WO2011091903A2

WO2011091903A2 - Luminescent solar concentrator module having renewable active layer

Info

Publication number: WO2011091903A2
Application number: PCT/EP2010/069573
Authority: WO
Inventors: Ingo Ramsteiner; Hendrik Boedeker
Original assignee: Robert Bosch Gmbh
Priority date: 2010-01-26
Filing date: 2010-12-14
Publication date: 2011-08-04
Also published as: EP2529414A2; DE102010001220A1; WO2011091903A3

Abstract

The invention relates to a luminescent solar concentrator module (1), at least comprising a plate-shaped substrate (2) of a transparent carrier material and an active layer (3), arranged on a top surface of the substrate (2) and containing at least one species (4) of a luminescent material, the active layer (3) being renewable. The invention further relates to a method for producing a luminescent solar concentrator module (1) according to the invention.

Description

description

title

The present invention relates to a luminescence concentrator module with a renewable active layer and a method for producing such a module.

State of the art

The reduction of the cost of the generated electrical energy is the main objective of the development of new photovoltaic (PV) concepts. The yield of a solar module depends essentially on the active area and the conversion efficiency of the cell. However, since the cost of a solar cell increases significantly with their area, a simple enlargement brings only low economic benefits. Attractively, therefore, is the use of concentrators in which the sunlight is focused with lenses or concave mirrors on small but highly efficient cells. However, these classic concentrator concepts require a mechanical tracking of the respective concentrator module to take into account the respective position of the sun.

In addition to these classic concentrators, so-called luminescence solar concentrators (LSCs') have been developed, which do not require tracking of the module to adapt to the respective position of the sun. The principle of action of luminescence solar concentrators was already in 1977 by Goetzberger and

Greuble in Appl. Phys. 14 (1977) 123-139, but the luminescent dyes available at that time were not yet powerful enough. Luminescent concentrators have, in a basic construction, as also described in High-Efficiency Organic Solar Concentrators for Photovoltaics, Michael J. Currie, et al., Science 321, 226 (2008), a transparent glass or glass

Plastic plate on that with a luminescent layer, for example a luminescent organic dye. This luminescent layer, also called a luminescent layer, absorbs a specific spectral range of the sunlight, for example blue, and emits light having a slightly larger wavelength, such as, for example, green. The generated light, in particular fluorescent light, couples into the system as in a light guide and is predominantly held by total reflection on the plate surfaces in the plate and is guided at one end face to a solar cell adapted for the corresponding wavelength. In the aforementioned publication by Currie et al., And in the patent DE 26 20 1 15 C2 is also described that to increase the efficiency of several such transparent plates with different luminescent layers in a multi-concentrator, a so-called tandem arrangement, are installed which can successively use all spectral ranges of sunlight.

The organic dyes previously used for the luminescent layer have only a limited shelf life. This is particularly true for the conditions to which a solar concentrator module is exposed, such as high temperatures and sunlight. The regular disposal and replacement of the solar concentrator modules not only reduces the economy and

Environmental compatibility of this technology, but is independent of all factual considerations also an image problem and has a negative impact on customer acceptance. To improve the durability of the luminescence concentrator modules is increasingly researched on new and more durable dyes and make them more durable (Craig Morris, photovoltaic 01/2009, p.56-57).

Disclosure of the invention

According to the invention, it is proposed to provide a luminescence concentrator module which comprises at least one plate-shaped substrate made of transparent carrier material and an active layer arranged on one surface side of the substrate and comprising at least one species of luminescent material, the active layer being renewable. In other words, according to the invention, the active layer with the luminescent species can be removed from the substrate, in particular without residue, and replaced by a new active layer. The renewal of the active layer may, according to its durability, for example, be carried out at periodic intervals or at irregular intervals.

The plate-shaped substrate of transparent support material may be, for example, a glass sheet or a sheet of plastic such as polycarbonate or polymethylmethacrylate. The glass panes or plates can, in particular plane-parallel, be formed with two surface areas which are opposite to one another and with relatively narrow end faces. It is essential for the substrate according to the invention that the transparent carrier material has a higher refractive index than the surrounding medium, wherein the surrounding medium may be in particular air.

