EP2873099A1

EP2873099A1 - Optically active coating for improving the yield of photosolar conversion

Info

Publication number: EP2873099A1
Application number: EP13744756.1A
Authority: EP
Inventors: Marc Schiffmann; François LE POULL; Philippe Gravisse
Original assignee: Cascade SAS; Laboratoire De Physique Du Rayonnement Et de la Lumiere
Current assignee: CASCADE; LABORATOIRE DE PHYSIQUE DU RAYONNEMENT ET de la LU
Priority date: 2012-07-16
Filing date: 2013-07-16
Publication date: 2015-05-20
Also published as: WO2014013186A1; US20150270427A1; US9520521B2; FR2993409A1; FR2993409B1

Abstract

The invention relates to optically active coatings for improving the yield of photosolar conversion, consisting of a transparent matrix containing a plurality of optically active constituents absorbing the light energy in a first absorption wavelength lambdaA1 and reemitting the energy in a second wavelength lambdaR1 different from lambdaA1, said optically active constituents being selected such that the reemission wavelength lamdaR1 of at least one type of constituent corresponds to the absorption wavelength lambda_A2 of at least one second type of constituent, characterised in that the C₂/C₁ ratio of concentration C₁ of the optically active constituents of a first type in relation to the concentration C₂of the optically active constituents of said second type is between 0.13 and 0.26; C_i designating the concentration in moles per litre of the constituent i in relation to the doped matrix.

Description

Optically active coating for improving photosolar conversion efficiency

Field of the invention

The present invention relates to the field of photosolar conversion, and more precisely 1 optimization of this conversion to improve the photoconversion efficiency of films or plates interposed between the solar radiation and equipment such as a greenhouse, a phytoreactor or a photovoltaic cell.

It relates more particularly to the implementation of a doped interface with optically active constituents forming a light cascade.

For the purposes of this patent, the term "light cascade" will be understood to mean the wavelength transfer occurring by the combination of a series of optically active constituents chosen so that the wavelength of re-emission of one type of constituent corresponds to the absorption wavelength of another type of constituent, each of the constituent types being defined by a retransmission wavelength different from the absorption wavelength. These constituents are of the photoluminescent type, scintillators, fluorescent, or laser dyes.

[0004] The "light cascade" within the meaning of this patent may also incorporate one or more molecules producing an anti-Stokes displacement (the atom of the molecule thus emits a photon of energy equal to the sum of the energy of the absorbed photon and phonon, so the wavelength of the emitted photon is shorter). In the inelastic collision between a molecule and a photon, a radiation of wavelength shorter than that which allowed the excitation is emitted. Stokes displacement is the difference in energy between the exciter wavelength and that, which is greater, therefore, of smaller energy than the emitted light. The molecule thus conserving an excess of energy which can be the source of the emission of a longer wavelength than that received (with a second photon). Displacement to smaller wavelengths (hence higher energy) than incident light may occur. Such a displacement is called anti-Stokes.

State of the art

It is known in the prior art French patent FR2792460 describing a photovoltaic generator comprising at least one photovoltaic cell and a transparent matrix deposited with at least one optically active material having a lambda absorption wavelength, and a length of lambda retransmission wave _{r /} the optically active material being selected such that lambda., corresponds to a range of lesser sensitivity of the photovoltaic cell as lambda _r, the matrix having a reflective coating. The matrix present on the input surface a dichroic filter substantially reflecting wavelengths longer than about 950 nm, and substantially transparent to wavelengths, wavelengths below 950 nm, and the surface opposite to the surface of ^one input a reflective coating for wavelengths longer than 400 nm, the photovoltaic cell being included in the transparent matrix.

[0006] US Pat. No. 4,088,508 describes an energy amplifier device adaptable to a solar cell, comprising a matrix inside which fluorescent substances are dispersed.

It is also known from US Pat. No. 4,367,367 describing a collector adapted to concentrate solar energy on a photoelectric cell, comprising in combination at least one glass plate doped with a fluorescent substance when illuminated by sunlight. A photocell is attached to one side side of the plate, the other lateral edges of the plate being provided with a reflective coating. The cell has a high efficiency in the wavelength range of the fluorescent radiation. A plurality of such glass plates may be stacked on top of each other, each doped to absorb at a predetermined region of the spectrum and to emit fluorescence in a region where a photocell is substantially sensitive. A fluorescent dye in a suitable substrate can be applied as a surface layer to such glass plates, which improves the overall efficiency of the collector.

