GB2593857A - Photovoltaic Modules including solar cells and methods for manufacture - Google Patents

Abstract

A photovoltaic module 100 comprises a first substrate 110, a second substrate 150, a light-absorbing photovoltaic material arrangement 160 between the first and second substrates fabricated to provide one or more photovoltaic cells, and an electrode arrangement 200. The first and second substrates are directly mutually bonded to provide a hermetic seal 250 around the light-absorbing photovoltaic material arrangement. The hermetic seal may be provided by at least one of: thermally fusing the peripheral edges of the substrates together; and applying polymeric sealing material at the peripheral edges of the substrates to bond them together. The first and second substrates are at least partially transmissive for light of visible wavelengths. A part of the first substrate may be provided with, or composed of, at least one material 240 that reduces transmission through the first substrate of ultra-violet and/or infra-red radiation. The arrangement results in a prolonged operating lifetime by reducing degradation due to oxidation and moisture absorption.

Description

PHOTOVOLTAIC MODULES INCLUDING SOLAR CELLS AND METHODS FOR MANUFACTURE

TECHNICAL FIELD

The present disclosure relates to photovoltaic modules including photovoltaic (i.e. "solar") cells, for example photovoltaic modules that are susceptible to being incorporated into buildings and pre-fabricated building sections such as windows and building canopies. Moreover, the present disclosure relates to methods for (namely, methods of) manufacturing aforesaid photovoltaic modules. Furthermore, the present disclosure relates to methods for (namely, methods of) generating electrical power from aforesaid photovoltaic modules.

BACKGROUND

A photovoltaic cell, also known as a "solar cell", is a device which converts light energy received at the photovoltaic cell into electrical energy. The photovoltaic cell employs a photovoltaic effect, wherein photons present in the light energy received at the photovoltaic cell interact with electrons present in the photovoltaic cell to raise them to a higher energy state, in which the electrons are no longer tightly bound to atoms and thereby become free to move through a photovoltaic material employed to fabricate the photovoltaic cell; when such an electron becomes free to migrate, there is generated a corresponding positive charge, referred to as a "hole", that is able to migrate in an opposite direction to its corresponding electron in a presence of an electric field existing within the photovoltaic cell. Migration of the electrons and "holes" gives rise to an output current generated from the photovoltaic cell.

Conventional photovoltaic cells employ semiconductors, such as Silicon or 30 Gallium Arsenide, as a light-absorbing photovoltaic material. These semiconductors are relatively efficient at converting received light energy into electrical energy (for example, approaching 26% conversion -2 -efficiency), but are also very costly. Accordingly, recent attention has been focused on employing cheaper light-absorbing materials, which can be applied as a thin film onto planar substrates. These cheaper light-absorbing materials include dyes and nnetalorganic compounds such as: (i) copper phthalocyanine and ruthenium-centred compounds; and (ii) organic polymers, including poly(3-hexylthiophene) (P3HT), phenyl-C61-butyric acid methyl ester (PCBM) and poly[2-nnethoxy-5-3(3,7 -dimethyloctyloxy)-1-4-phenylene vinylene] (abbreviated as MDMO:PPV).

However, these cheaper light-absorbing materials are less efficient at converting received light-energy into electricity, in comparison to aforementioned Silicon and Gallium Arsenide materials. The cheaper light-absorbing materials allow for reel-to-reel, non-vacuum and solution processes to be used to deposit these materials, for example polymers, as active light-absorbing layers onto lightweight, low-cost and flexible substrates.

As aforementioned, contemporary organic photovoltaic materials exhibit a relatively low efficiency of conversion of received light-energy into corresponding electrical energy, for example much less than 10% efficiency of conversion; moreover, an operational lifetime of aforesaid polymer materials is relatively short, for example typically in a range of tens to a few thousands of hours, due to degradation arising on account of exposure. Such exposure arises on account of: (i) water moisture; (ii) oxygen and associated oxidative degradation; and (iii) ultra-violet (UV) light exposure, for example from UV present in incident sunlight.

