IL300382B1 - A tandem selective spectral absorbance solar cell and methods thereof - Google Patents

Description

300382/ A TANDEM SELECTIVE SPECTRAL ABSORBANCE AND TRANSMITTANCE SOLAR CELL AND METHODS THEREOF FIELD OF THE INVENTION The present invention pertains to a tandem selective spectral absorbance and transmittance solar cell and to agriphotovoltaic systems characterized by elevated selective spectral absorbance and transmittance solar cell configured to grow vegetative products below the elevated structures. The invention also related to method of manufacturing and using the systems in both small and industrial scales.

BACKGROUND OF THE INVENTION Producing meaningful amounts of electric power using photovoltaic solar cells requires a relatively large amount of area space, i.e., about 1.6 square meter produces 250 Watt at peak hours, or 2kWh per day in a typical sunny day. In order to accumulate meaningful amounts of energy, one requires vast amounts of land.

In recent years, some owners of farmland have started to utilize their land to generate electric energy by installing large amounts of photovoltaic panels due to the financial gains presented, often at the expense of the original agricultural use of the land. Others have found a way for the co-existence of photovoltaic modules alongside the original crops by physically dividing the space - putting photovoltaic modules on roofs of farm buildings, and in between rows of plants, in order to take advantage of the space not used for agricultural purposes. Usually, in order that the crops themselves get their required dose of sunlight energy, the use of photovoltaic panels on the same space is limited to 30-50%.

Photosynthesis is the main biological process by which plants convert the sunlight into a useful form of chemical energy which can later be utilized within the plant. Plants have specific requirements regarding the daily dose of light received, as well as the wavelengths of the light they require for a healthy plant life. Plants use different parts of the sunlight spectrum and require different light intensities during the various stages of plant growth. McCree’s work in the 1970’s, see K.J. McCree, The action spectrum, absorptance and quantum yield of photo-synthesis in crop 300382/ plants. Agric Meteorol, Vol. 9, pp. 191-216 (1972), has established the efficiency in which plants utilize different parts of the spectrum, and established the “McCree curve” which shows the internal quantum efficiency used by plants, in the wavelength at the range of 300 to 800 nm.

Whereas the photosynthetically active region (PAR) of sunlight is defined in the range of 400-7nm, plants also utilize some light outside of this range (below 400nm and above 700nm). In addition, although chlorophyll, the main pigment involved in photosynthesis, has its absorption peaks in the red and blue parts of the spectrum, plants are able to absorb and also require the entire spectrum (including yellow and green light) for other processes.

Plants also have very particular requirements for light dose in various stages of growth. However, most plants do not require the full intensity of sunlight even during their most demanding growth stages. In fact, plants have internal mechanisms to protect itself from higher than required light intensities (causing light stress). The required photosynthetic photon flux density (PPFD - the amount of PAR photons reaching the plant per area and time) is 50-60% of the sun’s intensity.

The objective of the present invention is a selective spectral absorbance and transmittance solar cell, which can be deployed over the entire area used for agricultural purposes while maintaining the ideal light spectrum and intensity required for the plants. By comparing the sun’s spectrum with McCree’s curve, also considering PPFD, or intensity, by the difference between those curves, it is evident that there are significant parts of the spectrum (both in wavelength and intensity) that can be utilized for photovoltaic energy conversion, without preventing any of the light required for healthy plant growth.

It is in the scope of the invention wherein the spectral transmittance required for the plants (in red) and the supplemental spectral absorptance (plus any reflectance) that the photovoltaic cells must exhibit (in green) in order to allow the required amount of sunlight to reach the plants underneath.

We exploit herein two types of solar cells exhibiting specific tailored spectral tunability - namely quantum dots and perovskite solar cells, and fabricate a tandem solar cell with several layers whose total absorptance (and reflectance) matches the required one. This tunability can be achieved by composition selection and the production process conditions; the type and size of quantum dots govern their absorption spectrum, the additives used in perovskites based solar cells achieve the same goal. 300382/ Furthermore, this tunability can be exploited to match not only the general McCree curve, but a curve which is tailored specifically to match a particular plant type’s spectral requirement in order to optimize both energy use and plant growth simultaneously.