[0008] US Pat. No. 4,110,0123 describes a photovoltaic converter, in which light is collected in a light concentrator comprising a transparent layer, the refractive index is greater than that of the ambient medium and which contains the fluorescent centers and is made to a solar cell, characterized in that more than one solar cell concentrator / combination is stacked on top of each other through a medium having a lower refractive coefficient than that of the concentrator, each concentrator being adapted to convert part of the incident spectrum into fluorescent light and supply it to a solar cell.

[0009] US Pat. No. 754,157 discloses a photovoltaic cell having improved conversion properties. The cell includes a cover for a photovoltaic device. In one embodiment, the cover includes a fluorescent material that shifts the wavelength of a portion of the incident light to be closer to the wavelength that produces the least thermal load on the photovoltaic device. In another embodiment, the cover comprises a fluorescent material between two reflecting filters. The cell and the lid can be placed together in a stack or separated together

Disadvantages of the previous ar

The solutions of the prior art have problems of optical efficiency. When the matrix contains several dopants of different natures, their chemical and optical interactions cause an attenuation or an alteration of the transmission in certain cases of high concentration of dopants, or a loss of efficiency when the concentration of certain dopants is insufficient.

An inappropriate concentration may even cause the extinction of some retransmission phenomena, thus completely changing the illumination spectrum produced by the doped interface.

Furthermore, certain solutions of the prior art provide a multilayer interface formed by a stack of planes each having a dopant of a particular type.

The disadvantage of these solutions is that the interactions are sequential and does not allow to create sufficient interactions for a real effect of optimization of the lighting spectrum.

[00014]

Solution provided by the invention

[00015] In order to overcome the drawbacks of the prior art, the invention relates, according to its most general meaning, to an optically active coating for improving the photosolar conversion efficiency, in accordance with the main claim.

It is for example constituted by a transparent matrix containing a plurality of optically active constituents absorbing light energy in a first lambda _A1 absorption wavelength and retransmitting the energy in a second lambda wavelength _R1 different from lambda _A1 , said optically active constituents being chosen so that the lambda retransmission wavelength _R1 of at least one type of constituent corresponds to the length of lambda. _A2 lambda absorption wave of at least a second type of constituents _/ characterized in that the ratio between concentration of the optically active components of a first type with respect to the concentration C ₂ of the optically active components of said second type is between 0.4 and 0.6; C _t designating the concentration in moles per liter of the component i with respect to the doped matrix.

The invention relates in particular to an optically active coating for improving the photosolar efficiency for the optimization of the efficiency of a photovoltaic cell, characterized in that it comprises N types of constituents C0A _stored where the wavelength retransmission rate is less than the absorption wavelength, where N is equal to 3 or 5, the concentration C _n of the rank N constituents being between 0.4N and 0.6N, the matrix containing in addition a component C0A _anti8tockes where the wavelength of retransmission is smaller than the wavelength of absorbtion.

[00018] Preferably, the type of optically active constituents of the highest rank N has a retransmission wavelength whose peak is located between 945 nanometers and 980 nanometers.

According to a first variant, said matrix consists of a film of ethylene-vinyl acetate or poly methyl methacrylate.

According to a second variant, said matrix consists of a methyl methacrylate or silicone resin.

According to a third variant, said matrix is constituted by a polyvinyl chloride film.

According to another variant, said matrix consists of a film consisting of a copolymer comprising 80% and 90% low density polyethylene and 10% to 20% ethylene vinyl acetate.

According to another variant, said matrix consists of polyvinylidene fluoride.

The invention also relates to a photovoltaic module characterized in that it comprises at least one photovoltaic element associated with an optically active coating in accordance with one of the abovementioned coatings.

Advantageously, this module further comprises COA _{antlstockea components} where the retransmission wavelength is between 550 and 800 nanometers is less than the absorption wavelength is between 1000 and 1500 nanometers.

[00026] Advantageously, the module comprises a reflective rear face, the photovoltaic element being encapsulated in an optically doped matrix to form said coating.