The degradation arises on account of the polymers typically comprising conjugated systems of double bonds that function as effective charge transporters, wherein the conjugated systems of double bonds are -3 -susceptible to rupture when exposed to highly energetic photons (for example shorter radiation wavelengths present in light radiation such as ultraviolet radiation (UV)); moreover, the conjugated systems of double bonds, being unsaturated, are reactive with Oxygen and water vapour.

Furthermore, contemporary encapsulation methods that are compatible with low-cost, reel-to-reel flexible substrate processing and manufacture, do not provide sufficient protection from ingress of water moisture or Oxygen to enable lifetimes of such conjugated systems of double bonds to be sufficient for practical photovoltaic (PV) device applications.

Conventionally, an opaque and reflective back-layer is often provided to such a given photovoltaic cell employing organic photovoltaic materials, either as a part of a substrate of the given photovoltaic cell or as a separate external backing to the given photovoltaic cell when it is used; the purpose of this opaque and reflective back-layer is to reflect back into the photovoltaic cell that fraction of the light energy that has not been absorbed by the active light-absorbing layers in the photovoltaic cell on first pass. While such a second pass of the light energy through the photovoltaic cell is capable of increasing the efficiency of the photovoltaic cell, the efficiency increase is generally only very slight, because a proportion of useful frequencies of the reflected light has already been much reduced by its first pass through the photovoltaic cell.

Conventionally, for reasons of cost, convenience, electrical connectivity and mechanical strength, such photovoltaic cells are often composed of, and manufactured to have, layers that are contiguous and solid, including a substrate and encapsulating layers. Such a contiguous solid structure is capable of providing sufficient mechanical strength for such photovoltaic cells to be used as structural components, for example in building cladding; however, this solid structure also leads to the photovoltaic cells having a high thermal conductivity that makes the photovoltaic cells unsuitable on their own as thermally insulating structures. For example, if the -4 -photovoltaic cells are incorporated into building facades, such photovoltaic cells must usually be backed with additional layers of thermal insulation or insulating glass.

The present disclosure aims to mitigate or overcome these aforementioned problems.

It will be appreciated that transparent or translucent photovoltaic (PV) cells are desirable in practical applications such as building components; such building components including PV cells that provide, when in operation, both light transmission therethrough and electricity generation; such a dual functionality is important to end users. In such an example of a building component providing both light transmission and electricity generation, it is desirable that light is transmitted in a range 100/0 to 90% of a total visible wavelength spectrum, usually with some colour tinting being imparted through preferential absorption of specific visible light wavelengths. For several reasons, it is often desirable to block transmission of certain non-visible wavelengths into PV cells, particularly those non-visible wavelengths in the ultraviolet and infra-red regions of the wavelength spectrum. The dual functionality of visible light transmission and electricity generation is conventionally achieved by using a partially absorbing active thin-film PV layer coupled with thin layers of a transparent conductive oxide (TCO) layer placed or coated on each side of the partially absorbing active thin-film PV layer, to pick up (i.e. collect) current from the PV cell while still enabling light to be transmitted through a structure of the PV cell. A planar glass sheet is typically used as a substrate to support the layers, to protect the active PV cells, and to allow light transmission through the active PV cells.

For applications where transparency or translucency of the PV cells is not a requirement, a TCO layer, if used at all, is generally used only on an outer side of the PV cells, through which incident light is received by the PV cells and the other TCO layer is typically replaced with a cheaper and more -5 -conductive metallic contact. Where a TCO layer is not used at all, then typically the outer side of the PV cells will incorporate a network of metallic conductive tracks to collect current generated by photovoltaic effect.

In some PV cells, the TCO layer employed, and any associated glass substrate employed, beneficially provides a vital role in absorbing or reflecting specific wavelengths that potentially damage or reduce an efficiency an active photon absorbing layer employed in the PV cells, or that are otherwise undesirable. An example, Indium-Tin Oxide layers are used as a selective barrier to short wavelength infra-red radiation (for example, infra-red radiation having a wavelength in a range of 1.4 Rm to 3 Rm) in solar-control glass.