Another issue that is important to address is the toxicity of the raw materials used to fabricate the solar cells. Whether it is the end-of-life (dismounting, recycling) of the modules or during normal operation, it is very desirable to use raw materials that are non-toxic to biological lifeforms (both flora and fauna, land or marine), such as lead (Pb), Arsenic (As) etc. which are known to be poisonous and dangerous even at very low levels of exposure.

SUMMARY OF THE INVENTION It is hence one object of the present invention to disclose a “tandem” structure of Perovskite and Quantum dots, in multilayer structure, characterized by that each layer is accepting specific wavelength range, and transmitting either or both (i) part of the range, and (ii) all the other wavelengths. The wavelength range of each layer is dictated by its composition, particle size, and particle concentration. Another object of the present invention to disclose a tandem selective spectral absorbance and transmittance solar cell, comprising a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, whose total transmittance is tailored to match plants’ required absorption (light intensity vs. wavelength); further comprising mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated; wherein the solar cell light absorption in different wavelengths is tuned by using wavelength-tunable different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; wherein the solar cell transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelength ranges; (b) concentration of absorption centers (which affects the transmittance of light in the wavelength region absorbed by the absorption centers); (c) thickness of the wavelength-specific active layer in the cell (determining the amount of light absorbed/transmitted over other layers in the solar cell.

It is another object of the present invention to disclose a tandem selective spectral absorbance and transmittance solar cell as defined above, wherein absorptance/transmittance properties of the solar cell are tailored not to transmittance curve general to all plants (the McCree curve) and a 300382/ “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity) It is another object of the present invention to disclose a tandem selective spectral absorbance and transmittance solar cell, as defined in any of the above, wherein materials comprising the solar cells are non-toxic to biological lifeforms, e.g. not containing heavy-metals, including those selected from a group consisting of lead (Pb), chromium (Cr), and Antimony (Sb).

It is another object of the present invention to disclose a method of manufacturing a method of manufacturing a “tandem” selective spectral absorbance and transmittance solar cell, comprising steps of providing multilayer structures of Perovskite and Quantum dots, each layer is accepting specific wavelength range, and transmitting either or both (i) part of the range, and (ii) all the other wavelengths. The wavelength range of each layer is dictated by its composition, particle size, and particle concentration. Another object of the present invention to disclose a method of manufacturing a tandem selective spectral absorbance and transmittance solar cell, comprising steps of providing a plurality of n layers of absorbing materials ,n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell.

It is another object of the present invention to disclose the method as defined above, wherein the method comprising step of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity).It is another object of the present invention to disclose the method as defined above, wherein the method further comprising step of utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chrome (Cr), and Antimony (Sb).It is another object of the present 300382/ invention to disclose the method for utilizing a “tandem” selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic (solar) cells, , comprising steps of providing a plurality of n layers of absorbing materials ,n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell.

It is another object of the present invention to disclose the method as defined above, wherein the method further comprising step of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity).It is another object of the present invention to disclose the method as defined in any of the above, wherein the method further comprising step of utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chromium (Cr), and Antimony (Sb).

It is another object of the present invention to disclose a “tandem” structure of Perovskite and Quantum dots, in a multilayer structure, wherein each layer is accepting specific wavelength range, and transmitting either or both (i) at least a part of the range, and (ii) all the other wavelengths; wherein the system comprises a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, whose total transmittance is tailored to match plants’ required absorption (light intensity vs wavelength); further comprising mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated; wherein the solar cell light absorption in different wavelengths is tuned by using different semiconducting quantum-dots 300382/ and/or different wavelength-tunable perovskite-based absorption layers; wherein the solar cell transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelengths; (b) concentration of absorption centers (which affects the transmittance of light in the wavelength region absorbed by the absorption centers); and (c) thickness of the wavelength-specific active layer in the cell (determining the amount of light absorbed/transmitted vs other layers in the solar cell; and wherein absorptance/transmittance properties of the solar cell are tailored not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity); and further wherein materials comprising the solar cells are non-toxic to biological lifeforms, and not containing heavy-metals, including those selected from a group consisting of lead (Pb), chrome (Cr), and Antimony (Sb).