According to a particular variant, the module according to the invention comprises a plurality of photovoltaic elements forming a matrix with an expansion between 0.25 and 0.75, the areas between said photovoltaic elements being transparent.

According to another variant, the matrix encapsulating the photovoltaic elements include remanent compounds making it possible to restore light in the absence of insolation.

The invention also relates to optically active granules for the production of coating, in particular films according to the invention, characterized in that they consist of a transparent matrix containing a plurality of optically active constituents absorbing 1 light energy. in a first absorption wavelength lambdaAl and re - emitting the energy in a second wavelength lambdaR1 greater than lambdaAl, said optically active components being selected so that the retransmission wavelength lambdaR1 from minus one Type 3. Consistency of the absorption wavelength of at least one second type of

C »CD.0, iS * ^" *ûf _* ^" t _* ¾ΰ¾ ^' ¾ ^' ¾ ^" tïr * ϋϋί

concentration C1 of the optically active components of a first type with respect to the concentration C2 of the optically active constituents of said second type is between 0.1 and 0.2; Ci denoting the concentration in moles per liter of component i with respect to the matrix of

The granules are advantageously produced from high-grade EVA type polymers or polyvinyl chloride (PVC) doped or polyvinylidene fluoride.

Detailed description of nonlimiting examples of embodiment

The invention will be better understood on reading the description which follows, with reference to the accompanying drawings in which:

FIG. 1 represents a sectional view of a doped matrix according to the invention

FIG. 2 represents a schematic view of the incident and outgoing spectrum of a doped material according to the invention;

Nonlimiting description of exemplary embodiments

[00032] FIG. 1 represents a sectional view of a doped interface according to the invention. It consists of a transparent matrix containing constituents opc [u. sTie ac fs x ^* e xen es Δ s _*

In the application example described, the interface is applied to the surface of a photovoltaic cell (2) of known type,

The matrix is constituted by a rigid or flexible organic material, or in the form of an applicable coating in the form of a resin.

The organic material is chosen in particular from; poly (methyl methacrylate) (PMMA)

polyethylene vinyl acetate (EVA),

Polyvinyl chloride (PVC)

polycarbonate (PC)

Methyl methacrylate (MMA)

Low density polyethylene (LDPE)

a methyl methacrylate or silicone resin

Polyvinylidene fluoride (PVDF).

The optically active dopants are chosen from: organic phosphors, (Stokes effect)

inorganic phosphors (anti-stokes and remanent effect)

the optically active molecules of the type scintillating organic crystals with N + 1, N + 2, N + 3, N + x nuclei φ anthracenic type,

perylene or derivatives, pentacene, or diphenyl type organic phosphors, carbazol stylbene or derivatives, chosen in such a way that the emission spectra of one correspond to the absorption spectra of the others.

This is to produce the electromagnetic frequency shift expected from the UV and the visible towards the near IR in order to mobilize in the range of greater sensitivity of the Photovoltaic Silicon cell for example, the maximum possible light energy. , the maximum of photons of λ between 620 and 990nm corresponding to an energy close to the gap of a cell c.Si np for example.

[00038] The perylene is a chemical compound having the formula C ₂₀ H ₂ or C ₃₂ H _1S eg. It is a polycyclic aromatic hydrocarbon presenting as a brown solid.

Perylene emits a blue or red fluorescence, which makes it a blue or red dopant for organic light emitting diodes, whether substituted or not. It is also an organic photoconductor. It exhibits an absorption maximum at 434 nm with a molar extinction coefficient of 38,500 M-lcm-1 at 435,75 nm, and is poorly soluble in Water (1.2 * 10-5 mmol / l), like all other polycyclic aromatic compounds.

All the carbon atoms of the perylene are hybridized sp2, which explains why the central ring is not represented as a fifth benzene ring (because then two carbon atoms would be hybridized sp and the molecule would lose some of its character aromatic and its fluorescent properties). The structure of perylene has been extensively studied by X-ray diffractometry.

Pentacene is a chemical compound of formula C22H14 belonging to the family of polycyclic aromatic hydrocarbons (PAHs) and formed from five benzene rings fused linearly. Its extensive conjugated structure and crystalline structure make it a good organic p-type semiconductor (electron donor). Excitons are formed by absorption of ultraviolet or visible radiation, which makes it very sensitive to oxidation: this is the reason why, when it has the appearance of a red powder when it is has just been synthesized, it turns little by little to green in the open air and in the light.

