen, and then the temperature was increased to 210 °C and kept under N2 atmosphere for 20 minutes. After cooling to 200 °C, the zinc precursor solution was added dropwise to the core solution using a syringe (1 mL / 30 min). After the zinc precursor solution was completely injected, the heat source was removed to stop the reaction. After the solution cooled to room temperature, excess ethanol was added and the mixture was centrifuged three times. The supernatant was then removed and the precipitate was dissolved in toluene. The synthesized quantum dots are quasi-spherical with lattice fringes of 0.32 nm, such as... Figure 2 As shown in (a).

[0037] (2) Preparation of orange CuInS2 / ZnS quantum dots by a one-pot method Figure 3 (b, e). Step 1: Mix 0.1022 g ZnCl2 with 0.75 mL n-dodecyl mercaptan at room temperature and sonicate until a clear solution is formed to prepare the zinc precursor solution. The concentration of the zinc precursor solution is 1 mmol / mL. Take 0.1168 g indium acetate and 0.0095 g cuprous iodide into a 25 mL three-necked flask, add 5 mL n-dodecyl mercaptan, stir vigorously, and degas under vacuum for 10 minutes. Then purge with N2, repeating three times. Afterward, maintain at 80 °C under vacuum for 30 minutes to remove moisture and oxygen, then raise the temperature to 225 °C and maintain under N2 atmosphere for 15 minutes. Then cool to 200 °C, and add the zinc precursor solution dropwise into the core solution using a syringe (1 mL / 30 min). After the zinc precursor solution is completely injected, remove the heat source to stop the reaction. After the solution cools to room temperature, add excess ethanol and centrifuge three times. Then remove the supernatant and dissolve the precipitate in toluene. The synthesized quantum dots are quasi-spherical with lattice fringes of 0.32 nm, such as... Figure 2 As shown in (b).

[0038] (3) Preparation of red CuInS2 / ZnS quantum dots by a one-pot method Figure 3(c, f). The steps are as follows: 0.1022 g ZnCl2 and 0.75 mL n-dodecyl mercaptan were mixed at room temperature and sonicated until a transparent solution was formed to prepare the zinc precursor solution. The concentration of the zinc precursor solution was 1 mmol / mL. 0.0584 g indium acetate and 0.0095 g cuprous iodide were placed in a 25 mL three-necked flask, and 5 mL n-dodecyl mercaptan was added. While stirring vigorously, the mixture was degassed under vacuum for 10 minutes, and then purged with N2. This process was repeated three times. Afterward, the mixture was kept under vacuum at 80 °C for 30 minutes to remove moisture and oxygen, and then the temperature was increased to 230 °C and kept under N2 atmosphere for 10 minutes. After cooling to 200 °C, the zinc precursor solution was added dropwise to the core solution using a syringe (1 mL / 30 min). After the zinc precursor solution was completely injected, the heat source was removed to stop the reaction. After the solution cooled to room temperature, excess ethanol was added and the mixture was centrifuged three times. The supernatant was then removed and the precipitate was dissolved in toluene. The synthesized quantum dots are quasi-spherical with lattice fringes of 0.32 nm, such as... Figure 2 As shown in (c).

[0039] Example 2

[0040] The fabrication and application of a double-sandwich fluorescent solar collector containing yellow and orange CuInS2 / ZnS quantum dots includes the following steps:

[0041] (1) 1 mL of orange CuInS2 / ZnS quantum dot solution dissolved in toluene was added to 1 mL of hydroxyethyl methacrylate monomer, and then evaporated at 60 °C for 12 h to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the suspension, and the mixture was shaken to mix. 150 μL of the suspension was dropped onto a transparent glass slide, and another glass slide of the same size was placed on top. Photopolymerization was then performed under ultraviolet light to prepare a single-sandwich fluorescent solar collector containing orange CuInS2 / ZnS quantum dots. Optical photographs of the single-sandwich fluorescent solar collector containing orange CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown below. Figure 4 As shown in (b, e).

[0042] (2) 1 mL of a yellow CuInS2 / ZnS quantum dot solution dissolved in toluene was added to 1 mL of hydroxyethyl methacrylate monomer, and then evaporated at 60 °C for 12 h to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the suspension, and the mixture was shaken to mix. 150 μL of the suspension was dropped onto a transparent glass slide, and another glass slide of the same size was placed on top. Photopolymerization was then performed under ultraviolet light to prepare a double-sandwich fluorescent solar collector containing yellow and orange CuInS2 / ZnS quantum dots. Optical photographs of a single-sandwich fluorescent solar collector containing yellow CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown below. Figure 4 As shown in (a, d), optical photographs of a double-sandwich fluorescent solar collector containing yellow and orange CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown. Figure 5 As shown in (a, d), the external optical efficiency of this double-sandwich fluorescent solar collector reaches 5.09%, as... Figure 6 As shown.

[0043] Example 3

[0044] The fabrication and application of a double-sandwich fluorescent solar collector containing yellow and red CuInS2 / ZnS quantum dots includes the following steps:

[0045] (3) 1 mL of a red CuInS2 / ZnS quantum dot solution dissolved in toluene was added to 1 mL of hydroxyethyl methacrylate monomer, and then evaporated at 60 °C for 12 h to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the suspension, and the mixture was shaken to mix. 150 μL of the suspension was dropped onto a transparent glass slide, and another glass slide of the same size was placed on top. Photopolymerization was then performed under ultraviolet light to prepare a single-sandwich fluorescent solar collector containing red CuInS2 / ZnS quantum dots. Optical photographs of the single-sandwich fluorescent solar collector containing red CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown below. Figure 4 As shown in (c, f).