In some types of PV cells based on types of intermixed phases of exitonic materials, such as dye-sensitised and organic polymer PV cells, a coating or interlayer is beneficially used between one or more photon absorbing layers and one or both of conductive current-collecting layers present. This coating or interlayer is susceptible to reduce loss mechanisms and to enhance a transfer of current to current collectors that are utilized.

Moreover, in some PV cell assemblies, to enhance overall efficiency of conversion of received light radiation to corresponding generated electricity, multiple cells and different types of cells are structured sequentially one on top of another in a stacked manner, so that light not absorbed by one PV cell in the sequence is absorbed by a next PV cell in the sequence. Such a type of structure is susceptible to being used in both translucent and in non-translucent PV cell assemblies.

For all types of PV cells, and also photovoltaic modules including such PV 30 cells, it is generally important to try to maximise an efficiency of conversion by allowing as much as possible of incident light received at the PV cells to reach active photon absorbing layers of the PV cells. One problem with TCO -6 -layers or other upper-side electrical contacts is that they can absorb or reflect some proportion of the received incident light, and thereby preventing it from reaching the active layers where a portion of that light would otherwise be converted to useful electrical energy.

A second problem for commercial applications of PV cells, and in particular transparent or translucent PV cells, is that TCO layers employed in the PV cells are an expensive part of overall cost of manufacturing the PV cells. Highest performance TCO materials usually include Indium, a scarce and increasingly expensive metallic element. Moreover, whatever type of TCO composition is employed in the PV cells, multiple deposition processes are required to lay down coherent, transparent and highly conductive oxide layers and these processes are generally complex, expensive and slow.

In operation, when exposed to received light radiation, individual PV cells generally generate output electrical voltages of less than one volt (although some PV materials can enable slightly higher voltages to be generated), with PV cell currents generated being dependent upon areas of the PV cells. Collecting electrical power over a large area of PV cells involves very significant resistive losses, when such collecting of electrical power is implemented at low voltages and at high currents; moreover, significant losses can occur where the voltage and current output of PV cells need to be matched to usage requirements by subsequent power conditioning electronics (particularly if low voltages have to be stepped up to much higher voltages via use of solid-state inverters). For these reasons, small-area individual PV cells are generally interconnected in electrical series within a photovoltaic module or assembly of PV cells to create a higher output voltage before any power conditioning is applied to increase the output voltage to yet higher voltages for consumption. -7 -

A third problem is that, from an aesthetic perspective, arrays of separated PV cells are generally perceived as less visually attractive in comparison to a uniform large area single cell.

A fourth problem is that the requirement for such PV cell interconnection introduces manufacturing complexity which contributes to cost of manufacturing photovoltaic modules including the PV cells. High tolerances required to achieve interconnection with minimum cell separation distances potentially lead to low production yields and premature in-service failures of modules including arrays of PV cells.

SUMMARY

The present disclosure seeks to provide an improved photovoltaic module that is more durable and provides a longer operating lifetime in comparison to known types of photovoltaic modules, for example based on the use of organ polymers as active photovoltaic materials therein.

The present disclosure seeks to provide an improved method for (namely, method of) manufacturing a photovoltaic module that is more durable and provides a longer operating lifetime in comparison to known types of photovoltaic modules, for example based on the use of organ polymers as active photovoltaic materials therein.

According to a first aspect, there is provided a photovoltaic module comprising: a first substrate that, when in operation, receives input light radiation, wherein the first substrate is at least partially transmissive for light of 30 visible wavelengths; -8 -a second substrate substrate, wherein the second substrate is at least partially transmissive for light of visible wavelengths; a light-absorbing photovoltaic material arrangement included between the first substrate and the second substrate, wherein the light-absorbing photovoltaic material arrangement is fabricated to provide one or more photovoltaic cells; and an electrode arrangement in contact with the light-absorbing photovoltaic 10 material arrangement that provides collection of an electrical output from the one or more photovoltaic cells; wherein the first substrate and the second substrate are directly mutually bonded to provide a hermetic seal around the light-absorbing photovoltaic 15 material arrangement.

The invention is of advantage in that directly mutually bonding to provide the hermetic seal around the light-absorbing photovoltaic material arrangement provides the arrangement with a prolonged operating lifetime by reducing its degradation due to oxidation and moisture absorption therein.