Pentacene is a promising material in the production of "thin-film transistors" type transistors and organic field effect transistors. The motility of the holes is 5.5 cm 2 · -l · s-1, almost at the level of the amorphous silicon. It forms p-n junctions with fullerene C60 used to produce organic photovoltaic cells

For the highest rank N component: 5,12-bis (phenylethynyl) naphthacene, also abbreviated as BPEN, is a polycyclic aromatic hydrocarbon of formula C34H20 used as a fluorochrome for chemiluminescent tubes; it emits an orange light. It is an organic n-type semiconductor.

The purpose of the system according to the invention is to mobilize at a silicon photocell, for example, mainly sensitive to light radiation between 700 and 950 nm, an incident energy higher than that normally provided by sunlight in this wavelength band.

In principle, the solar energy used is defined by the area of overlap of the emission spectra of sunlight and absorption of the solar cell.

Given the specificity of the cell (absorption of energy photons corresponding to wavelengths between 700 and 950 nm) and the fact that the energy recovered by the photocell is a function of solar irradiance , that is to say, the number of photons transported, one of the ways to increase the efficiency of the battery is to make usable photons of the part of the solar spectrum below 700 nm UV to the visible).

The process used transforms high-frequency photons (250 to 700 nm) into low-frequency photons (700 - 950 nm) by using the fluorescent properties of certain chemical compounds that are used as intermediates in the transport of energy from light. solar. The substances are chosen so that their absorption spectra constitute successive zones, making it possible to cover the entire solar spectrum in the zone (250-700 nm) (frequency or wavelength overlap). A luminous radiation of determined wavelength λ p could be absorbed by the substance whose absorption spectrum comprises this value of λ. The hvn or hc / In photons that allowed to excite the molecules of this substance (absorption phenomenon) are thus definitively extracted from the incident beam. But the unstable state that has been conferred on the molecules is of very short duration. The return to the ground state (stable state of the molecules at a given temperature) can be carried out in part (statistical expression of the phenomenon and advantageously in our case, by a radiative emission (fluorescence / phosphorescence). thus generated correspond to the absorption spectrum of another substance that will take over. It will be noted that a given substance will be able to absorb either the emission of the substance which precedes it in the sequence of products used (transformed energy), or the part of the emission of the corresponding solar spectrum (non-transformed energy).

[00048] At the level of the battery, the total usable energy can be expressed:

E _S0¾ = E _NÎ Σ ΣE _T With:

E _NT : Unprocessed energy (700-800nm zone of the solar spectrum) ¾ _γ : Σ transformation energies

With:

Α, Β, Ο, and D: Substances whose respective spectra share the solar spectrum in the increasing direction of the wavelengths

: Energy that has undergone all stages of transformation

: Energy from the radiation transformation of the visible range of the solar source located just below the sensitivity zone of the solar cell via the single substance D

The chemical compounds are trapped in a suitable matrix. The matrix will have to be applied on the battery so as to constitute a photon transformer, intermediate between the battery and the light source.

The different types of chemical compounds are dispersed in the matrix homogeneously.

The emission of chemical intermediates occurring in all directions, the emission of A (for example) is captured by molecules B located either between A and the cell, or between A and the source, ( and so on) .

The low frequency photons finally produced per unit of time go half toward the stack and half in the opposite direction (the photons emitted in a plane parallel to the stack being negligible). The chemical substances used will have high quantum fluorescence (or phosphorescence) yields and must not give rise to photochemical processes that are susceptible for altering the nature (and hence efficiency) of the photon transformer.