The active layer is also referred to as luminescent layer according to the invention.

The substrate with the luminescent layer applied thereto is also referred to as a collector plate according to the invention. Preferably, the substrate and luminescent layer are chosen such that they have approximately the same refractive index, so that the active layer and the substrate form an optical unit. In other words, substrate and active layer are optically coupled together.

Advantageously, according to the invention, unlike the previously known concepts, the complete concentrator module no longer has to be replaced after expiration of the durability of the active layer, but only the luminescent layer is replaced. This results in ecological and cost savings also economic advantages over the disposable concentrator modules, which must be disposed of completely after their lifetime. In addition, it is also possible to replace the active layer by an identically composed and configured layer or by a different layer. For example, if desired, an active layer having an improved or more effective luminescent species be applied. Advantageously, previously known module structures can easily be adapted according to the invention with a renewable luminescent layer and thus have a significantly longer service life. In one embodiment of the invention, the species may be luminescent

Material in the active layer, a fluorescent dye, in particular a fluorescent organic dye. Examples of such organic dyes are rhodamine, fluorescein, xanthene, cyanine, oxazine, perylene, naphthylimide, naphthyldiimide, stilbene, pyrromethene and coumarin dyes. This list is not exhaustive and it is according to the invention also

Mixtures of a plurality of dyes, in particular the above-mentioned organic dyes, and / or other fluorescent species or more complex fluorescence systems can be used, as described, for example, in the work already cited by Currie et al. showed 4- (dicyano-methylene) -2-t-butyl-6- (1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran along with rubrene utilizing Förster energy transfer.

According to the invention, quantum dots can also be used as active species, which are understood to mean inorganic nanoparticles which have in particular fluorescence properties, are nanoscale and in particular consist of semiconducting materials. Preferably, as the quantum dots according to the present invention, semiconductive materials selected from the group consisting of InAs, InP, GaAs, GaP, GaN, InGaAs, GalnP / InP, CdO, CdSe, CdS _, CdTe, ZnO, ZnS, ZnSe, ZnTe, PbS, PbSe, PbTe, HgS, HgSe and HgTe. The quantum dots can according to the

Invention also be sheathed with an organic shell. For the hydrophobization of the quantum dots, these may preferably be surrounded by long-chain alkylamines, alkenylamines, aromatic amines, thiols, carboxylic acids, carboxylic esters, phosphoric esters, phosphonic esters, phosphenes and / or phosphane oxides. For hydrophilization, these may preferably be encased with mercaptocaboxylic acids, aminocarboxylic acids, thioalcohols, aminoalcohols, aminoalkylsiloxanes, thioalkylsiloxanes, hydroxycarboxylic acids and / or carboxylic acid esters. Quantum dots, as indicated above for the organic dyes, may also be used in admixture with other fluorescent species in the active layer. The active layer of the luminescence concentrator module can be designed according to an embodiment of the invention as a peelable paint and / or peelable film. In this case, the luminescent species can be introduced, for example, in a clearcoat and applied with this as a film-shaped coating, in particular polymer coating, to the substrate, this being according to the invention, if necessary, from the substrate again like a foil peelable. The luminescent species can be mixed in, for example, dispersed or dissolved in monomers or monomer solutions or dispersions of the coating system. The application of the paint to form the luminescent layer on the substrate can be carried out according to the invention by simple and known paint application methods. The application of the paint can be carried out for example by means of a spray gun, by roller, roller or brush application. Advantageously, therefore, the renewal of the active layer in the luminescence concentrator module according to the invention can also be carried out by a final user himself. Particularly suitable lacquers have a low optical absorption coefficient in solar spectral ranges and furthermore a refractive index which comes as close as possible to that of the substrate.

Lacquer systems which can form film-like coatings which can be pulled off in accordance with the invention are known. For example, DE 41 10 136 A1, DE 41 10 097 A1, DE 196 49 263 C1, DE 600 25 775 T2 and DE 43 25 566 A1 describe suitable coating systems as base systems for the luminescent active layer according to the invention. These paint systems are weather-resistant and also suitable for glass or plastic surfaces. Self-adhesive films can also be produced from the coating systems described in DE 41 10 136 A1, for example, which are subsequently applied to a substrate surface and can be completely removed from the substrate even after prolonged periods of, for example, one year. The film-like coatings can be removed by hand as a film.

