Use of essential oil in manufacturing solar cells, a manufacturing method and manufactured solar cells

Abstract

This invention provides a use of essential oils in the manufacture of solar cells, specifically as an electrode material. The manufacturing process involves first mixing the essential oil with titanium dioxide using a surfactant to prepare a first electrode material. This first electrode material is then coated onto a first conductive glass substrate and baked to form a first electrode material layer, which comprises a mixture of essential oil, surfactant, and titanium dioxide. Next, a second electrode material layer is formed on a second conductive glass substrate, and finally, an electrolyte is injected between the first and second electrode material layers. The solar cell of this invention exhibits high photoelectric conversion efficiency and is suitable for indoor environments.

Description

Technical Field

[0001] This invention relates to the use of an essential oil, and more particularly to the use of an essential oil in the manufacture of solar cells. Prior Technology

[0002] Essential oils are aromatic substances, generally aromatic molecules extracted from plants. They are mostly composed of terpenes and are organic compounds produced through photosynthesis. They are highly hydrophobic and are important products in the perfume, flavoring, and cosmetic industries, as well as a major ingredient in aromatherapy. They may also be used to repel pests. However, studies have shown that some essential oils have photosensitive reactions, also known as phototoxic reactions. This refers to the allergic reaction that occurs when skin comes into contact with photosensitive essential oils and is then exposed to sunlight or artificial light.

[0003] While some of these photosensitive essential oils should be kept away from light for a period of time after use, and some are not suitable for the aforementioned common uses, photosensitivity also means that these essential oils have a strong ability to absorb light. Therefore, using essential oils as electrode materials for solar cells may be suitable.

[0004] Conventional sensitized solar cell fabrication techniques typically use dyes as the photosensitizer. Unlike essential oils, dyes are usually water-soluble, while essential oils have poor hydrophilicity. Dye-sensitized solar cells (DSSCs) have attracted considerable attention due to their simple fabrication and low cost. Compared to traditional silicon-based or thin-film solar cells, DSSCs possess many unique advantages. DSSCs can operate under low light intensity conditions, even in indoor environments, and can effectively convert energy, thus exhibiting superior performance compared to other solar cells.

[0005] However, since the introduction of dye-sensitized solar cells in 1991, research in academia and industry has largely focused on improving conversion efficiency and extending lifespan, without developing alternative photosensitive materials. Essential oils, due to their different composition and hydrophobic properties compared to dyes, and their application often avoiding light exposure, have had their photosensitive properties long overlooked. Therefore, the inventors hope to develop applications of essential oils in solar cell manufacturing. Summary of the Invention

[0006] One object of the present invention is to provide a use of essential oils in the manufacture of solar cells.

[0007] Another object of the present invention is to provide a method for manufacturing a solar cell, which allows essential oils to be applied to the electrode material of the solar cell.

[0008] Another object of the present invention is to provide a solar cell in which essential oil is included in the electrode as a photosensitive material, and which can effectively perform energy conversion in an indoor environment.

[0009] To achieve the above objectives, the present invention provides a solar cell comprising: a first conductive glass; a first electrode material layer disposed on a first inner surface of the first conductive glass; a second conductive glass having a second inner surface opposite to the first inner surface of the first conductive glass; a second electrode material layer disposed on the second inner surface of the second conductive glass; and an electrolyte filling the space between the first electrode material layer and the second electrode material layer. Specifically, the first electrode material layer is composed of a mixture of essential oil, surfactant, and titanium dioxide, and after absorbing light, it can provide electrons during the discharge of the solar cell.

[0010] In one embodiment, the essential oil contained in the first electrode material layer is selected from the group consisting of bergamot essential oil, lavender essential oil, lemon verbena essential oil, ginger essential oil, grapefruit essential oil, angelica root essential oil, and combinations thereof.

[0011] In one embodiment, the essential oil contained in the first electrode material layer is selected from essential oils containing coumarins, furanocoumarins, limonene, citronellol, lavenderol, thymol, and combinations thereof.

[0012] In one embodiment, the first electrode material layer includes a highly lipophilic surfactant selected from essential oil emulsifiers with an HLB value between 8 and 18 or SPAN 80 with an HLB value of 4.3.

[0013] In one embodiment, the second electrode material layer contains graphene oxide.

