A solar panel having a photoluminescence property and a method for the integration of glass nanocomposites that enable the solar panel to have a photoluminescence property

Abstract

The invention relates to a solar panel configured to be used simultaneously in the agriculture and energy sectors, which, by means of the components it contains, is capable of optimizing plant growth by absorbing the UV, blue, and green wavelengths of sunlight at adjustable ratios and converting them into red light, while at the same time increasing the energy conversion efficiency in solar cells, and also relates to a method for integrating glass nanocomposites that enable said solar panel to have photoluminescent properties into solar panels.

Description

[0001] A SOLAR PANEL HAVING A PHOTOLUMINESCENCE PROPERTY AND A METHOD FOR THE INTEGRATION OF GLASS NANOCOMPOSITES THAT ENABLE THE SOLAR PANEL TO HAVE A PHOTOLUMINESCENCE PROPERTY

[0002] TECHNICAL FIELD

[0003] The invention relates to a solar panel configured to be used simultaneously in the agriculture and energy sectors, which, by means of the components it contains, is capable of optimizing plant growth by absorbing the UV, blue, and green wavelengths of sunlight at adjustable ratios and converting them into red light, while at the same time increasing the energy conversion efficiency in solar cells, and also relates to a method for integrating glass nanocomposites that enable said solar panel to have photoluminescent properties into solar panels.

[0004] PRIOR ART

[0005] Photovoltaic cells are devices that convert solar energy into electrical energy. These cells are generally manufactured from semiconductor materials such as silicon. The operation of photovoltaic cells begins when photons interact with the semiconductor material and release the electrons within this material. Subsequently, the released electrons are collected at the electrodes, thereby generating electricity. Photovoltaic cells are brought together to form photovoltaic panels. Cells connected in series allow an increase in panel voltage, while cells connected in parallel allow an increase in panel current. Solar panels have a special importance among renewable energy sources due to the absence of moving parts, their cost-effectiveness, their very low maintenance requirement, and their very long service life (>25 years). As a low-cost source capable of generating energy close to humans, they have wide application areas in installations such as balconies, rooftops, parking lots, and the like.

[0006] Standard photovoltaic panels are manufactured with an aluminum frame and a structure comprising a front encapsulant, cells connected in series or in parallel, and a rear encapsulant between two sheets of glass. In order to generate more current per unit area, the distance between the cells is kept as small as possible (~1-2 mm). It is also possible to use a protective front polymer instead of glass on the front surface, a protective rearpolymer instead of glass on the rear surface, and durable composite materials instead of aluminum.

[0007] Photovoltaic panels are preferred as a sustainable energy source for electricity generation in homes and commercial buildings, for meeting energy demands in industrial facilities, and in regions with remote energy needs (for example, rural areas and islands). In addition, the use of photovoltaic panels is increasingly becoming widespread in areas such as portable devices, spacecraft, and the transportation sector (for example, solar-powered cars, yachts, tents, and caravans). Large-scale solar farms, on the other hand, play an important role in reducing dependence on fossil fuels by contributing to the energy grid.

[0008] The use of photovoltaic panels in agricultural areas is increasingly gaining popularity. In agricultural solar energy systems (which may be abbreviated as AgriPV), the panels are placed over the fields, enabling both energy generation and agricultural production to be carried out on the same land.

[0009] The main purpose of AgriPV systems is to convert the portion of solar energy that is excessive for plants and may have a negative effect on plant growth into energy, thereby providing both electricity generation and an increase in agricultural yield. In addition, AgriPV systems reduce water loss from soil and plants by creating a microclimate beneath the solar panels, thus making water use more efficient. With these characteristics, AgriPV systems offer sustainable energy and production solutions in agricultural areas.

[0010] In existing AgriPV systems, standard photovoltaic panels are generally used. These panels are designed to absorb light at a rate close to 100%. Therefore, in AgriPV systems, standard photovoltaic panels are placed intermittently in order not to completely cover the field. However, in this case, plants that remain in the shadow of the photovoltaic panel cannot receive sunlight, while other plants receive direct sunlight. This situation prevents a homogeneous distribution of light in the field and makes the microclimate effect that AgriPV systems can create limited.