It is another object of the present invention to disclose a method of manufacturing a “tandem” selective spectral absorbance and transmittance solar cell, comprising steps of providing multilayer structures of Perovskite and Quantum dots, each layer is accepting specific wavelength range, and transmitting either or both (i) part of the range, and (ii) all the other wavelengths; further comprising steps of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell; further comprising step of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity); further 300382/ comprising step of utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chrome (Cr), and Antimony (Sb).

It is another object of the present invention to disclose a method of utilizing a “tandem” selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic (solar) cells, , comprising steps of providing a plurality of n layers of absorbing materials ,n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell.

It is another object of the present invention to disclose a method of utilizing a “tandem” selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic (solar) cells, , comprising steps of providing a plurality of n layers of absorbing materials ,n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers 300382/ in the solar cell; tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity) and utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chrome (Cr), and Antimony (Sb).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the various embodiments of the disclosure. Within the following description, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

The term " solar cell module " in the present invention means a structural body comprising a plurality of solar cells (photovoltaic elements) electrically connected with each other in series while being sealed by means of a sealing material including an organic sealing resin. The term " solar cell module string " means a string comprising a plurality of solar cell modules arranged while being electrically connected with each other in series. As used in some of the embodiments herein, the term “ solar cell ” refers to the component for converting solar energy into electrical energy. In some embodiments, the terms “ solar cell ” and “ battery sheet ” can be used interchangeably. In some embodiments, a solar cell is silicon-based. In some embodiments, a solar cell does not comprise silicon and instead comprises glass or plastic sheet.

In some embodiments the solar cell comprises composite solar materials, e.g., copper indium gallium selenide (CIGS), cadmium telluride (CdTe), gallium arsenide (GaAs). In some embodiments, a solar cell can comprise organic solar materials or polymer solar materials. In some embodiments, a solar cell can be a dye-sensitized solar cell. continuing goal is to reduce the cost, size and/or complexity of solar devices, while maintaining, and preferably improving, robustness of the devices. Accordingly, it is desired to develop improved solar cells. Although the term “ solar cell ” refers to “ solar ” and thus implies that it is configured to work with sunlight, 300382/ the term “ solar cell ” is utilized in the art to refer generically to devices which convert electromagnetic radiation from any source (sunlight or otherwise) to electrical energy. The term “ solar cell ” is utilized in some of the embodiments herein to refer to devices which convert electromagnetic radiation from any source into electrical energy, and is to be understood to be broad enough to include devices which convert light from regions of the electromagnetic spectrum outside of the wavelengths primarily associated with sunlight.

The term " solution " is used herein to refer to a mixture of a solid and a liquid. While in some embodiments, the term " solution " refers to a mixture wherein the solid is dissolved in the liquid, this term also encompasses a colloidal solution, or dispersion solution, where the solid particles are dispersed in the liquid.

The technology disclosed hereinafter relates with a “tandem” structure of selective spectral absorbance and transmittance solar cell comprises Perovskite and Quantum dots, in multilayer structure. The system, according to one set of embodiments, is at least partially transparent so that its transparency in a relevant ranges of wavelength ranges from about 5% to about 95% of the irradiated intensity. By way of example, the solar cell is transparent and is configured or translucent to transmit at least about 50%, or alternatively, at least 90%, or alternatively, at least 99% of the intensity, or alternatively, more than about 5%, or alternatively, more than 10%, or alternatively, more than 25% or alternatively, more than about 50%; wherein the term “about” refers to a value being greater or smaller than up to 20% of the defined measure.