[0014] In another aspect, the present invention also provides a method for manufacturing a solar cell, the steps of which include: A first electrode material was prepared by mixing essential oils and titanium dioxide with a surfactant. The first electrode material is coated onto a first conductive glass and then baked to form a first electrode material layer. A second electrode material layer is formed on a second conductive glass; and Electrolyte is injected between the first electrode material layer and the second electrode material layer.

[0015] In one embodiment, the method further includes: adjusting the baking time of the first electrode material at 150°C to change the conversion efficiency of the solar cell.

[0016] In one embodiment, the steps for preparing the first electrode material include: Provide a surfactant; The surfactant and the essential oil are mixed in a specific ratio; Adjusting this specific ratio changes the conversion efficiency of the solar cell.

[0017] In one embodiment, the baking time is 5, 8, 10, 12 or 15 minutes, and the ratio of the surfactant to the essential oil is 1:1 to 1:3.

[0018] Furthermore, the present invention also provides a use of an essential oil for manufacturing the aforementioned solar cell, serving as a negative electrode material of the solar cell.

[0019] This invention utilizes essential oils as electrode materials for solar cells, and further adjusts the baking time, the ratio of surfactant to essential oil, or selects different surfactants to obtain solar cells with better photoelectric conversion efficiency. Therefore, this invention provides an essential oil solar cell with high conversion efficiency, operating in a high-voltage, low-current mode, for use in everyday consumer products. Simple Explanation of the Diagram

[0020] Figure 1 is a schematic diagram of a solar cell using essential oil as a photosensitive material according to one embodiment of the present invention.

[0021] Figure 2 is a schematic flowchart of a method for manufacturing an essential oil-sensitized solar cell according to one embodiment of the present invention.

[0022] Figure 3 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell made from six single essential oils according to one embodiment of the present invention as a function of baking time.

[0023] Figure 4 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell made from a mixture of three essential oils according to one embodiment of the present invention as a function of baking time.

[0024] Figure 5 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured according to one embodiment of the present invention when the ratio of essential oil emulsifier to bergamot essential oil is adjusted to 1:1 to 1:3, as a function of baking time.

[0025] Figure 6 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured by adjusting the ratio of essential oil emulsifier to lavender essential oil to 1:1 to 1:3 according to one embodiment of the present invention, as a function of baking time.

[0026] Figure 7 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured according to one embodiment of the present invention when the ratio of essential oil emulsifier and lemon verbena essential oil is adjusted to 1:1 to 1:3, as a function of baking time.

[0027] Figure 8 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured according to one embodiment of the present invention when the ratio of essential oil emulsifier and dual essential oil mixture is adjusted to 1:1 to 1:3, as a function of baking time.

[0028] Figure 9 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured according to one embodiment of the present invention when the ratio of essential oil emulsifier and the mixture of three essential oils is adjusted to 1:1 to 1:3, as a function of baking time.

[0029] Figure 10 is a schematic diagram showing the change in photoelectric conversion efficiency of a solar cell manufactured using two different surfactants according to one embodiment of the present invention as a function of baking time. Implementation

[0030] The foregoing description and other technical contents, features and effects of this invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings.

[0031] [No.] [1] [Example:] Solar cells using essential oils as photosensitive materials

[0032] Figure 1 illustrates a solar cell 100 using essential oil as a photosensitive material according to one embodiment of the present invention, which is also referred to as an "essential oil-sensitized solar cell" or "essential oil solar cell" in the following embodiments. The solar cell 100 includes a first electrode 110, a second electrode 120, and an electrolyte 130 between them. The first electrode 110 is composed of a first conductive glass 112 and a first electrode material layer 114. The first electrode material layer 114 is formed on a first inner surface 112a of the first conductive glass 112. The second electrode 120 is composed of a second conductive glass 122 and a second electrode material layer 124. The second conductive glass 122 has a second inner surface 122a relative to the first inner surface 112a of the first conductive glass 112. The second electrode material layer 124 is formed on the second inner surface 122a of the second conductive glass 122. The electrolyte 130 fills the space between the first electrode material layer 114 and the second electrode material layer 124.