By way of example, the table below represents various examples of formulas and their composition and the concentration of the optically active constituents in a PMMA plate with a thickness of three millimeters (in gr / kg and in mole / liter) :

PPO Compound Uviiex OB 3G L V 850 L F R 305 GG s 2,5dlphen 2,5t iophene Hosasiol Perylene // OR 610 Hostasol

~> C26H26N20 NaphtaHmi Tetra. carbox Dl Red

Oxazole 2S d. Perylene C23H120

Reference C15H11N C24H802 C32H16 S e 0

0.44gr Q, llgr 0.06gr

Formula "Lj! I? 2 JL0 ™ 3 1,95 * 10-4

1 mole / liter mole / liter 5

mole / 1 itr e

0.44gr 0, Hgr 0.06gr 0.006gr

Formula 1.52 * 10-3 1.95 * 10-4 1.31 * 10-4 9.28 * 10-

2 moles / liter mole / liter mole / liter 6

mole / 1 itr e

G, 22gr 0.1 Igr Q, 06gr Q, 03gr

Formula 2.86 * 10-4 1.71 * 10-4 8.34 * 10-5

3 mole / liter mole / liter mole / liter mole / liter 0.22gr 0, 11gr 0.022395

Formula 3,40 * 10-4 gr

4 mole / liter mole / liter 8.0 * 10-5

mol / liter

0,22gr Q, llgr 0,03gr

Formula 1,11 * 10-3 2,86 * 10-4 8,34 * 10-5

5 mole / liter mol / liter moie / h ^'be

[00055] Table below shows various examples of formulas and composition and concentration of optically active constituents in a film ^f encapsulation EVA having a thickness of e 900μπι (in gr / kg mol / liter);

Com o PPG Uviiex OB 3G L V 850 L F R 305 RH800 Styry! 20 ses 2,5diphé 2,5thiophè Hostasol Perylene // OR 610 C26H26 C33H370

-> nyl ne Naphtafi Tetra.carbo diPeryfen M305, SSCI

Oxazole C26H26 2 mid xy. e

Referred C15H11 02S C24H802 C32H16

NO

0,88gr

Formu! 1.66 * 10 2, 14 * 10-4

e 6 -3 Mole / liter

mol / fitr

e

0.3 Igr 0.16gr 0.03gr

Formula 1.32 * 10 3.49 * 10-4 7.04 * 10- e 7 -3 mole / Be 5

mole / liter mole / liter

ee 0.88gr 0.22gr 0.025gr 0.0002

Formula 1.66 * 10 2, 14 * 10-4 2,61 * 10- 5gr

e 8 -3 mol / liter 5 2.09 * 1

mole / liter mole / liter 0-7

e e mole / bed

re

0.88gr 0.22gr 0.025gr 0.00025gr

Formula 1.66 * 10 2, 14 * 10-4 2.61 * 10- 1.75 * 10-7 e 9 -3 mole / liter 5 mole / liter mole / liter mole / liter

e e

In the examples given above, the optically active granules of 1 to 2 mm in diameter consist of optically active molecules (MOAs) integrated directly into different polymers of PMMA, EVA, PVC, PE types. They make it possible to realize coatings, films of displacement of luminous cascade (CL) for the various agricultural and photovoltaic applications.

However, some of the materials degrade and lose their optoelectronic features such as light cascades following the actions of photo-oxidation, hydrolysis, migrations of MOAs. This phenomenon appears in some of the polymer matrices such as polyolefins PE / E A or EVA specifically used for the production of agricultural films or 1 encapsulation of PV cells.

In order to reinforce the light fastness of the light cascades doped matrixes (CL), the MOAs are included in a medium compatible with them, such as PMMA, in which the optoelectronic characteristics of the MOAs / CLs are perennial.

The doped PMMA CL is micronized or pulverulent by a cryomilling technique and brought to the dimensions of a few tens of microns to use it as a stable organic pigment containing all or part of the useful MOAs.

This PMMA matrix is mixed in the EVA granules at the time of extrusion of the film. The 2013E formula is then given as an example. The concentration level of powdered PMMA is 10%. The particle size of the doped PMMA powder is 2 microns and the dopant concentration is 5 grams / kg of CL PMMA premix. For 5kg OMMA doped OMMA compound 25grs of distributed dopants:

PPO: 0, 44 ie 73.6% by weight of the doping formula

OB: 0.11, ie 18.3% by weight of the doping formula

GG: 0.0479, ie 8.1% by weight of the doping formula

For the production of photovoltaic modules, the matrix located beneath the cells on the face opposite to that of the photon collection, may advantageously be constituted by ethyl vinyl acetate, for example encapsulating the photovoltaic cells (cells) and rendered reflective by inclusion. of TiOx pigments

Also the matrix located below the cells and encapsulating the photovoltaic elements can be made reflective and remanent both according to an exemplary embodiment, by the inclusion (doping) of residual compounds such as Cu-doped ZnS inorganic crystals for example to restore the light in darkness for a long time> one hour, for example after the interruption of the incident electromagnetic energy (light excitation)

Similarly, the matrix beneath the cells encapsulating the photovoltaic elements can also be made anti-Stokes by the inclusion of Reidel-de Haën Green UC2 rare earth oxysulfide particles or RP YF3YbEr.