Optionally, in the photovoltaic module, the hermetic seal is provided by at least one of: (i) thermally fusing peripheral edges of the first and second substrates together; and (ii) by applying polymeric sealing material at the peripheral edges of the first and second substrates to bond them together.

Optionally, in the photovoltaic module, at least a part of the first substrate is provided with, or composed of, at least one material that reduces -9 -transmission of the input light radiation through the first substrate of at least one of: ultra-violet radiation, infra-red radiation.

Optionally, in the photovoltaic module, the at least one of the one or more photovoltaic cells includes at least one photon absorber layer and at least two conductive electrical current pick-up electrodes, wherein: (i) one of the electrical current pick-up electrodes functions, when in operation, as an anode; and (ii) the other of the electrical current pick-up electrode functions as a cathode, wherein a first side of the at least one of the one or more photovoltaic cells receives, when in operation, incident light and a second side of the at least one of the one or more photovoltaic cells, in which the conductive electrical pick-up electrodes are positioned on one side only of the at least one of the one or more photovoltaic cells.

More optionally, in the photovoltaic module, the at least one photon absorber layer transmits, when in operation, in a range of 10°/0 to 95% of the visible light incident on the at least one of the one or more photovoltaic 20 cells.

More optionally, in the photovoltaic module, the conductive electrical pickup electrodes are used to interconnect individual photovoltaic cells together in series with sequentially alternating anodes and cathodes.

More optionally, in the photovoltaic module, the one or more photovoltaic cells have their anodes and cathodes connected, wherein a given anode is in direct contact with only one cathode in series.

More optionally, in the photovoltaic module, an electron-blocking or hole-blocking interlayer is inserted between at least one photon absorber layer and one or both of the electrical current pick-up electrodes.

-10 -More optionally, in the photovoltaic module, the electrical current pick-up electrodes are selectively coated or doped to induce or inhibit electron or hole conducting characteristics.

More optionally, in the photovoltaic module, the anodes are in electrical contact with one of the phases in the at least one photon absorber layer, and cathodes are in electrical contact with another of the phases in the at least one photon absorber layer.

More optionally, in the photovoltaic module, the electrical current pick-up electrodes incorporate a continuous layer of a transparent conductive oxide.

More optionally, in the photovoltaic module, the electrical current pick-up electrodes incorporate a non-continuous layer (such as strips, separated by narrow gaps) of one or more transparent conductive oxides.

More optionally, in the photovoltaic module, the electrical current pick-up 20 electrodes incorporate a non-continuous layer of a metal or a metallic alloy.

More optionally, in the photovoltaic module, a first photovoltaic cell of the one or more photovoltaic cells is coupled to a second photovoltaic cell of the one or more photovoltaic cells, and wherein the second photovoltaic cell absorbs a portion of light that is transmitted through the first photovoltaic cell.

Optionally, in the photovoltaic module, the first and second substrates are made from a transparent or translucent glass.

Optionally, in the photovoltaic module, the light-absorbing photovoltaic material arrangement employs (namely includes) an organic polymer in its at least one photon absorber layer.

More optionally, in the photovoltaic module, the least one photon absorber layer includes a non-homogenous blend of electron donor, electron acceptor, hole-conducting and/or semiconductor phases, including materials such as organic polymers, oxides, carbon, electrolytes and catalysts.

Optionally, in the photovoltaic module, the at least one of the one or more photovoltaic cells includes at least one photon absorber layer and at least two conductive electrical current pick-up electrodes, wherein: (0 one of the electrical current pick-up electrodes functions, when in operation, as an anode; and (ii) the other of the electrical current pick-up electrode functions as a cathode, wherein a first side of the at least one of the one or more photovoltaic cells receives, when in operation, incident light and a second side of the at least one of the one or more photovoltaic cells, in which the conductive electrical pick-up electrodes are positioned on both sides of the at least one of the one or more photovoltaic cells.