[0033] As shown in Figure 1, the first electrode 110 of the solar cell 100 is the negative electrode, serving as the anode or oxidation electrode during discharge; the second electrode 120 is the positive electrode, serving as the cathode or reduction electrode during discharge. Both the first conductive glass 112 and the second conductive glass 122 can be made of ITO film glass, for example, ITO film glass with a thickness of 0.4 mm, a length and width of 10 x 10 mm, and an impedance of 7 Ω. The first electrode material layer 114 comprises a mixture of essential oil, surfactant, and titanium dioxide (TiO2). The second electrode material layer 124 can use graphene oxide as the material. The electrolyte 130 needs to be matched with the electrode materials of the positive and negative electrodes. In this embodiment, potassium iodide electrolyte is used, for example, an electrolyte solution prepared from 0.5 M potassium iodide, 0.05 M iodine, and ethylene glycol.

[0034] In this invention, it is noteworthy that the first electrode material layer 114 must contain essential oil. Essential oil plays a crucial role as a photosensitizing material for the negative electrode. Under the photosensitivity of essential oil, it undergoes electron transfer after absorbing sunlight, which is closely related to its internal chemical structure. Essential oils consist of various organic molecules, such as terpenes, phenols, and esters. The light-absorbing portions of these components typically contain conjugated double bond systems or aromatic ring structures. These structures are essential for the photosensitivity of essential oils because they can absorb specific wavelengths from ultraviolet to visible light, thus making essential oils excellent photosensitizing materials.

[0035] As shown in Figure 1, the first electrode material layer 114 must contain TiO2 in addition to essential oil. When the conjugated double bond system in the essential oil molecule absorbs light energy, electrons in the molecule will transition from the ground state to the excited state, forming electron-hole pairs. These electrons will then be released from the excited state of the essential oil and enter the conduction band of titanium dioxide (TiO₂), simultaneously forming oxidized essential oil at the negative electrode. When electrons pass through the conduction band of TiO₂ and reach the positive electrode via the external circuit, the oxidized essential oil will be reduced by the redox pair (I⁻ / I₃⁻) in the electrolyte, while I₃⁻ in the electrolyte at the positive electrode accepts electrons passing through the external circuit and is reduced to I⁻. These I⁻ ions will diffuse back to the opposite negative electrode, undergoing a new oxidation half-reaction to generate I₃⁻, thus completing the battery cycle.

[0036] In one embodiment, TiO₂ must have nanoscale pores. The pore size and internal crystal orientation of TiO₂ also have a significant impact on the photoelectric conversion efficiency (hereinafter referred to as "conversion efficiency") of the solar cell 100. Nanoscale pores can increase the adsorption of essential oil molecules, thereby promoting electron transport and improving the photoelectric conversion efficiency.

[0037] In an embodiment of the present invention, the photoelectric conversion efficiency η of the battery is calculated according to the following formula (1): (1) in, , is the fill factor; Voc is the open-circuit voltage, which is the voltage measured when the circuit has infinite resistance; Isc is the short-circuit current, the current measured per unit current when the circuit is short-circuited; Vmp is the maximum voltage, which is the voltage corresponding to the maximum power point in the battery voltage-voltage curve (IV curve); Imp is the maximum current, which is the current corresponding to the maximum power point in the battery voltage curve (IV curve). Pin represents the light power emitted by the light source onto the battery, which can be measured using an optical power meter.

[0038] When selecting suitable essential oils, their light absorption capacity and whether they contain photosensitive components should be considered. Most essential oils with these properties come from the leaves of plants, especially citrus oils such as lemon and grapefruit. Conversely, woody essential oils generally do not possess these properties; therefore, this invention did not select woody essential oils such as cypress or eucalyptus oil.

[0039] Based on the above conditions, this invention utilizes absorption spectroscopy measurements to select six essential oils with photosensitivity covering different wavelengths, including bergamot essential oil, lavender essential oil, ginger essential oil, grapefruit essential oil, angelica root essential oil, and lemon verbena essential oil. These essential oils all possess similar light absorption properties, such as lavenderol in lavender essential oil and limonene in lemon verbena essential oil; their conjugated structures and aromatic rings can improve photoelectric conversion efficiency. These essential oils are not only readily available but also possess relatively stable photosensitivity, making them ideal choices for low-cost solar cell materials. In one embodiment, the essential oil contained in the first electrode material layer 114 can be selected from essential oils containing photosensitizing components such as coumarins, furanocoumarins, limonene, citronellol, lavenderol, and thymol.