Advantageous coating systems which can be used according to the invention as a base system for receiving the luminescent species and coated on substrates such as glass panes are, for example, water-based acrylate polymers which are resistant to UV light and weatherproof. The active species can, for example, such paints are easily applied by spraying by spray gun, but also with a roller or brush on a substrate according to the invention. Even after periods such paints can be removed without residue and very easily by hand again. Advantageously, the paint application requires no pretreatment such as a primer or sanding and is therefore easy and inexpensive. Removed, solid paint residues can be recycled to the recycling system for light packaging 'yellow sack'.

In another embodiment of the luminescence concentrator module according to the invention, the active layer can be designed as a washable and re-applicable paint. Here, in terms of weather resistance, a water-resistant, but advantageous with other solvents, such as alcohols, turpentine and / or soluble paint advantageous.

According to one development of the invention, the luminescence concentrator module can be coupled to at least one solar cell. This is also referred to as luminescent solar concentrator module or luminescent solar module according to the invention. The solar cells can be arranged in particular on the end faces of the collector plate. The solar cells can be fixed, for example, with an optically transparent adhesive. In this case, the solar cells can completely surround the collector plate as a frame or be attached only to selected end faces. The luminescent layer absorbs short-wave sunlight and emits light of a larger wavelength, which is largely coupled into the transparent substrate and directed in a light guide on the solar cells at the end face. The end faces thus each form a luminescent light exit surface. Thus, according to the invention, an efficient conversion of light energy into electrical energy can be achieved. If the end faces are not completely provided with solar cells, a part of the faces of the collector plate can be mirrored. In this way, radiation losses can be avoided and the efficiency can be increased, while at the same time the number of cost-intensive solar cells can be reduced. In a further preferred embodiment, the invention provides that the solar cell is tuned to a specific wavelength range of the light emitted by the species of luminescent material. Advantageously, as a result, the energy conversion can be optimized and the efficiency of the module according to the invention can be further increased.

In another embodiment of the luminescence concentrator module according to the invention, the latter can be provided with one or more further luminescence concentrator modules, comprising at least one plate-shaped substrate made of transparent carrier material and an active layer arranged on a surface side of the substrate containing at least one species of luminescent material, lying one above the other, optically separated from each other, wherein the luminescence concentrator modules each have a different active layer, the different spectral regions of the sunlight use.

In other words, a plurality of luminescence concentrator modules can be installed in a so-called tandem arrangement. The efficiency of such a tandem arrangement can be significantly increased compared to a single concentrator module. Conveniently, so the various

Wavelength shares of sunlight in the optically separated concentrator modules are collected and supplied to each adapted solar cells. Optically separated according to the invention means that the luminescence concentrator modules are separated by a medium having a lower refractive index. The various active layers of the concentrator

Modules can be selected so that the converted into luminescent light spectral regions of the light overlap.

In another embodiment of the luminescence concentrator module according to the invention, this can be a device for absorption and

Implementation of the by the luminescence or the concentrator modules still continuous radiation, such as thermal radiation include. According to the invention, conversion is understood to mean the conversion of the light radiation energy into electrical energy. Advantageously, it is possible according to the invention to use successively all spectral ranges of the light and thus to optimize the efficiency of the modules. It is also included according to the invention that the various embodiments of the above-described luminescence concentrator module can optionally be realized individually or in combination with one another

The invention further relates to a method for producing a luminescence concentrator module which comprises at least the following steps:

A) providing a plate-shaped substrate made of transparent carrier material,

B) applying an active layer containing at least one species of luminescent material, as a film-shaped coating on a surface side of the substrate, wherein

C) the active layer can be removed without residue if necessary and is renewable by applying a new active layer.

The active layer may be, for example, a clearcoat or a film containing one or more luminescent species. The luminescent material may be a fluorescent, especially organic, dye. Examples of suitable dyes according to the invention are rhodamine, fluorescein and coumarin dyes, this list is not meant to be exhaustive. In this case, reference is made explicitly to the executors for the luminescence concentrator module according to the invention.