Perovskite Solar Cell Parts As defined in US20200127204A1 and elsewhere, the term “ perovskite ,” as used herein, refers to a material having the general structural formula QZX3, wherein Q and Z are cations of different sizes and X is an anion. The skilled person will also appreciate a perovskite material could be represented by the formula [Q][Z][X] 3, wherein Q is at least one cation, Z is at least one cation and X is at least one anion. In some embodiments, the “Q” component of the material is selected from methylammonium CH3NH3 (MA), formamidinum CH(NH2)2 (FA), n-butylammonium, tetra-butylammonium C4H9NH3 (BA), and combinations thereof, the Z component is selected from a transition metal such as Pb, Sn, Cs, or combinations thereof; and the X component is selected from a halogen such as I, Cl, Br, and variants thereof. Additionally, or alternatively, in the case of an organometal halide, the Q site refers to an organic group, Z represents a metal such as lead or 300382/ cesium, and X is a halide group such as iodide, chloride, fluoride, or bromide. For example, suitable perovskite materials include, but are not limited to, materials selected from the group consisting of: MAPbI3, MAPbBr3, MAPbIxBr3−x, MAPbIxCl3−x, FAPbI3, FAPbBr3, FAPbIxBr3−x, FAPbIxCl3−x, BAPbI3, BAPbBr3, BAPbIxBr3−x, BAPbIxCl3−x, MASnI3, MASnBr3, MASnIxBr3−x, FASnI3, FASnBr3, FASnIxBr3−x, FASnIxCl3−x, BASnI3, BASnBr3, BASnIxBr3−x, BASnIxCl3−x, FAyCszMA1−y−x(I1−xBrx)3, and combinations and mixtures thereof. In some examples, the perovskite layer comprises CH3NH3PbI3 (MAPbI3). In some examples, the perovskite layer is prepared by a solution processing technique, such as spin coating or a roll-to-roll printing process. The perovskite layers can be derived from a perovskite material as described herein.

The perovskite layer can, for example, have an average thickness of 300 nm or more; e.g., 325 nm or more, 350 nm or more, 375 nm or more, 400 nm or more, 425 nm or more, 450 nm or more, 475 nm or more, 500 nm or more, 550 nm or more, 600 nm or more, 650 nm or more, 700 nm or more, 750 nm or more, 800 nm or more, 850 nm or more, or 900 nm or more. In some examples, the perovskite layer can have an average thickness of 1000 nm or less; e.g., 950 nm or less, 9nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 475 nm or less, 450 nm or less, 425 nm or less, 400 nm or less, 375 nm or less, or 350 nm or less. The average thickness of the perovskite layer can range from any of the minimum values described above to any of the maximum values described above For example, the perovskite layer can have an average thickness of from 300 nm to 1000 nm; e.g., from 300 nm to 650 nm from 650 nm to 1000 nm, from 300 nm to 400 nm, from 400 nm to 5nm, from 500 nm to 600 nm, from 600 nm to 700 nm, from 700 nm to 800 nm, from 800 nm to 900 nm, from 900 nm to 1000 nm, from 300 nm to 500 nm, or from 400 nm to 900 nm. The thickness of the perovskite layer can be determined by cross-sectional scanning electron microscopy.

Quantum Dots (QD) Solar Cells The term " quantum dots " is used herein to refer to a semiconductor crystal, which is typically several nanometers in size, such as from about 1 nm to about 100 nm.

Composition of QD suitable for agriculture The bandgaps of quantum dots are tunable across a wide range of energy levels and can be controlled by the quantum dot size. This is in contrast to bulk materials, where the bandgap is fixed by the choice of material composition. This property 300382/ makes quantum dots more attractive for multi junction solar cells, where a variety of energy levels can convert more power from the solar spectrum. Half of all the solar energy reaching the Earth is in the infrared, most of it in the near infrared region. With a quantum dot solar cell, IR-sensitive materials are just as easy to use as any other, opening the possibility of capturing much more energy cost-effectively. QD can be simply deposited on a transparent substrate through spin coating. In large-scale production, the deposition could be achieved by spray-on or roll-printing systems, which are relatively low-cost processes. The QD composition is non-toxic for humans, animals, and plants, in case of panel failure, or for panel preparation or recycling purposes. The QDs are composed of nano-crystals of heavy metal dispersed within a transparent panel of glass or plastic.