[0040] To effectively reduce the surface tension of the mixture formed by titanium dioxide (TiO2) and essential oils, and to ensure its more uniform distribution on the ITO film glass, the first electrode material layer 114 must also contain a surfactant. Surfactants play a crucial role in the fabrication of the solar cell 100, especially in improving the quality and stability of the first electrode material layer 114. Since this invention uses essential oils as the light-absorbing medium for the solar cell, a relatively oleophilic surfactant is selected. The surfactant is chosen based on its hydrophilic-lipophilic balance number (HLB value), for example, an essential oil emulsifier with an HLB value between 8 and 18, or SPAN 80 (sorbitan oleate) with an HLB value of 4.3. Examples 2 to 5 below all use essential oil emulsifiers; example 6 uses SPAN 80 instead.

[0041] [No.] [2] [Example: Method for manufacturing essential oil-sensitized solar cells]

[0042] As shown in Figure 2, the manufacturing process of solar cell 100 is as follows:

[0043] First, the first electrode material is prepared (S11): essential oil and TiO2 are mixed using a surfactant. The surfactant used is an essential oil dispersing agent, which is a transparent gel that helps the essential oil mix evenly with other liquids. The commonly used ratio of essential oil dispersing agent to essential oil is typically between 1:1 and 1:4. In this embodiment, the essential oil dispersing agent and essential oil are first mixed at a ratio of 1:1 to 1:3. The mixture is then mixed evenly with TiO2 and dilute acetic acid to form a TiO2-essential oil mixture. The essential oil dispersing agent is crucial for the solution prepared by mixing essential oil with TiO2 and dilute acetic acid. Without it, the mixture may separate or stratify, affecting the stability of the solar cell. Dilute acetic acid can adjust the electrolyte solution to a suitable pH, improving the photoelectric conversion efficiency.

[0044] Next, the uniformly mixed TiO2 essential oil mixture is applied to the first conductive glass 112 (S21). For example, the TiO2 essential oil mixture is applied to an ITO film glass to ensure that the application area is fixed and the excess is scraped off to form a first electrode material layer 114 with a thickness of about 10 μm.

[0045] In addition, a second electrode material is prepared (S12), and the second electrode material is coated onto the second conductive glass 122 (S22). For example, graphene oxide is used as the second electrode material and is coated onto another ITO film glass to form a second electrode material layer 124.

[0046] After completing the above coating procedure, the first electrode (negative electrode) 110 coated with TiO2 essential oil mixture and the second electrode (positive electrode) 120 coated with graphene oxide are placed together in an oven at 150°C for baking (S30), and the baking time is adjusted.

[0047] After baking, place the positive and negative electrodes in a cool place to cool before bonding (S40). While waiting for cooling, prepare a gap material that fixes the gap between the two electrodes at 7 μm. After cooling, apply the gap material to the edge areas on both opposite sides of the electrodes and then join the two electrodes together, ensuring that the gap between the two electrodes remains consistent.

[0048] Finally, fill with electrolyte 130 (S50). Using a microdropper, add 0.5M potassium iodide electrolyte to one edge of the two electrodes. Through capillary action, the electrolyte will permeate between the two electrodes, and the solar cell 100 is thus completed.

[0049] In the following embodiments, the selection of essential oils, baking time, ratio of surfactants to essential oils, and types of surfactants used are analyzed to identify the optimal process conditions for achieving the photoelectric conversion efficiency of solar cells.

[0050] [No.] [3] [Example: Photoelectric conversion efficiency of a single essential oil at different baking times]

[0051] This embodiment is based on the manufacturing method of the previous embodiment. It selects six essential oils, namely bergamot essential oil, angelica root essential oil, lemon verbena essential oil, ginger essential oil, lavender essential oil and grapefruit essential oil, and compares the photoelectric conversion efficiency of solar cells made at 150°C with different baking times.

[0052] The inventors of this case discovered that the presence of limonene in essential oils has a substantial impact on the conversion efficiency of essential oil solar cells. As shown in Figure 3, it can be seen that the solar cell made using lemon verbena essential oil has the highest conversion efficiency among the six essential oils when both electrodes are baked for 8 minutes, and the optimal open-circuit voltage can reach 0.338 volts, which is the second highest power generation voltage among all single essential oils.