Similarly, the back substrate (or backsheet) of the photovoltaic module may consist of a polyfluorinated polymer such as polyvinylidene fluoride (PVDF) doped as the encapsulation matrix located beneath the cells with Ti02, and / or ZnS: Cu, and / or Green UC2 rare earth oxysulfide to confer the complementary functions of Reflectance and / or Remanence and or anti-Stokes in bands of length d wave complementary to those of the encapsulation matrices of the front side doped Stokes type light cascades.

In addition, the diffusing matrices amplified the efficiency and the efficiency of the light cascades. Preferably, the light cascades are associated with diffusing charges, Si0 ₂ , Si0 ₃ , zeolite alumino silicate, mesoporous silica. It should be noted that EVA films are also interesting because of their intrinsic diffusion coefficient. The mesoporous materials have a contact surface of the order of 1000 m ² / Gr / cm ^-1 are good candidates for the grafting of optically active molecules (MOA) / light cascades (CL), their light fastness and their phyisco-chemical inertia. . The formulas RREFLEC 2010 A ', B' and C 'in Table 3 are of this technique.

In front, there is CL with MOAs short afterglow fluorophores 10 ^{~ 8} second, while year back, there are mixed CL MOAs and COAs (optically active crystals) long photoluminescence 10 ^"8 seconds. Certain COAs can thus re-emit blue photons of 450 nanometers by photoluminescence after excitation, as an example of the joint use of two complementary light cascades: The 2013E formula on the front panel and the RREFLEC 2010 B 'formula in Table 3 The effectiveness of this pair of films / encapsulation plate will be all the more important as the proliferation of photovoltaic cells (PV), which by module, the yield will be lower than 0.9. is to make the entire surface of the active module optoelectronically, even areas not covered with PV cells.

In CL-doped films / plates the action of diffusing elements such as TiO 2, SiO 2, ultra-fine or pyrogenic silica, associated The cii is interesting in that it is transparent in the visible and they take into account the photons re-emitted by the MOAs in 4Pi steradian to increase the useful path in the doped matrix.

© plus the xnorganx structure of the pyrogenic plant whose developed surface is of the order of 250 to 400 m ² / gr is a st st o r gr o m age of M0i¾s talrxnt egr at xo _* So we get a photovoltaic module which since has been st xstxu optxc usd 'aÎDSorptxon g of eitixssxon fe reflection of retentive materials for encapsulation which consists complement each other and contribute to 1' axtiel xor at xon of gaxns jphotoelectrxc ue of _$ cells 1 photovoltaic module efficiency improvement ·

C "" "Rector 2!, Opt xcjuem nt J ^ c t x £

Doping of the EVA Film below the Cells: Optically Active Reflector in gr / kg ep. 450 μm of EVA and / or doping of the PVDF substrate (Vinylidene PolyFluoride backsheet).

AAntiStok j TTiOx <0.6 κ ι l KN KNanoparticles

Ddiffusant

IREFLEC20 00,75 00,375 22 22

L2BRm / A

IREFLEC 1 0.5

! OIO A '

IREFLEC 1 0.5 1

Ï010 B *

IREFLEC 1 0.5 1

C1010

[00062] For the application to agricultural films, a stratification architecture with multi-layers is carried out. Specialized optical treatments are complementary in wavelength absorption and reissue from one layer to another.

Thus from a complete light cascade at 4 levels of UV to Rough or IR, the outer layer to the sun is doping UV to blue and the inner layer is doping emitting in the band 600 up to 700 nm. The outer layer is more particularly dedicated to the first frequency shift, which also acts as a UV protection.

This technique is new by the coextrusion technique, simultaneous films of different qualities by the same machine. It adapts to coextruded agricultural films composed of a 600-700 nanometer doped central core otherwise treated with thermal or diffusing and the active outer layer in 400 up to 500 nanometer also treated with antioxidant or hydrophobic.