If the active layer is no longer functional, for example as a result of aging or damage, this can be replaced in step C) according to the invention by a novel active layer according to the invention. This newly applied coating may conveniently also be renewable. Thus advantageously no longer, as usual, the entire module must be replaced. The service life of such a module can be significantly extended. Overall, the cost-effectiveness and customer acceptance of photovoltaic concepts in connection with luminescence concentrator modules according to the invention can be increased. Step C) of the process according to the invention can be repeated almost as often as desired. The service life of the module is limited only by mechanical damage to the substrate plate or solar cell. In particular, the active film-like coating can be designed as a peelable paint or as a peelable film. Alternatively, the luminescent layer can be realized as a water-resistant, but with solvents, such as alcohols, washable paint. Removing the active

Layer can therefore according to the invention in a simple manner, for example by removing the active layer by hand, take place.

Another advantage is that the active renewable layer newly applied in step C) may be the same or different than the original or previous active layer. Optionally, according to the invention, it is even possible to apply improved coatings containing, for example, a more durable or more effective fluorescent dye.

In one embodiment variant of the method, the application of the active layer in step B) and / or step C) can be effected by simple and known lacquer application processes, in particular by means of spraying, spraying, brushing or rolling. Advantageously, according to the invention, therefore, both the removal and the reapplication of the active layer may also be carried out by an end customer himself and does not require the involvement of specialist personnel or customer service, so that no additional costs for an end customer have to arise. With regard to further features and / or advantages of an inventive

Method is hereby explicitly referred to the explanations in connection with the embodiments of the luminescence concentrator module.

The invention will be explained below with reference to embodiments in conjunction with the figure, without being limited thereto.

Show it

1 is a schematic sectional view of a luminescence concentrator module according to the invention, Fig. 2 is a schematic oblique plan view of a double module according to the invention;

FIG. 1 shows a schematic sectional view of a luminescence concentrator module 1 according to the invention. This has a plate-shaped substrate

2 made of transparent carrier material. The substrate 2 may be, for example, a glass sheet or a sheet of plastic such as polycarbonate or polymethylmethacrylate. The glass sheet or plate made of transparent material as a substrate may be formed in particular plane-parallel with two opposite surface-extended surface sides and relatively narrow end faces. It is essential for the substrate 2 according to the invention that the transparent carrier material has a higher refractive index than the surrounding medium. The surrounding medium is usually air. On one surface side of the substrate 2, an active layer 3 is arranged, which comprises at least one species 4 of luminescent

Contains material, according to the invention, the active layer is renewable. Advantageously, according to the invention, the active layer 3, which is also called a luminescent layer with the contained luminescent species 4, can be removed from the substrate, in particular without residue, and replaced by a new active layer 3. For the sake of clarity only, a luminescent species 4 in the active layer 3 and an incident light beam A are shown. The substrate and the renewable luminescent layer are optically bonded together according to the invention. Preferably, both layers have the same as possible refractive index. As a result, advantageously, the reflection of rays at the

Contact area between the active layer 3 and the substrate 2 are minimized. The renewal of the active layer 3 may, according to its durability, for example, take place at periodic intervals or at irregular intervals. The luminescent species 4 may be, for example, a fluorescent dye, the short-wave

Solar radiation absorbed and less energetic radiation, also for the sake of clarity simplified with three beam paths B, emitted, which largely couples into the substrate 2 and is directed as in a light guide to the end faces. At one or more end faces, a solar cell 5 may be arranged, which optimally to the

Wavelength range of the emitted radiation is adjusted. In this way The conversion of light energy into electrical energy can be done more efficiently. In order to avoid radiation losses and, moreover, to be able to save expensive solar cells, reflectors, ie mirrors 6, can be arranged on further end faces of the substrate 2. According to the invention, the luminescent layer, for example, as a peelable paint or as a washable

Paint to be realized. Advantageously, by replacing the active layer, which is subject to aging, inter alia by the fact that the luminescent species 4 usually has only a limited durability, obtained by a new fresh active layer 3, the performance of the modules 1, or restored, become.