[0053] In addition, when the baking time is 12 minutes, the bergamot essential oil solar cell can generate a voltage of 0.428 volts, which is the highest among the six essential oils tested.

[0054] Another notable product is lavender essential oil, which contains lavender esters. After testing, when the electrodes of a solar cell sensitized with lavender essential oil were baked at 150°C for 10 minutes, the cell generated 0.264 volts. When the baking time was increased to 12 minutes, the conversion efficiency of the lavender essential oil solar cell was optimal among all baking times. This indicates that the electrode temperature of the solar cell made with lavender essential oil, when baked at 150°C for 12 minutes, represents the upper limit of the lavender essential oil's effective temperature range.

[0055] Based on the results above and Figure 3, it can be concluded that baking time does indeed affect the conversion efficiency of essential oil solar cells. The upper limit temperature of essential oil solar cells made from each essential oil is different. However, all six essential oils have one thing in common: when the baking time is too long and the temperature rises above the upper limit temperature that the essential oil can withstand, the conversion efficiency will not exceed the highest efficiency value afterward.

[0056] [No.] [4] [Example: Photoelectric conversion efficiency of a dual essential oil mixture at different baking times]

[0057] In this embodiment, three more essential oils—bergamot, lavender, and lemon verbena—were selected from the six essential oils in the third embodiment. Any two of these oils were mixed, with the ratio set at 1:1. These three essential oils contain citrus esters, lavender esters, and limonene, respectively. Therefore, this embodiment uses a mixture of essential oils with different components to create an essential oil solar cell, and measures the photoelectric conversion efficiency of the essential oil solar cell at different baking times.

[0058] Figure 4 is a line graph showing the conversion efficiency of an essential oil solar cell made with a dual essential oil blend at different baking times. The results show that mixing bergamot and lavender essential oils significantly improves the conversion efficiency of the solar cell. The upper limit of baking time for the essential oil solar cell also increased from 5 minutes and 8 minutes to 15 minutes. The conversion efficiency also showed a significant improvement with baking time. The conversion efficiency of the essential oil cell reached its peak at 15 minutes, surpassing six other essential oil solar cells made with a single essential oil.

[0059] When bergamot and lemon verbena essential oils are used together, the resulting essential oil solar cell exhibits stable performance under various baking times. In multiple tests, the open-circuit voltage of this cell consistently exceeded 0.3 volts, a voltage threshold never before reached by other experimental combinations. Although its conversion efficiency, even at its peak, is not as high as the previous combination using bergamot and lavender essential oils, the lemon verbena and bergamot combination still demonstrates considerable good performance in other indicators, showcasing its potential value as an essential oil solar cell material.

[0060] Overall, in the process of manufacturing essential oil solar cells, mixing different essential oils and adjusting the baking time of the electrode material layers can indeed improve the conversion efficiency and enhance the tolerance limits of essential oil solar cells to baking time and temperature. As shown in Figure 4, the essential oil solar cell made by mixing bergamot essential oil and lavender essential oil has a significantly better photoelectric conversion efficiency.

[0061] [No.] [5] [Example: Adjusting the ratio of surfactants and essential oils]

[0062] [5-1.] [The effect of the ratio of emulsifier to single essential oil on conversion efficiency]

[0063] Bergamot, lavender, and lemon verbena essential oils were used. During the manufacturing process, only the ratio of the essential oil emulsifier to the essential oil was changed. The photoelectric conversion efficiency of the essential oil battery under various baking times after changing the ratio of the essential oil emulsifier to each essential oil is shown in Figures 5 to 7.

[0064] As shown in Figure 5, it can be observed that the conversion efficiency of the bergamot essential oil solar cell changes significantly when the ratio of essential oil emulsifier to bergamot essential oil is 1:1. Compared to the bergamot essential oil solar cell made with a ratio of essential oil emulsifier to bergamot essential oil of 1:2, aside from the initial lower cell efficiency, as the baking time increases, the change in electrode temperature surpasses that of the 1:2 ratio bergamot essential oil solar cell. Furthermore, the maximum temperature resistance also increases to 8 minutes of baking.