[0011] In recent years, special panels in which photovoltaic cells are placed within the panels with gaps left between them have begun to be used for experimental purposes in AgriPV systems. However, these special panels do not have the capability to modify or manage the spectrum of sunlight in order to optimize agricultural production and energy generation. This situation constitutes one of the main shortcomings of AgriPV systems. In particular, the insufficient amount of light at certain wavelengths that plants need more compared toother wavelengths (for example, red light) reaching the plants causes the increase in yield to remain limited.

[0012] In the existing art, in order to overcome these light absorption problems, solar panels containing quantum dot components are being developed. Quantum dots may undergo degradation when exposed to polar solvents such as water, high temperatures, and intense radiation due to their strong ionic structures and high surface energies. Therefore, in order for quantum dots to maintain their superior emission properties for a long time, they need to be encapsulated within a material that is thermally, chemically, and mechanically stable.

[0013] However, quantum dots, which are more sensitive to environmental factors compared to conventional photovoltaic cells, are adversely affected by dust, dirt, humidity, and agricultural chemicals to which solar panels used in agricultural areas are continuously exposed. These environmental conditions weaken the structural integrity and emission efficiency of the quantum dots, and prolonged exposure to sunlight increases the rate of degradation, thereby reducing emission performance.

[0014] As a result, all of the problems mentioned above have made it necessary to introduce an innovation in the relevant technical field.

[0015] BRIEF DESCRIPTION OF THE INVENTION

[0016] As is known in the art, solar panels are widely used as devices that directly convert sunlight into electrical energy. In particular, AgriPV systems used in agricultural areas aim to increase energy efficiency and ensure agricultural sustainability by combining solar energy production with agricultural production. However, existing AgriPV systems cannot effectively utilize the broad spectrum of sunlight, cannot deliver sufficient amounts of light at certain wavelengths needed by plants, and exhibit low energy conversion efficiency depending on the total surface area of the solar cells.

[0017] This invention enables more efficient use of sunlight in terms of both plant growth and energy production by pulverizing glass nanocomposites containing quantum dots and / or lanthanide ions as photoluminescent components and using them between solar panels in order to eliminate the deficiencies of the existing art. This approach aims to increase the effectiveness of photovoltaic panels in both agricultural production and energy generation.The purpose of the invention is to make sunlight more efficient in terms of plant development by using glass nanocomposites containing photoluminescent components in AgriPV systems. This glass nanocomposite absorbs photons in the UV, blue, and green regions of sunlight, which plants require less, at adjustable ratios, and emits light in the red region, which is of critical importance for plant growth. In addition, the light scattered and emitted from the glass nanocomposites and the red light generated as a result of photoluminescence reach the solar cells in the panel, thereby increasing energy production efficiency. As stated in the invention, it has been determined that AgriPV systems obtained with glass nanocomposites containing photoluminescent components produce approximately 1% more power compared to PV panels in the existing art.

[0018] In addition, the application of these panels in agricultural lands under conditions of intense sunlight provides water savings and improves soil quality. Thus, a significant advantage is offered in terms of energy production and agricultural sustainability.

[0019] Another objective of the invention is to optimize the energy conversion efficiency in solar panels through spectral conversion, homogeneous light distribution, reduction of optical losses, and photoluminescence effects. The glass nanocomposites containing photoluminescent components included in the invention convert high-energy UV, blue, and green light into red light, which can be used more efficiently by solar cells, by absorbing them at adjustable ratios through a down-conversion energy conversion mechanism. In this way, a greater number of photons, at wavelengths that can be efficiently utilized by the solar cells, are directed to the solar cells. These glass nanocomposites, which provide homogeneous light distribution and high light transmittance, offer balanced and homogeneous energy production across the entire surface of the panel. In addition, the glass nanocomposites in question enable light to reach the plant in a diffused manner rather than directly, thereby making it possible for the plant to benefit effectively from the light.

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021] In this detailed description, the invention relates to a solar panel and is explained by means of examples that are intended solely to provide a better understanding of the subject matter and that do not create any limiting effect.

[0022] The solar panel addressed in this invention comprises at least one solar cell. This solar cell is the fundamental component of solar panels and provides the function of directlyconverting sunlight into electrical energy. It may be manufactured from materials known in the art, and the scope of protection of the invention is independent of what this material is.