According to one set of embodiments, the composition of heavy metal is non-toxic and does not comprise cadmium, mercury, arsenic, or lead. A Cadmium free QD composition, for example, may comprise doped ZnS/ZnSe, graphene, silicon, and CsSnI3.

According to yet another set of embodiments, QD solution may comprise QD that are coated with octadecene, oleylamine, oleic acid, and/or surface-active agent/ligand(s).

According to another set of embodiments, QD solution may comprise liquid carrier such as ethanol, toluene, and hexane.

According to another set of embodiments, QD solution may comprise poly(vinyl alcohol) (e.g., PVA, Mw 100,000) which is useful as a coating agent for indium tinoxide (ITO) substrates and providing a planar texture.

According to another set of embodiments, core composition comprises a nano-crystal which comprises, e.g., zinc, aluminum, gallium, indium, thallium, silver, gold, copper, cobalt, iron, nickel, telluride, antimony, silicon, manganese, indium, selenium, sulfur and any combination thereof, including, inter alia, zinc sulfide, zinc oxide, zinc selenide, zinc telluride, aluminum nitride, aluminum sulfide, aluminum phosphide, aluminum antimonide, aluminum indium nitride, indium aluminum phosphide, aluminum gallium phosphide, aluminum indium gallium nitride, gallium nitride, gallium phosphide, gallium antimonide, indium nitride, indium phosphide, indium antimonide, indium gallium nitride, indium gallium phosphide, thallium nitride, thallium phosphide, thallium antimonide, silver indium selenide sulfide, silver indium selenide, gold indium selenide sulfide, gold indium sulfide, copper aluminum selenide sulfide, copper gallium 300382/ selenide sulfide, copper aluminum selenide, copper gallium selenide, copper indium selenide sulfide and any derivative and combination thereof.

According to another set of embodiments, QD solution may comprise a core and a shell as presented in the art, see e.g., US20190051779A1 “Colorless luminescent solar concentrators using colloidal semiconductor nanocrystals”.

According to another set of embodiments, a shell material is used to enhance core’s stability, to enable good dispersion on a matrix, and to improve the photo-luminescent intensity of the core nano-crystal.

According to another set of embodiments, QDs are characterized by their tunable band gap properties. Such a tuning is provided useful by altering QD’s particle size, and tuning metal chalcogenide composition by e.g., engineering particles’ stoichiometry.

QDs synthesis and defining their emission range It is in the scope of the invention wherein QDs are prepared and structured by any commercially available means and methods, including utilizing either or both the cation exchange and SILAR synthetic approaches. For both the issues of synthesis and defining emission range, reference is made to applicable methods disclosed by Adegoke, O., Park, E. Size-confined fixed-composition, and composition-dependent engineered band gap alloying induces different internal structures in L-cysteine-capped alloyed quaternary CdZnTeS quantum dots. Sci Rep 6, 27288 (2016); and Haiguang Zhao, Federico Rosei, Colloidal Quantum Dots for Solar Technologies, Chem, 3, 2,2017, Pages 229-258.