[0065] When the ratio of essential oil emulsifier to essential oil is increased to 1:3, the efficiency of the essential oil solar cell shows a significant increase compared to ratios of 1:1 and 1:2. The electrode temperature is most suitable for this ratio after baking for another 8 minutes, thus the efficiency of the essential oil-sensitized solar cell reaches its peak, increasing the efficiency of the bergamot-based essential oil solar cell to 0.039%. Therefore, when using bergamot essential oil as the light-absorbing layer of an essential oil solar cell, this effect can be achieved by adjusting the ratio of essential oil emulsifier to essential oil according to specific needs.

[0066] As shown in Figure 6, a 1:1 ratio is ideal for solar cells made from lavender essential oil. Under different baking times, the conversion efficiency is higher in three time periods than in the other two ratios. Among them, the temperature at which the baking time is 10 minutes is the most ideal temperature for this ratio.

[0067] The optimal conversion efficiency of the essential oil solar cell made using lemon verbena essential oil is achieved when the ratio is 1:2 and the baking time is 8 minutes.

[0068] [5-2.] [The effect of the ratio of emulsifier to dual essential oil mixture on conversion efficiency]

[0069] As demonstrated in Example 4, the conversion efficiency of the solar cell is better when bergamot oil and lavender oil are mixed compared to other combinations. Therefore, this example uses a mixture of bergamot oil and lavender oil, and further mixes the emulsifier with this mixture in different proportions to manufacture a solar cell, and measures its conversion efficiency.

[0070] Figure 8 shows that the optimal battery conversion efficiency still occurs at the temperature when the ratio of essential oil emulsifier to essential oil is 1:2 and the baking time is 15 minutes, with a battery conversion efficiency of 0.43%. When the ratio is adjusted to 1:1, the battery conversion efficiency remains above 0.03% after 15 minutes of baking. This embodiment demonstrates that by adjusting the appropriate ratio and temperature according to different needs, the essential oil solar cell can perform better. Essential oil solar cells have different functions at various ratios and temperatures, which is the flexibility of essential oil solar cells.

[0071] [5-3.] [The effect of the ratio of emulsifier to the three essential oils mixture on conversion efficiency]

[0072] As shown in Figure 9, when the ratio of essential oil emulsifier to the three essential oil mixture is 1:1 and the baking time is 10 minutes, the conversion efficiency of the essential oil solar cell reaches the best among the three different ratios. Furthermore, the performance of the essential oil solar cell made from the three essential oil mixture can be improved by precisely controlling the temperature and baking time.

[0073] As can be seen from the fifth embodiment, changing the ratio of essential oil emulsifier to essential oil can indeed affect the photoelectric conversion efficiency of essential oil-sensitized solar cells, and the effect on conversion efficiency is positive.

[0074] [No.] [6] [Example: Usage] [SPAN 80] [Impact on conversion efficiency]

[0075] SPAN 80, another lipophilic surfactant, works similarly to essential oil emulsifiers and can also improve the stability of essential oil solar cells.

[0076] In this embodiment, a mixture of bergamot essential oil and lavender essential oil is selected, and the selected surfactant is replaced with the more oleophilic SPAN 80 (with an HLB value of 4.3) according to a 1:2 ratio of surfactant to the mixture of essential oils to manufacture solar cells.

[0077] As shown in Figure 10, after using SPAN 80, the resulting essential oil solar cells can achieve similar effects to those made with essential oil emulsifiers.

[0078] [No.] [7] [Example: How to use essential oil solar cells]

[0079] After researching batteries, an attempt was made to apply solar cells to small devices, such as a lucky cat figurine. First, the original small solar panel on the lucky cat was removed, and five newly fabricated solar cells were connected in series. These five solar cells were made from a combination of bergamot and lavender essential oils, with an oil emulsifier-to-oil ratio of 1:2, and were baked for 15 minutes. The original small solar panel on the lucky cat, consisting of five solar cells, could generate 2 to 3 volts under normal lighting. After connecting the oil-sensitized solar cells in series, the measured total voltage was approximately 2.3 to 2.5 volts, similar to the original solar panel.

[0080] In summary, the present invention primarily provides a use for an essential oil in the manufacture of a solar cell. This essential oil is used as an electrode material in the solar cell, which, after absorbing light, provides electrons during the solar cell's discharge.