[0023] At least one encapsulant material is located in the lower neighborhood and / or the upper neighborhood of the said solar cell. The encapsulant material is present to both protect the solar cells from environmental factors and to ensure structural integrity. It may be manufactured from materials known in the art, and the scope of protection of the invention is independent of what this material is. In a preferred embodiment, the encapsulant material comprises at least two encapsulant materials located in the lower and upper neighborhoods of the solar cell.

[0024] The said solar panel comprises at least two protective layers located at the bottommost and topmost positions so as to include the other components as well. The protective layers physically protect the solar panels against environmental factors, thereby ensuring a long service life of the product. These layers provide resistance against external effects such as moisture, dust, wind, and impact, and at the same time, enable sunlight to reach the solar cells with maximum efficiency thanks to their high light transmittance. The protective layers increase the mechanical durability of the solar panels by providing structural integrity and optimize energy production by minimizing light losses. These layers may be manufactured from materials known in the art, and the scope of protection of the invention is evaluated independently of the type of material used.

[0025] In this invention, the term AgriPV systems is frequently used instead of solar panels. AgriPV systems aim to perform agricultural production and energy production simultaneously. AgriPV systems allow both plant cultivation and electricity generation by placing solar panels over agricultural lands. The solar panels addressed in the present invention are essentially a system that can be used as AgriPV.

[0026] In the following lines, the term quantum dot will be mentioned. These quantum dots are nanoscale semiconductor crystalline materials with properties such as high absorption cross-section, band gap energy that can vary depending on their size, tunable emission wavelength, and high photoluminescence quantum efficiency. Due to these properties, quantum dots have high potential for use in various emission color conversion applications. The sizes of these quantum dots may generally be in the range of 1 to 20 nm.

[0027] The main objective of the invention is for the solar panels addressed to have photoluminescent properties. There are methods and practices known in the art to providethis property. In the existing art, in order to provide photoluminescent properties in AgriPV systems, coatings containing quantum dots and / or lanthanides and / or phosphors and / or organic dye-polymers are frequently used. However, phosphor-based coatings and organic materials, which are materials used in the art, tend to degrade over time against environmental factors such as UV radiation and high temperatures, which causes performance loss for AgriPVs. Lanthanides, on the other hand, can efficiently convert only a very limited portion of the light coming from the sun into the visible region due to their low absorption cross-sections. Quantum dots, although providing high photoluminescence efficiency, have low chemical stability, costly production processes, and some types pose environmental risks due to their toxic effects.

[0028] In the present invention, enabling the solar panels to have photoluminescent properties makes it possible to provide ideal light conditions for energy efficiency and plant growth. Through this property, high-energy wavelengths of sunlight such as UV, blue, and green light are absorbed at adjustable ratios and converted into red light, which is more suitable for photosynthesis. On the other hand, by means of the photoluminescent property, greater electrical energy production is achieved both by converting high-energy photons that cannot be absorbed by the cell into lower-energy photons that the cell can absorb (for example, red light) and by concentrating more photons on the cell through photons generated as a result of luminescent emission. As a result, more electrical energy is obtained per unit cell area with the same amount of light, which increases the overall energy conversion efficiency of the panel.

[0029] In this invention, the expression “absorption at adjustable ratios” refers to the ability of solar panels to absorb light at a specific wavelength at different ratios. In this context, by “absorption at adjustable ratios” in the invention, values in the range of 20% to 80% are meant. The characterized solar panel is not designed to take a value of 0%, at which it is completely transparent, or a value of 100%, at which it absorbs all light. Therefore, absorption processes are carried out within the specified range of 20% to 80%. This range has been selected in order to support agricultural growth by transmitting the light wavelengths required by plants while simultaneously optimizing energy production. This feature enables the solar panels to provide an adaptable structure that meets both agricultural and energy production needs.

[0030] The solar panel subject to the present invention comprises glass nanocomposite powders exhibiting photoluminescent properties. Within the glass nanocomposite powders, at least one of quantum dots and / or lanthanides is homogeneously distributed as aphotoluminescent component. Owing to their high thermal and chemical stability properties, the glass nanocomposite powders protect the photoluminescent components against environmental factors while providing long-term photoluminescent performance and enabling these components to be positioned homogeneously in the solar panels; at the same time, they support efficient conversion of the light spectrum and preservation of optical transmittance.