FIG. 2 shows a luminescence concentrator module 1 a according to the invention, the latter being arranged with another luminescent concentrator module 1 b optically, for example separated by an air gap 7, from one another to form a double module. The solar cell on the, facing the viewer, front was omitted for schematic and simplified representation of the beam paths in the figure. The luminescence concentrator 1 a, on which the radiation to be used first impinges, may expediently be designed so that the shorter-wavelength and higher-energy components of the sunlight, including the UV, in

Luminescent light, in particular fluorescent light, also short wavelengths are converted. The solar cell 5a can be adapted to this wavelength range, that is, consist of a semiconductor material with a relatively high band gap. The luminescent species 4a in the active layer 3a absorbs only in the region of short wavelengths, shown by the arrow A, and allows the light to pass unhindered in overlying wavelength ranges. This applies to the luminescence concentrator 1 b, which comprises a luminescent layer 3 b, which can convert a further wavelength range B and supplies the solar cell 5 b. The solar cell 5b may also be designed according to the emitted radiation of the luminescent species 4b and consist of a semiconductor material of smaller band gap than the solar cell 5a. According to the invention, it is possible to arrange more than two modules 1 a, 1 b together functionally with respect to a multiple concentrator module and thus successively use all wavelength ranges for generating electrical energy. One or all active layers 3a and 3b can be made renewable according to the invention. It is According to the invention, it is also possible to additionally combine a luminescence concentrator module 1a or a double or multiple luminescence concentrator module formed therewith with a device which absorbs the radiation which can not be converted by the solar cells, for example thermal radiation, and optionally for Generation of electrical energy can use. This can be, for example, an additional flat thin-film solar cell which can use transmitted light up to 1100 nm.

In summary, the invention provides a luminescence concentrator module with which the service life can be extended compared to previously known modules. The economy and environmental compatibility, especially in connection with the use as a luminescent solar concentrator module, can be significantly increased. Advantageously, previously known luminescence concentrator structures can be adapted and improved according to the invention in a simple manner by using a renewable active layer.

Claims

claims

1 . A luminescence concentrator module (1), comprising at least one plate-shaped substrate (2) made of transparent carrier material and an active layer (3) arranged on a surface side of the substrate (2), containing at least one species of luminescent material (4) in that the active layer (3) is renewable.

2. luminescence concentrator module (1) according to claim 1, characterized in that the species (4) of luminescent material is a fluorescent dye, in particular a fluorescent organic dye.

3. luminescence concentrator module (1) according to claim 1 or 2, characterized in that the active layer (3) is designed as a peelable paint and / or peelable film.

4. luminescence concentrator module (1) according to claim 1 or 2, characterized in that the active layer (3) is designed as a washable and re-applicable paint.

5. luminescence concentrator module (1) according to one of the preceding claims 1 to 4, characterized in that it is coupled to at least one solar cell (5).

6. luminescence concentrator module (1) according to claim 5, characterized in that the solar cell (5) is tuned to a certain wavelength range of the light emitted by the species (4) of luminescent material.

7. luminescence concentrator module (1) according to one of the preceding claims 1 to 6, characterized in that this with one or a plurality of further luminescence concentrator modules (1b) at least comprising a plate-shaped substrate (2b) made of transparent carrier material and an active layer (3b) arranged on a surface side of the substrate (2b) containing at least one species (4b) of luminescent material, one above the other lying, optically separated from each other, is arranged, wherein the luminescence concentrator modules (1 a, 1 b) each have a different active layer (3a, 3b), the different spectral regions of the light, in particular sunlight use.

Luminescence concentrator module (1) according to one of the preceding claims 1 to 7, characterized in that it comprises a device for absorption and conversion, the radiation passing through the or the luminescence concentrator modules radiation.

9. A method for producing a luminescence concentrator module (1) comprising at least the following steps

A) providing a plate-shaped substrate (2) made of transparent carrier material,

B) applying an active layer (3) containing at least one species (4) of luminescent material, as a film-shaped coating on a surface side of the substrate (2), wherein

C) the active layer (3) can be removed without residue if necessary and is renewable by applying a new active layer.

10. The method according to claim 9, characterized in that the application of the active layer (3) in step B) and / or step C) by Lackapplikationsprozesse, in particular by means of spraying, spraying, brushing or rolling, takes place.