It is well in the scope of the invention wherein the aforesaid technology is applied in building elevated structures; e.g., suspended construction’s or otherwise assemblies that are provided above surface area; containing the compositions defined hereafter. The elevated structures are provided useful for installing photovoltaic cells, solar panels, and any other means to harvest sun electromagnetic radiation and heat thereof. Those selective spectral absorbance and transmittance panels provide both efficient and land-saving Agri-voltaic usages as defined below: Under and below the elevated structures there are lower surface(s) utilizable to other sun (light and warmth)-requiring uses, including human and animal habitats, agriculture, e.g., growing field crops, land vegetation, horticulture, aquaculture etc. 300382/ In i.e., in the scope of the invention wherein a “tandem” selective spectral absorbance and transmittance solar cell, comprising a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, e.g., 2, 6, or 20, whose total transmittance is tailored to match plants’ required absorption (light intensity vs wavelength) according to one embodiment of the present invention. At least one first elevated structure is carrying a photovoltaic cell (2) positioned above the ground where vegetation (4) is grown in a natural habitat comprising insects (5) etc. Sun (1) radiates electromagnetic spectra, some is utilized by the selective spectral absorbance and transmittance photovoltaic cell to produce energy, and some (3), e.g., spectra between the blue, green, and red (i.e., between about 400 to about 800 nm) utilizes for agricultural and urban purposes. In one embodiment of the invention, photovoltaic cell (2) further comprises mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated, i.e. grown or composed together on one substrate being electrically and mechanically connected within the solar cells (e.g. with transparent conducting oxide layers); and both (i) and (ii) - parts are mechanically separate and parts are monolithically integrated. The photovoltaic (solar) cell (2) absorb light in different wavelengths is tuned by using different at least partially conducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers. Cell (2) further transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelengths; (b) concentration of absorption centers (which affects the transmittance of light in the wavelength region absorbed by the absorption centers); (c) thickness of the wavelength-specific active layer in the cell (determining the amount of light absorbed/transmitted vs other layers in the solar cell.

It is in the scope of the invention wherein the elevated structure cover most of the area of the lower surface. Hence, according to one embodiment of the invention, the elevated structure covers up to about 51% of the lower surface. According to another embodiment of the invention, the elevated structure covers up to about 75% of the lower surface. According to another embodiment of the invention, the elevated structure covers up to about 95% of the lower surface. According to another embodiment of the invention, the elevated structure covers more than 95% of the lower surface.

It is in the scope of the invention provides the elevated structures useful for allowing both (a) rain drainage and (b) moisture evaporation. 300382/ It is also in the scope of the invention wherein at least one first elevated structure is located at a first height; and at least one second elevated structure is located at a second (higher) height. The at least one second (highest) structure cover at least one first portion of the at least one first (respectively lower) elevated structure, and both covers at least one second portion of the land (i.e., lowest surface).

It is also in the scope of the invention wherein a stack array comprises a plurality of elevated structures and a plurality of low-surfaces is provided. Hence a higher-most elevated structure of a first type of photovoltaic cell or solar system harvest sun’s at least one first energy spectrum. Under this is located a first agricultural producing system, e.g., aquaculture in transparent container. Under this located a lowermost elevated structure of a second type of photovoltaic cell or solar system harvest sun’s at least one second energy spectrum. Under this is located a second agricultural producing system, e.g., growing field crops.

New standard for combined usage for both agriculture and photovoltaic While ministries of agriculture are limiting the agrivoltaic land usage, ministries of energy are strongly supporting such a usage. The present invention hence discloses means and methods for a full photovoltaic usage, without any limitation to agriculture usage.

In one set of embodiments of the present invention, various compositions of PS, all of which are selective spectral absorbance and transmittance and thus suitable for use in agriculture, are disclosed. In yet another set of embodiments of the present invention, methods for making PS and QD for selective absorbance and transmittance, multi layers structure, are disclosed.

Various compositions of PS and QD of specific wavelengths, sizes and compositions are disclosed below: Lead containing perovskite have power conversion efficiency (PCE) above 25% in lab, poor lifetime (<2,000 hours) and strong impact on environment due to potential release of lead in a soluble form. Efforts have been made to fix these environmental challenges by looking for alternative element to Lead. One approach taken was to prevent the release of Lead degraded compounds by chemical sequestration. Another approach taken is improving the sealing of the module (mechanical improvement).