[0031] In a preferred embodiment of this invention, at least one quantum dot is present as the photoluminescent component. In this invention, as the quantum dot, at least one of perovskite compounds expressed by the formula ABX3may be used, wherein A may comprise at least one of the group Cs, K, and Rb; B may comprise at least one of Pb, Sn, Bi, Ag, Zn, Fe, Cu, Ni, Cd, or the lanthanide group; and X may comprise at least one of the halogen group. In another preferred embodiment, the quantum dot comprises at least one of the group consisting of CdSe, CdTe, and ZnTe. In another preferred embodiment, the quantum dot may comprise at least one of the group consisting of InP and carbon-based nanocrystals. In the case where glass particles containing quantum dots are used as the photoluminescent component, the sizes of the quantum dots are in the range of 1 to 20 nm.

[0032] In a preferred embodiment of this invention, at least one lanthanide ion is present as the photoluminescent component. In a preferred embodiment, the lanthanide ions comprise at least one of the group consisting of Eu3+, Tb3+, Sm3+, or Yb3+.

[0033] In a preferred embodiment, lanthanide ions and quantum dots are homogeneously distributed as photoluminescent components within the glass matrix, and the coexistence of these two components enables conversion of sunlight over a broader spectral range, thereby providing a light spectrum optimized for energy production and agricultural efficiency; while the quantum dots provide broadband emission, the lanthanide ions support this conversion with narrowband and highly efficient emission characteristics.

[0034] The glass nanocomposites used in this invention are in the form of fine-grained powders with sizes ranging from 1 to 300 pm. This size range enables the glass nanocomposites to have a large surface area. The large surface area allows stronger interaction between the glass and the photoluminescent components, thereby making it possible to optimize light absorption and photon conversion processes. At the same time, this feature increases homogeneous light distribution, provides optical transparency, and enhances energy conversion efficiency by minimizing light loss. In addition, due to the large surface areas ofthe glass nanocomposite powders, light in the UV and visible wavelength ranges is effectively absorbed and converted into red light, which both optimizes plant growth and increases the energy conversion efficiency of the solar cells.

[0035] In a preferred embodiment, the glass nanocomposites containing the characterized photoluminescent components are ground to a specific particle size and converted into a fine-grained powder form. This means that, after the photoluminescent components are encapsulated within the glass nanocomposites, they are prepared as small particles suitable for application to solar panels. The grinding process mentioned herein is continued until a powder form having a particle size in the range of 1 to 300 pm is obtained.

[0036] The glass nanocomposite containing photoluminescent components subject to the invention partially absorbs photons in the UV, blue, or green regions coming from the sun, while providing high (70% and above) and adjustable transmittance.

[0037] In this invention, the glass nanocomposites containing photoluminescent components may be integrated into various layers of the solar panel structure:

[0038] - they may be positioned between the protective layer and the encapsulant materials, - they may be positioned between two encapsulant material layers.

[0039] In another preferred configuration of the invention, the glass nanocomposites containing photoluminescent components may be configured in various regions of the solar cells within the solar panel:

[0040] - the solar cells may be positioned at the edges of the solar panel, while glass nanocomposites containing photoluminescent components may be located in the central region,

[0041] - the solar cells may be positioned in the form of strips within the solar panel, and glass nanocomposites containing photoluminescent components may be located in the remaining regions,

[0042] - the solar cells and the glass nanocomposites containing photoluminescent components may be arranged in a checkerboard pattern within the solar panel, - the solar cells may be positioned in the central region of the solar panel, while glass nanocomposites containing photoluminescent components may be positioned at the edge regions.

[0043] - (The said arrangements are shown in the images shared as Figure 2.)In the invention, the glass nanocomposites containing photoluminescent components may be applied to solar panels by various methods. These include homogeneous distribution on the surface by a spray coating method, direct application onto the surface by a spreading method and fixation with encapsulating materials, and integration by compressing between two protective glass layers by a lamination method.