The choice of films are suitable for searching for conjugated or complementary optoelectronic effects favorable to the growth of the plants and / or to the optical functions of insect polinators.

[00066] The formulas below are adapted to the use of agricultural films for market garden plants, central core and outer layer. CL materials consisting of 2 specialized layers for tomatoes and cucumbers market gardening. The central core ¹ is the film in 80 micron, while the outer layer is 60 micrometer. The film used is 4TT.

A series of complete formulas will be used to boost the central core of the film in 80 μm (formulas P012 to P0015), in these films the dosage of the OB has been divided by 2 (formulas P012) and by 4 ( formula P013) to decrease see remove the disruptive effects vis-à-vis doping insect pollinators, for partial formulas l ^f central core is doped with either GG (P017 formula with either LRF305 (formula 018), the formula P016 is a doping with a mix GG / LRF305.

For the outer layer of the partially doped films, the dosing of the films with complete doping for the PPO and the QB of the formulas P0012 and 013 is repeated, but with concentrations brought back to values corresponding to βθμιιι films,

The rule of variation of MOAs concentrations as a function of the thickness of the films or plates of the materials doped CL. The notion developed here is that of the MOA / COA active population per unit area / number of incident photons. The Beer-Lambert law applies here to regulate the concentration of useful MOAs / COAs. This law is directly related to the physical parameters; it is independent of the number of incident photons which is another parameter of "smart" materials type OPTO CL.

[00070] According to Beer Lambert's law:

With:

D ^™ log ~ Σ * c * d D: Optical density

Σ: molar extinction coefficient

c: Molar concentration

d: Length of the trip

l ₀ light intensity at the entrance

I: Luminous intensity at the exit

Efficiency of absorption Siy = ^ - (-90% absorption - → log log 10 = 1)

If it? ^ _9g% absorption → log ^ ⁰ - ⁰ - ^ log 100 = 2)

Dependent only on the substance at a

D1 = 1 = Σ d, given wavelength = Cst from where to pass

D1 = 2 = Σ ¾ d ₂ from 10% to 1% just have ^ = 2

c ₂ d ₂

For example, doubling the concentration for a constant thickness or doubling the thickness at constant concentration

If Σ coefficient is uniform in the entire spectral range (200nm - 700nm). _F concentration must be about 2 * 10 ^"3 mol / liter These conditions are ideal for a given substance in the following case.

- diluted solution 99% absorption (absorption efficiency)

Dilute solution must have good conditions to have absorptions undisturbed by molecular associations.

When we have n substances to mix: it is necessary to multiply d by n (thickness of the matrix) to have an ideal concentration.

Example:

n = 4

d = 4 * 0.1

d = 0.4

[00071] The other concentration rule to be highlighted is that of the relative number of MOA1 / MOA2 / MOA3 / MOA4 / MOA n-1 with respect to each other. This concentration varies from one molecule to another depending on its molecular weight. To resume the model of the initial sequence of MOA PAH type benzenic their concentrations vary in 10-3, 10-4, 10-5 .... Depending on the molecular weight of each MOA, their number of aromatic nuclei: Anthracene 3phi (10-3) + Naphthalene 4phi (10-4) + pentacene 5phi (10-5) ...

Claims

claims

1 - Optically active coating for improving the photosolar conversion efficiency, constituted by a transparent matrix containing a plurality of optically active components absorbing light energy in a first absorption wavelength λambda _A1 and retransmitting the energy in FIG. a second lambda wavelength _R1 different from lambda _A1 , said optically active constituents being chosen such that the retransmission wavelength lambdaR1 of at least one type of constituent corresponds to the wavelength of absorption _A2 lambda of at least a second type of constituents, characterized in that the ratio C ₂ / C ₁ between concentration C _t of the optically active constituents of a first type with respect to the concentration C ₂ of the optically active constituents of said second type is between 0.13 and 0.26; Ci denoting the concentration in moles per liter of component i relative to the doped matrix.

2 - optically active coating according to claim 1 characterized in that the ratio C ₂ ^ ^c i between the concentration C _y of the optically active components of a first type with respect to the C ₂ concentration of the optically active constituents of said second type is between 0, 13 and 0, 26; C _L designating the concentration in moles per liter of the constituent i relative to the doped matrix, said matrix is constituted by an organic material selected from an ethylene-vinyl acetate film, a polyvinyl chloride film and a film constituted by a copolymer comprising 80% and 90% low density polyethylene and 10% to 20% ethylene vinyl acetate.