EXAMPLE 1 300382/ One aspect of the invention is hence the use of organometal halide perovskite with enhanced optical absorption in the red/IR range. CH3NH3PbX3 (X is a halogen atom) where Pb is replicable. Characteristic absorption peaks in perovskite are being tailored to most wavelengths of the visible spectrum by adjusting the metal atom (Ge, Sn, and Pb), halogen (Cl, Br, and I) and/or inorganic sheet thickness. Typical perovskite CH3NH3PbI3 exhibits a steep absorption onset at 825 nm (1.eV) with a large absorbance coefficient of about 5.5 cm-1. Pb perovskites composed of (CH3NH3+) or (HC(NH2)2+ cations and iodide (anion) emit between 700 and 800 nm while the emission of similar Sn perovskites lies within 850–1000 nm, covering a broad region of the near-IR spectrum (photoluminescence).

Another aspect of the invention is use lead free organometal halide perovskite: Pb is replicable by Sn, Bi, Ge, Sb and Cu. It is disclosed herein that improving lifetime is utilizable by adding spacers in the crystal lattice: phenyl ethyl ammonium chloride (PEACl). Lead free organometal halide perovskite is utilizable with a bandgap of below 1.48 eV. Lead Free perovskite utilizable for agrivoltaic solar cell is (CH3NH3)3Bi2I9, Cs2SnI6, methylammonium tin iodide (MASnI 3), formamidinium tin iodide (FASnI3), cesium tin iodide (CsSnI3), bandgaps around 1.2-1.4 eV for lead-based perovskite, bandgaps of around 1.1 to 2.5 eV for lead free.

Hence, a “tandem” structure of Perovskite and Quantum dots, in a multilayer structure is provided useful. Each layer is accepting specific wavelength range, and transmitting either or both (i) at least a part of the range, and (ii) all the other wavelengths. In one embodiment provided useful, the system comprises a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, whose total transmittance is tailored to match plants’ required absorption (light intensity vs wavelength); further comprising mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated.

In another embodiment provided useful, the solar cell light absorption in different wavelengths is tuned by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers.

In another embodiment provided useful, the solar cell transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelengths; (b) concentration of absorption centers (which affects the transmittance of 300382/ light in the wavelength region absorbed by the absorption centers); and (c) thickness of the wavelength-specific active layer in the cell (determining the amount of light absorbed/transmitted vs other layers in the solar cell.

In another embodiment provided useful, the absorptance/transmittance properties of the solar cell are tailored not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity).

In another embodiment provided useful, the materials comprising the solar cells are non-toxic to biological lifeforms, and not containing heavy-metals, including those selected from a group consisting of lead (Pb), chrome (Cr), and Antimony (Sb).

EXAMPLE 2 Another aspect of the invention, namely a method of manufacturing a “tandem” selective spectral absorbance and transmittance solar cell, was provided utilizable by comprising steps of providing multilayer structures of Perovskite and Quantum dots, each layer is accepting specific wavelength range, and transmitting either or both (i) part of the range, and (ii) all the other wavelengths.

In another embodiment provided useful, the method further comprises step(s) of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell. 300382/ In another embodiment provided useful, the method further comprises step(s) of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity).

In another embodiment provided useful, the method further comprises step(s) of utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chrome (Cr), and Antimony (Sb).

EXAMPLE Another aspect of the invention, namely a method of utilizing a “tandem” selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic (solar) cells, was found utilizable.

The method comprises steps of providing a plurality of n layers of absorbing materials ,n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption (light intensity vs wavelength); providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning the solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining the solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by the absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell; tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants (the McCree curve) and a “synthetic” solar spectrum, but to a specific type of plant, at a specific physical latitude (sun orientation and intensity) and utilizing non-toxic to biological lifeforms materials for the solar cells; the materials are free of lead (Pb), chrome (Cr), and Antimony (Sb). 300382/ The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (8)

300382/ CLAIMS What is claimed:

1. A tandem structure of Perovskite and Quantum dots, in a multilayer structure, characterized by that each layer is accepting specific wavelength range, and transmitting either or both (i) at least a part of said range, and (ii) all the other wavelengths; wherein said system comprises a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, whose total transmittance is tailored to match plants’ required absorption; further comprising mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated; wherein said solar cell light absorption in different wavelengths is tuned by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; wherein said solar cell transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelengths; (b) concentration of absorption centers; and (c) thickness of the wavelength-specific active layer in the cell.