According to a second aspect, there is provided a method for (namely, a 25 method of) manufacturing a photovoltaic module, wherein the method comprises: (i) providing a first substrate that, when in operation, receives input light radiation, wherein the first substrate is at least partially transmissive for light of visible wavelengths; -12 - (ii) providing a second substrate substrate, wherein the second substrate is at least partially transmissive for light of visible wavelengths; (iii) applying a light-absorbing photovoltaic material arrangement onto a least one of the first substrate and the second substrate, wherein the light-absorbing photovoltaic material arrangement is fabricated to provide one or more photovoltaic cells; (iv) applying an electrode arrangement in contact with the light-absorbing photovoltaic material arrangement that provides collection of an electrical output from the one or more photovoltaic cells; and (v) directly mutually bonding together the first substrate and the second substrate to provide a hermetic seal around the light-absorbing photovoltaic material arrangement.

Optionally, the method includes providing the hermetic seal by at least one of: (i) thermally fusing peripheral edges of the first and second substrates together; and (ii) by applying polymeric sealing material at the peripheral edges of the first and second substrates to bond them together.

Optionally, the method further includes manufacturing the light-absorbing photovoltaic material arrangement using deposition from a liquid solution or a liquid suspension.

More optionally, the method further includes using deposition techniques including at least one of: powder spraying, liquid spraying, dip-coating, spin-coating, curtain coating, casting, or printing.

-13 -Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

BRIEF DESCRIPTION OF THE DIAGRAMS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of 20 example only, with reference to the following diagrams wherein: FIG. 1 is a schematic illustration of a photovoltaic module according to

the present disclosure;

FIG. 2 is a schematic illustration of a structure of photovoltaic cells employed in the photovoltaic module of FIG. 1, wherein the photovoltaic cells are formed on one of two substrates employed to provide the photovoltaic module; FIG. 3 is a schematic illustration of an alternative structure of photovoltaic cells employed in the photovoltaic module of FIG. 1, wherein the photovoltaic cells are formed on two substrates employed to provide the photovoltaic module; and -14 -FIG. 4 is a flow diagram including steps of manufacturing the photovoltaic module of FIG. 1.

In the accompanying drawings, a non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DETAILED DESCRIPTION OF EMBODIMENTS

In overview, referring to FIG. 1, the present disclosure provides a photovoltaic module 100 comprising: (i) a first substrate 110, which is at least partially transmissive for light of visible wavelengths ("visible" referring to sensing characteristics of the human eye); (ii) a second substrate 150, which is at least partially transmissive for light of visible wavelengths; and (iii) a light-absorbing photovoltaic material arrangement 160 disposed between the first and second substrates 110, 150; wherein the first and second substrates 110, 150 are directly mutually bonded to each other, for example around their periphery, to form a hermetic seal 250 around the light-absorbing photovoltaic material arrangement 160.

The terms "first" and "second" are intended to indicate that, in use, light used to produce electricity will generally pass through the first substrate 110 before encountering the photovoltaic material arrangement 160, and unabsorbed light will generally exit the module through the second substrate 150. The photovoltaic module 100 is susceptible to be used, when in operation, in any orientation.

-15 -Beneficially, the photovoltaic module 100 of the present disclosure is manufactured to be a structural module, namely a structural module which is used to form part of the structure of a building (e.g. wall, window, roof, door and so forth). Beneficially, therefore, the photovoltaic module 100 as a whole is at least partially transmissive to light of visible wavelengths, such that to a human observer inside a building comprising such photovoltaic modules; the photovoltaic module 100 appears substantially transparent or translucent.

Optionally, the photovoltaic module 100 absorbs visible light of certain restricted radiation wavelengths, but in general it is desirable that at least 70% of light of visible wavelengths (for example, in a wavelength range of about 390nm to 780nm) are transmissible through the photovoltaic module 100, more optionally at least 75%, most optionally 80% or up to 85% or even 90% or 95%.