[0044] In the solar panel addressed in the invention, glass nanocomposites doped with quantum dots and / or lanthanide ions are pulverized and coated onto the interface of the panel glass, and by virtue of their emission color conversion properties, they absorb photons in the UV, blue, and green regions — which are less needed by plants — at adjustable ratios and emit light in the red region, which is more needed by plants, thereby enabling more effective utilization of sunlight in plant growth. In addition, the light scattered from the photoluminescent glass nanoparticles and the red light emitted as a result of their own emission reach the solar cells in the panel, thereby increasing efficiency.

[0045] In another aspect, the invention provides a method for obtaining the characterized glass nanocomposites containing photoluminescent components. The method in question comprises the following process steps:

[0046] - adding at least one of quantum dots and / or lanthanide ions as a photoluminescent component to glass batches and mixing said glass batch in a homogeneous manner,

[0047] wherein, within the glass batch mentioned, at least one of the glass groups based on silicate, borosilicate, alumina silicate, tellurite, and / or phosphate is preferred,

[0048] - subjecting the homogenized glass batch to melting processes by placing it into crucibles made of materials such as quartz, alumina, or platinum at a temperature in the range of 700 to 1500 °C, and obtaining molten glass,

[0049] - obtaining glass by pouring the obtained molten glass either into a mold made of materials such as stainless steel, brass, graphite, or copper maintained at room temperature or pre-heated, in parallel, or directly into deionized water,

[0050] - subjecting the obtained glass to stress-relief annealing at temperatures in the range of 300 to 500 °C in order to eliminate internal stresses resulting from rapid cooling processes,- subjecting the glass containing quantum dots to crystallization processes after the annealing processes,

[0051] wherein said crystallization processes are carried out in a controlled manner at a temperature in the range of 300 to 650 °C and the quantum dots are ensured to have sizes in the range of 1 to 20 nm, thereby obtaining glass nanocomposites,

[0052] - subjecting the obtained glass nanocomposites to grinding processes and converting them into a fine-grained powder having a particle size distribution in the range of 1 to 300 pm.

[0053] In another aspect, the invention relates to a method for integrating glass nanocomposites containing photoluminescent components into solar panels. The mentioned method comprises the following process steps:

[0054] - subjecting glass nanocomposites containing at least one of one or more quantum dots and / or one or more lanthanide ions as photoluminescent components to grinding processes and converting them into a fine-grained powder having a particle size distribution in the range of 1 to 300 pm,

[0055] - integrating the glass nanocomposites converted into fine-grained powder to a thickness of 1-300 pm between a protective layer and encapsulant materials or between two encapsulant material layers by applying at least one of spray coating, spreading, laminating, and combining with encapsulant material methods in a manner suitable for the location where they will be positioned in the solar panels,

[0056] wherein the positions mentioned for the glass nanocomposites and the solar cells in these panels are as follows:

[0057] - the solar cells are positioned at the edges of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the central region,

[0058] - the solar cells are positioned in the form of strips in the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the remaining regions,

[0059] - the solar cells and the glass nanocomposites containing photoluminescent components are positioned in a checkerboard pattern in the solar panel,the solar cells are positioned in the central region of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the edge regions.

[0060] The solar panels addressed in the invention are configured for AgriPV applications and comprise glass nanocomposites containing photoluminescent components. These solar panels both optimize plant development and increase energy production efficiency. Red light, which is of critical importance for plant growth, is delivered to crops in an increased manner and in the form of diffused light thanks to the ability of the glass nanocomposites containing photoluminescent components to convert the light spectrum. This situation is shown in Figure 1.

[0061] At the same time, the light emitted from the photoluminescent glass nanocomposites and the light obtained as a result of absorption at adjustable ratios are directed to the solar cells, thereby increasing the energy efficiency of the panel and enabling approximately 1% more power to be obtained compared to reference photovoltaic panels. Solar panels containing photoluminescent glass nanocomposites provide water savings, improve soil quality, and optimize the growth conditions of agricultural products by being used across agricultural lands under conditions of intense sunlight, thereby offering a new-generation AgriPV technology that maximizes energy agriculture synergy.

[0062] The scope of protection of the invention is defined in the claims provided in the annex and cannot be limited in any way to the examples described in this detailed description for illustrative purposes. Indeed, it is evident that a person skilled in the art may devise similar configurations in light of the above descriptions without departing from the main concept of the invention.