[0081] Furthermore, the present invention also provides a method for manufacturing a solar cell and the solar cell formed therefrom. The manufacturing method includes the following steps: mixing essential oil and titanium dioxide with a surfactant to prepare a first electrode material; applying the first electrode material onto a first conductive glass and baking it to form a first electrode material layer; forming a second electrode material layer on a second conductive glass; and injecting an electrolyte between the first electrode material layer and the second electrode material layer, thereby completing an essential oil-sensitized solar cell.

[0082] Accordingly, the present invention utilizes the photosensitivity of essential oils as the light-absorbing material of solar cells, thereby providing an essential oil solar cell with high conversion efficiency, which is a high-voltage, low-current mode. It can be applied to daily necessities by connecting essential oil solar cells in series to enable them to function.

[0083] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the invention are still within the scope of the patent. Furthermore, no embodiment or claim of the present invention needs to achieve all the objectives, advantages, or features disclosed in the invention. In addition, the abstract and headings are merely for assisting in patent document searches and are not intended to limit the scope of the invention.

[0084] 100: Solar cells 110: First electrode 112: First conductive glass 114: First electrode material layer 120: Second electrode 122: Second conductive glass 124: Second electrode material layer 130: Electrolyte S11~S12, S21~S22, S30~S50: Manufacturing process flow of solar cells

Claims

1. A solar cell, comprising: First conductive glass; A first electrode material layer is disposed on a first inner surface of the first conductive glass, and the first electrode material layer comprises a mixture of a photosensitive material, a surfactant, and titanium dioxide, wherein the photosensitive material is an essential oil that does not contain terpineol and does not contain dyes, wherein the surfactant is used to emulsify the essential oil rather than as a dispersant for the titanium dioxide particles, wherein the essential oil is selected from the group consisting of bergamot essential oil, lavender essential oil, lemon verbena essential oil, ginger essential oil, grapefruit essential oil, angelica root essential oil, and combinations thereof, or selected from essential oils containing coumarins, furanocoumarins, limonene, citronellol, lavenderol, thymol, and combinations thereof; a second conductive glass having a second inner surface relative to the first inner surface of the first conductive glass; a second electrode material layer is disposed on the second inner surface of the second conductive glass and contains graphene oxide; and an electrolyte is filled between the first electrode material layer and the second electrode material layer.

2. The solar cell of claim 1, wherein the surfactant in the first electrode material layer is selected from essential oil emulsifiers with an HLB value between 8 and 18 or SPAN 80 with an HLB value of 4.3, wherein the HLB value is a hydrophilic-lipophilic balance value.

3. A method for manufacturing a solar cell, comprising: A first electrode material is prepared by mixing essential oil and titanium dioxide with a surfactant, wherein the essential oil is used as a photosensitive material, is free of terpineol and dyes, and the surfactant is used to emulsify the essential oil rather than as a dispersant for the titanium dioxide particles. The essential oil is selected from the group consisting of bergamot oil, lavender oil, lemon verbena oil, ginger oil, grapefruit oil, angelica root oil, and combinations thereof, or from essential oils containing coumarins, furanocoumarins, limonene, citronellol, lavenderol, thymol, and combinations thereof. The first electrode material is coated onto a first conductive glass and baked to form a first electrode material layer. A second electrode material layer is formed on a second conductive glass, wherein the second electrode material layer contains graphene oxide. An electrolyte is injected between the first electrode material layer and the second electrode material layer.

4. The method as described in claim 5, further comprising: The conversion efficiency of the solar cell can be changed by adjusting the baking time of the first electrode material at 150°C.

5. The method as described in claim 6, wherein the step of preparing the first electrode material comprises: The surfactant and the essential oil were mixed in a certain proportion; And by adjusting that specific ratio to change the conversion efficiency of the solar cell.

6. The method as described in claim 7, wherein the baking time is 5, 8, 10, 12 or 15 minutes, and the ratio of the surfactant to the essential oil is 1:1 to 1:

3.

7. The use of an essential oil in the manufacture of the solar cell of claim 1, wherein the essential oil is used as a photosensitive material in the negative electrode of the solar cell, rather than as a solvent or binder for the material contained in the negative electrode.

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