2. A method of manufacturing a tandem selective spectral absorbance and transmittance solar cell, comprising steps of providing multilayer structures of Perovskite and Quantum dots, each layer is accepting specific wavelength range, and transmitting either or both (i) part of said range, and (ii) all the other wavelengths, said method comprising steps of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption; providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning said solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining said solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by said absorption centers; and (c) defining thickness of the wavelength-specific active layer 300382/ in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell.

3. A method of utilizing a tandem selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic cells, comprising steps of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption; providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning said solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining said solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by said absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell.

4. The method of claim 3, comprising step of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants and a synthetic solar spectrum, but to a specific type of plant, at a specific physical latitude.

5. The method according to any one of claim 3 or 4, further comprising step of utilizing non-toxic to biological lifeforms materials for said solar cells; said materials are free of lead, chrome, and antimony. 300382/

6. A tandem structure of Perovskite and Quantum dots, in a multilayer structure, wherein each layer is accepting specific wavelength range, and transmitting either or both (i) at least a part of said range, and (ii) all the other wavelengths; wherein said system comprises a plurality of n layers of absorbing materials, n is integer being equal or greater than 1, whose total transmittance is tailored to match plants’ required absorption; further comprising mechanically separate selective spectral absorbance and transmittance thin film solar cells, whose electrical contacts are connected outside the cells’ active area, monolithically integrated; wherein said solar cell light absorption in different wavelengths is tuned by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; wherein said solar cell transmittance in different wavelength is determined by one or more members of a group consisting of (a) type of layers used, absorbing different wavelengths; (b) concentration of absorption centers; and (c) thickness of the wavelength-specific active layer in the cell; and wherein absorptance/transmittance properties of the solar cell are tailored not to transmittance curve general to all plants and a synthetic solar spectrum, but to a specific type of plant, at a specific physical latitude; and further wherein materials comprising the solar cells are non-toxic to biological lifeforms, and not containing heavy-metals, including those selected from a group consisting of lead, chrome, and antimony.

7. A method of manufacturing a tandem selective spectral absorbance and transmittance solar cell, comprising steps of providing multilayer structures of Perovskite and Quantum dots, each layer is accepting specific wavelength range, and transmitting either or both (i) part of said range, and (ii) all the other wavelengths; further comprising steps of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption; providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning said solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining said solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption 300382/ centers, thereby affecting the transmittance of light in the wavelength region absorbed by said absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell; further comprising step of tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants and a synthetic solar spectrum, but to a specific type of plant, at a specific physical latitude; further comprising step of utilizing non-toxic to biological lifeforms materials for said solar cells; said materials are free of lead, chrome, and antimony.

8. A method of utilizing a tandem selective spectral absorbance and transmittance solar cell for growing agricultural products under photovoltaic cells, comprising steps of providing a plurality of n layers of absorbing materials, n is integer being equal or greater than 1; tailoring their total transmittance to match plants’ required absorption; providing mechanically separate selective spectral absorbance and transmittance thin film solar cells, and connecting electrical contacts outside cells’ active area, so that they are monolithically integrated; tuning said solar cell light absorption in different wavelengths by using different semiconducting quantum-dots and/or different wavelength-tunable perovskite-based absorption layers; determining said solar cell transmittance in different wavelength by one or more members of a group consisting of (a) utilizing various type of layers, thereby absorbing different wavelengths; (b) utilizing definable concentrations of absorption centers, thereby affecting the transmittance of light in the wavelength region absorbed by said absorption centers; and (c) defining thickness of the wavelength-specific active layer in the cell hence determining the amount of light absorbed/transmitted vs other layers in the solar cell; tailoring absorptance/transmittance properties of the solar cell not to transmittance curve general to all plants and a synthetic solar spectrum, but to a specific type of plant, at a specific physical latitude and utilizing non-toxic to biological lifeforms materials for said solar cells; said materials are free of lead, chrome, and antimony.