It is envisaged that the photovoltaic module 100 of the present disclosure can be used to create large area panels, comprised largely of glass, with an area up to about 6 square metres (per planar side), and which can be used in substitution for conventional glass windows and/or exterior glass cladding panels, for example, in the constructions of buildings such as houses, offices, shopping malls and smaller retail units, or public buildings such as libraries, museums, walls, auditoria and the like. The light-absorbing photovoltaic material arrangement 160 beneficially comprises a thin layer of material; beneficially, the thin layer of material is continuous, but, alternatively, can be implemented as a discontinuous layer. Optionally, the photovoltaic material arrangement 160 comprises an organic polymer such as polythiophenes or fullerenes, for example poly(3-hexylthiophene), as an active photovoltaic material. Beneficially, the photovoltaic material has a thickness of less than 10 microns (um), desirably less than 5 microns (um), more optionally less than 2 microns (um), and most optionally less than 0.51 micron (um).

-16 -The photovoltaic module 100 of the present disclosure typically utilises a photovoltaic material with a relatively low light-absorbing power conversion efficiency (compared to crystalline silicon solar cells, for example).

However, in the context of a structural module, intended to be substantially transparent or translucent, this relatively low light absorption power conversion efficiency becomes at least partially advantageous. Such a low electrical power generating capacity of such a photovoltaic module 100 can be offset by its use over large areas of a building, such that useful amounts of power can be generated.

Beneficially, the photovoltaic module 100, using transparent electrodes 200 for collecting generated current, is arranged so that it can receive light from both of its major planar surfaces. For example, such a photovoltaic module 100 can be advantageously mounted vertically with a major plane of the photovoltaic module 100 being oriented North-South, so that the two light receiving surfaces are facing East and West. In this orientation, such a photovoltaic module 100 will be active to sunlight received from an Eastern direction during mornings and from a western direction during afternoons, and can generate up to twice as much electrical power than an equivalent, conventional non-transparent photovoltaic module.

A single type of organic polymer will tend to absorb light with only a limited range of wavelengths. Optionally, it is desirable that the photovoltaic material comprises a plurality of different light absorbing molecules, wherein each of the light absorbing molecules has mutually differing light-absorbing characteristics. Such mutually different light-absorbing molecules are optionally provided in respective discrete locations of the photovoltaic module or, more optionally, are provided intimately mixed or as interdigitating layers.

-17 -The photovoltaic material arrangement 160 is conveniently deposited as a thin coating on a major surface of the first substrate 110 and/or the second substrate 150. For example, the photovoltaic material arrangement 160 is formed as a coating on an internally-facing major surface of the first substrate 110, or is formed as a coating on an internally-facing major surface of the second substrate 150.

Beneficially, the photovoltaic material arrangement 160 is deposited (ideally, without requiring a need to employ vacuum deposition conditions) from a solution or suspension of the active materials from a liquid. Suitable deposition techniques optionally include at least one of: powder spraying, liquid spraying, dip-coating, spin-coating, curtain coating, casting, and printing. Generally, beneficially, a deposition step is performed using a protective blanket of inert gas (such as Nitrogen, or a noble gas) to exclude Oxygen and/or water.

As aforementioned, the photovoltaic module 100 is formed, at least in part, by creating a hermetic seal 250 around the photovoltaic material arrangement 160, by directly mutually bonding the first and second substrates 110, 150 together, namely without a need to employ any intervening sealing arrangements, such as a gasket or the like. The first and second substrates 110, 150 optionally comprise a synthetic plastics material, for example transparent polycarbonate plastics material or transparent acrylic plastics material; more optionally, the first and second substrates 110, 150 comprise glass. Each of the first and second substrates 110, 150 optionally have a thickness in a range of 2 mm to 20 mm, more optionally a thickness in a range of 2 mm to 15 mm, and yet more optionally a thickness in the range of 2 mm to 10 mm.

Beneficially, the first and second substrates 110, 150 are manufactured from glass, wherein their associated photovoltaic material arrangement 160 is sealed by mutually bonding the first and second substrates 110, -18 -together, for example by using laser bonding along an outer periphery of the first and second substrates 110, 150, to create a high temperature melting of the substrates 110, 150 in a localised manner, under precise control; for example, an infra-red camera is used to monitor a region where mutual laser welding of the first and second substrates 110, 150 is occurring, wherein and laser beam power or a rate of moving of a laser beam (or both) is controlled via a feedback loop to ensure that reliable welding is achieved and that the substrates 110, 150 are not thermally stressed so that they crack. The resulting bond forms a hermetic seal 250 for the photovoltaic module 100, wherein the hermetic seal 250 is effective to exclude Oxygen and water which could potentially otherwise degrade the photovoltaic material arrangement 160.