3. Optically active coating for the improvement of the photosolar efficiency for the optimization of the efficiency of a photovoltaic cell according to claim 1, characterized in that it comprises N types of stock constituents designated by the abbreviation C0A _etocke8 where the length of d reissue wave is higher than the absorption wavelength, where N is equal to 3 or 5, the concentration C n of the constituents of rank N being between 0.4N and 0.6N, the matrix containing in addition an anti- The invention is characterized in that the abbreviation C0A has a _value of less than the absorption wavelength.

4 - Optically active coating for the improvement of the photosolar efficiency for the optimization of the efficiency of a photovoltaic cell according to claim 1 or 2, characterized in that the type of optically active constituents of the highest rank N has a length of reissue wave whose peak is between 945 nanometers and 980 nanometers.

5 - Optically active coating for the improvement of the photosolar yield according to any one of the preceding claims, characterized in that said matrix consists of a film of ethylene-vinyl acetate or poly methyl methacrylate.

6 - Optically active coating for the improvement of the photosolar yield according to any one of the preceding claims, characterized in that said matrix consists of a methyl methacrylate or silicone resin.

7 - optically active coating for improving the photosolar efficiency according to any one of the preceding claims, characterized in that said matrix is constituted by a polyvinyl chloride film or by a film consisting of a copolymer comprising 80% and 90% low density polyethylene and 10% to 20% ethylene vinyl acetate.

8 - Photovoltaic module characterized in that it comprises at least one photovoltaic element associated with an optically active coating according to at least one of claims 1 to 7. 9 - Photovoltaic module according to the preceding claim characterized in that it further comprises components C0A- ^ _ti8tocke8 where the retransmission wavelength is between 550 and 800 nanometers is less than the wavelength of absorption is between 1000 and 1500 nanometers.

10 - Photovoltaic module according to claim 8 or 9 characterized in that it comprises a reflective rear face, the photovoltaic element being encapsulated in an optically doped matrix light cascade to form said coating.

11 - Photovoltaic module according to claim 8 or 10 characterized in that it comprises a plurality of photovoltaic elements forming a matrix with an expansion between 0.25 and 0.75, the areas between said photovoltaic elements being transparent.

12 - Photovoltaic module according to claim 8 or 11 characterized in that the matrix encapsulating the photovoltaic elements include remanent compounds for restoring light in the absence of insolation.

13 - Photovoltaic module according to claims 8 to 12 characterized in that binomial films and / or encapsulation plates is formed in the manner, on the front face, the light cascades with MOAs are arranged on the rear face, the CL mixed MOAs and COAs are arranged.

14 - Polymer granules for the manufacture of optically active coating according to claim 1 characterized in that they consist of a transparent matrix containing a plurality of optically active constituents absorbing the light energy in a first absorption wavelength _A1 and retranscribes the energy in a second lambda _R1 wavelength greater than lambda _M , said optically active constituents being chosen so that the retransmission wavelength lambdaR1 of at least one type of constituent corresponds to the lambda _A2 absorption wavelength of at least a second type of constituents, characterized in that the ratio C ₂ / C ₁ between the concentration C ₁ of the optically active constituents of a first type with respect to the concentration C ₂ of the optically active constituents of said second type is between 0.1 and 0.2 ; C _i designating the concentration in moles per liter of the component i relative to the doped matrix.

Polymer granules for the manufacture of optically active coating according to claim 1, characterized in that the optically active molecules are incorporated in a micronized PMMA matrix and / or pulverulent doped light cascade, and then mixed in the EVA granules.

16 - agricultural film is produced according to claim 1 characterized in that the films of different qualities and / or varied thicknesses are simultaneously co-extruded by the same machine.

17 - optically active coating for improving the photosolar efficiency according to any one of the preceding claims, characterized in that the concentration is a function of the thickness of the doped matrices by multiplying the thickness of a layer by the number of layers .

18 - optically active coating for improving the photosolar yield according to any one of the preceding claims, characterized in that the concentration is a function of the molecular weight of the MOAs, which is a function of the number of polycyclic nuclei.