Claims

CLAIMS1. A solar panel configured to be used simultaneously in the agriculture and energy sectors, comprising at least one solar cell, at least one encapsulant material positioned below and / or above said solar cell, and at least one protective layer, characterized in that it comprises glass nanocomposites containing, as photoluminescent components, at least one of one or more quantum dots and / or one or more lanthanide ions that enable light having high-energy wavelengths such as UV, blue, or green to be absorbed at adjustable ratios and converted into lower- energy wavelengths such as red, and in that said glass nanocomposites containing photoluminescent components are in powder form.

2. A solar panel according to claim 1 , characterized in that said quantum dot comprises at least one of perovskite compounds expressed by the formula ABX3.

3. A solar panel according to claim 2, characterized in that said A comprises at least one of the group consisting of Cs, K, and / or Rb, said B comprises at least one of the group consisting of Pb, Sn, Bi, Ag, Zn, Fe, Cu, Ni, Cd, or a lanthanide element, and said X comprises at least one of the halogen group.

4. A solar panel according to claim 1, characterized in that it comprises, as the quantum dot, at least one of the group consisting of CdSe, CdTe, ZnTe, InP, and carbon-based nanocrystals.

5. A solar panel according to one of the preceding claims, characterized in that it comprises at least one of the group consisting of Eu3+, Tb3+, Sm3+, or Yb3+as the lanthanide ion.

6. A solar panel according to one of the preceding claims, characterized in that it comprises glass nanocomposites containing at least one quantum dot and at least one lanthanide ion as photoluminescent components.

7. A solar panel according to claim 6, characterized in that the particle size of the said quantum dots is in the range of 1 to 20 nm.

8. A solar panel according to one of the preceding claims, characterized in that the glass nanocomposites containing photoluminescent components are in powder form having a particle size in the range of 1 to 300 pm.

9. A solar panel according to one of the preceding claims, characterized in that the glass nanocomposites containing photoluminescent components are positioned in at least one of the following locations:- between the protective layer and the encapsulant materials,- between two encapsulant material layers.

10. A solar panel according to one of the preceding claims, characterized in that the glass nanocomposites containing photoluminescent components and the solar cells are positioned in at least one of the following configurations:- the solar cells are positioned at the edges of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the central region,- the solar cells are positioned in the form of strips in the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the remaining regions,- the solar cells and the glass nanocomposites containing photoluminescent components are positioned in a checkerboard pattern in the solar panel, - the solar cells are positioned in the central region of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the edge regions.

11. A method for integrating glass nanocomposites containing photoluminescent components into solar panels, characterized in that it comprises the following process steps:- subjecting glass nanocomposites containing at least one of one or more quantum dots and / or one or more lanthanide ions as photoluminescent components to grinding processes and converting them into a fine-grained powder having a particle size distribution in the range of 1 to 300 pm, - integrating the glass nanocomposites converted into fine-grained powder into solar panels between a protective layer and encapsulant materials or between two encapsulant material layers by applying at least one of spraycoating, spreading, laminating, and combining with encapsulant material methods in accordance with the designated locations and positions in the solar panels,wherein the positions of the glass nanocomposites and the solar cells in the solar panels are at least one of the following:- the solar cells are positioned at the edges of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the central region,- the solar cells are positioned in the form of strips in the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the remaining regions,- the solar cells and the glass nanocomposites containing photoluminescent components are positioned in a checkerboard pattern in the solar panel, - the solar cells are positioned in the central region of the solar panel, while glass nanocomposites containing photoluminescent components are positioned in the edge regions.

12. A method according to claim 11, characterized in that the glass nanocomposites comprise at least one of perovskite compounds expressed by the formula ABX3as the quantum dot.

13. A method according to claim 11, characterized in that the glass nanocomposites comprise, as the quantum dot, at least one of the group consisting of CdSe, CdTe, ZnTe, InP, and carbon-based nanocrystals.

14. A method according to one of claims 11 to 13, characterized in that the glass nanocomposites comprise at least one of the group consisting of Eu3+, Tb3+, Sm3+, or Yb3+as the lanthanide ion.

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