Those skilled in the art will appreciate that the photovoltaic module 100 further requires electrodes 200 to conduct free electrons generated by the photovoltaic material arrangement 160. Conveniently, thin electrical conductors, namely electrodes 200, are embedded within the photovoltaic module 100. These electrodes 200 optionally comprise transparent conductive oxides ("TCO"), such as doped Tin Oxides, doped Zinc Oxides, Cadmium Telluride or similar. Example substances to use to manufacture the electrodes 200 include Indium-doped Tin Oxide (ITO) and Fluorine-doped Tin oxide (FTO).

Desirably, the photovoltaic module 100 will additionally comprise one or more substances 110, 150 which have the effect of altering one or more of a magnitude, an intensity, a frequency spectrum and a scattering direction of visible light transmission through the photovoltaic module 100. Alternatively, or additionally, such materials are optionally provided in separate layers 240, either independently or deposited on the first and/or second substrates 110, 150. Examples of such substances include filters to remove colour given to the transmitted light via an absorption spectrum -19 -of the active photovoltaic layer of the photovoltaic material arrangement 160.

Conveniently, the photovoltaic module 100 comprises an intermediate 5 layer 310, provided between the photovoltaic material arrangement 160 and the electrical conductors 200, namely electrodes. The intermediate layer 310 is optionally continuous; alternatively, the intermediate layer 310 is discontinuous; moreover, the intermediate layer 310 advantageously comprises a conducting material which inhibits the conduction or migration of electrons and/or holes and advantageously aids the transport of electrons/or holes by having a work function that forms an intermediate step between the two semiconducting layers and the electrode 200. An example of such a conducting material includes a substance comprising poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (abbreviated as "PEDOT:PSS"). The intermediate layer 310 conveniently has a thickness in a range of 2 nnn to 1000 nm.

Advantageously, optionally, the photovoltaic module 100 further comprises one or more materials, in gaseous communication with the hermetically sealed interior of the photovoltaic module 100 in which the photovoltaic material arrangement 160 is accommodated, to adsorb or react with residual Oxygen and/or water molecules therein. Examples of the one or more material include desiccants, such as silica gel and the like. Advantageously, the hermetically sealed interior of the photovoltaic module 100 incorporates a vacuum to provide a thermal barrier to conduction and convection between the first and second substrates 110, 150 Or encapsulating layers that bound the photovoltaic module 100.

Optionally, at least a part of the first substrate 110 is provided with, or 30 composed of, one or more materials which reduce the transmission through the first substrate of ultra-violet and/or infra-red radiation. The one or more materials (for example, a plurality of materials) reduce the -20 -transmission of ultra-violet or infra-red radiation by reflecting and/or absorbing radiation of these wavelengths. For purposes of the present disclosure, ultra-violet radiation means electromagnetic radiation with a wavelength in a range of 10 nm to 250 nm; moreover, infra-red radiation 5 means electromagnetic radiation with wavelengths greater than 900 nm, for example in a range of 900 nm to 5000 nm. The reduction in transmission of these ultra-violet and/or infra-red wavelengths is at least 10%, optionally at least 20%, more optionally at least 30%, and most optionally at least 40% (the comparison being between a substrate e.g. of 10 conventional glass, and a substrate additionally treated or formed with UV or IR-reducing materials).

Typically, different materials will be suitable for reducing the transmission of UV than will be suitable for reducing the transmission of IR.

Conveniently, therefore the first substrate 110 is provided with, or composed of, at least two different materials: one for reflecting or adsorbing UV, and one for reflecting or adsorbing IR. If desired, two or more different materials are used in combination for reducing the transmission of UV and/or two or more different materials are used for reducing the transmission of lit. These materials are susceptible to being used in any desired amount or ratio. Suitable materials for reducing the transmission of UV include oxides of metals such as Cerium, Bismuth, Tin, Antimony, Titanium and Zinc.