[0046] (4) 1 mL of a yellow CuInS2 / ZnS quantum dot solution dissolved in toluene was evaporated at 60 °C for 12 h. Then, 1 mL of hydroxyethyl methacrylate monomer was added, and the mixture was shaken thoroughly to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the suspension, and the mixture was shaken thoroughly. 150 μL of the suspension was dropped onto a transparent glass slide, and another glass slide of the same size was placed on top. Photopolymerization was then performed under ultraviolet light to prepare a double-sandwich fluorescent solar collector containing yellow and red CuInS2 / ZnS quantum dots. Optical photographs of the double-sandwich fluorescent solar collector containing yellow and red CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown below. Figure 5 As shown in (b, e), the external optical efficiency of this double-sandwich fluorescent solar collector reaches 5.27%, as... Figure 6 As shown.

[0047] Example 4

[0048] The fabrication and application of a double-sandwich fluorescent solar collector containing orange and red CuInS2 / ZnS quantum dots includes the following steps:

[0049] (5) 1 mL of red CuInS2 / ZnS quantum dot solution dissolved in toluene was added to 1 mL of hydroxyethyl methacrylate monomer, and then evaporated at 60 °C for 12 h to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the above suspension, shaken to mix, and 150 μL of the suspension was dropped onto a transparent glass slide, and then another glass slide of the same size was placed on top. Subsequently, photopolymerization was carried out under ultraviolet light to prepare a single-sandwich fluorescent solar collector containing red CuInS2 / ZnS quantum dots.

[0050] (6) One mL of orange CuInS2 / ZnS quantum dot solution dissolved in toluene was evaporated at 60 °C for 12 h. Then, one mL of hydroxyethyl methacrylate monomer was added, and the mixture was shaken thoroughly to prepare a quantum dot-hydroxyethyl methacrylate suspension with a quantum dot content of 2 wt%. Subsequently, 0.05 mL of photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone and 0.05 mL of crosslinking agent ethylene glycol dimethacrylate were added to the suspension, and the mixture was shaken thoroughly. 150 μL of the suspension was dropped onto a transparent glass slide, and another glass slide of the same size was placed on top. Photopolymerization was then performed under ultraviolet light to prepare a double-sandwich fluorescent solar collector containing orange and red CuInS2 / ZnS quantum dots. Optical photographs of the double-sandwich fluorescent solar collector containing red and orange CuInS2 / ZnS quantum dots under ambient light and ultraviolet light are shown below. Figure 5 As shown in (c, f), the external optical efficiency of this double-sandwich fluorescent solar collector reaches 7.15%, as... Figure 6 As shown.

Claims

1. This invention provides a double-sandwich type fluorescent solar collector, characterized in that: Using CuInS2 / ZnS semiconductor quantum dots as the light-emitting material and acrylate polymers as the waveguide material, its structural feature is a double-sandwich structure, which consists of a single sandwich layer containing yellow or orange CuInS2 / ZnS quantum dots and a single sandwich layer containing orange or red CuInS2 / ZnS quantum dots.

2. This invention provides a method for fabricating a double-sandwich fluorescent solar collector based on CuInS2 / ZnS quantum dots, comprising the following steps: (1) Preparation of CuInS2 / ZnS semiconductor quantum dots: A certain amount of indium acetate and cuprous iodide were added to a certain amount of n-dodecyl mercaptan and heated under a nitrogen atmosphere to obtain CuInS2 quantum dots. After cooling to a certain temperature, a certain amount of a mixture of zinc chloride and n-dodecyl mercaptan was continuously added dropwise. After a period of time, the mixture was cooled to room temperature and centrifuged to obtain CuInS2 / ZnS semiconductor quantum dots. By controlling the ratio of indium acetate to cuprous iodide added in the above reaction, yellow, orange or red CuInS2 / ZnS quantum dots were obtained. (2) Preparation of double-layer fluorescent solar collector: First, yellow, orange or red CuInS2 / ZnS quantum dots dissolved in toluene are added to an acrylate polymer. Then, the solvent is evaporated at 60-100℃ to obtain a quantum dot / polymer monomer suspension. Subsequently, 5-10wt% of photoinitiator and crosslinking agent are added to the above suspension and shaken to mix. Then, a certain amount of orange or red CuInS2 / ZnS quantum dot suspension is dropped onto a transparent glass, and then covered with another transparent glass of the same size. Photopolymerization is carried out under ultraviolet light for 5-10 min to produce a single-layer fluorescent solar collector containing orange or red CuInS2 / ZnS quantum dots. Finally, a certain amount of suspension containing yellow or orange CuInS2 / ZnS quantum dots is dropped onto the above single-layer glass plate, and then covered with another transparent glass plate of the same size. Photopolymerization is carried out under ultraviolet light for 5-10 minutes to produce a double-layer fluorescent solar collector containing yellow, orange or red CuInS2 / ZnS quantum dots.

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