One or more suitable materials for reducing the transmission of IR through the photovoltaic module include oxides of metals such as Tin, Zinc, Antimony and Indium. Advantageously, the one or more materials are applied as a thin layer 240 or coating to the exterior and/or interior major surfaces of the first substrate 110. Each layer 240 or coating typically, for example, has a thickness in a range of 0.1 microns (mm) to 10 microns (1m).

-21 -The first and/or second substrates 110, 150 optionally are coated, or otherwise provided, with materials or substances used to impart desirable characteristics in conventional windows or exterior glass cladding panels. These include decorative and solar control films are manufactured by companies such as 3M® and Baekaert®.

Optionally, the photovoltaic module 100 is made reversible in its manner of operation, such that when not generating electricity by absorbing sunlight (e.g. at night-time, or when sunlight is obscured by cloud, fog or the like), the application of an external electrical charge to the photovoltaic module 100 can be used to produce illumination. Thus, by selecting particular modules in a substantially planar array (such as on the face of a large building), there can be provided illuminated patterns or recognisable images (such as letters, logos or the like) on the planar array; such recognisable images can be used, for example, for promotional and/or informational purposes.

Optionally, the photovoltaic module 100 is equipped a sensor (not shown) to detect any occurrence of damage and/or inactivity in relation to the photovoltaic module 100, for maintenance and/or security purposes, such that damaged and/or inactive photovoltaic modules 100 are replaced. Such a sensor is susceptible to being implemented from an inverter that provides information indicative of much output a given photovoltaic module 100 outputs for a corresponding given amount of received sunlight.

The aforesaid photovoltaic module 100 is susceptible to being manufactured using a variety of mutually different methods. In an example, there is provided a method for (namely, a method of) manufacturing a photovoltaic module 100, wherein the method comprises steps of: -22 - (a) assembling a first substrate 110, a second substrate 150, and a photovoltaic material arrangement 160 disposed therebetween; and (b) forming a hermetic seal 250 around the photovoltaic material arrangement 160 by bonding the first and second substrates 110, together, for example by directly bonding the first and second substrates 110, 150 together at peripheral edges thereof.

In this context, "direct bonding" means that the first and second substrates 110, 150 are mutually joined together to form a seal without any intervening sealing means, such as a gasket or adhesive. Preferably the first and second substrates 110, 150 are essentially formed of glass, and are heated (for example using a focused laser beam, for example using a CO2 laser beam) to cause localised melting and mutual fusion of the substrates 110, 150. Conveniently, the localised melting is affected by laser bonding as aforementioned. Optionally, a glass frit is added where the first and second substrates 110, 150 are to be fused together, whereon the glass frit has a lower melting temperature than glass of the first and second substrates 110, 150.

A glass frit is a paste including glass powder, organic binder, inorganic fillers and solvents. Such a low melting glass paste is milled into powder (grain size < 15 pm) and mixed with organic binder to form a printable viscous paste. Inorganic fillers, namely cordierite particles (for example, Mg2A13 [AlSi5018]) or Barium Silicate, are added to the glass paste to influence its properties, namely to lower a mismatch of thermal expansion coefficients between Silicon and glass frit. The solvents are used to adjust the viscosity of the organic binder. Several glass frit pastes are commercially available, for example FERRO FX-11-0366.

-23 -Advantageously, the photovoltaic material arrangement 160 is formed as a coating or layer upon internally-facing surfaces of at least one of the first and second substrates 110,150, as will next be described in greater detail.

Next, the one or more photovoltaic cells 230 of the aforementioned photovoltaic module 100 will be described in greater detail. The one or more photovoltaic cells 230 utilise an inter-penetrating blend of electron donor, electron acceptor, hole conducting or ion conducting materials as an active photon absorbing layer, such employed in dye-sensitised and organic polymer PV cells. Referring to FIG. 2, there is shown a photovoltaic module 100, including a plurality of individual photovoltaic cells 230. There is used a conductive current collector 200 placed on one side only of an active photon absorbing layer. Preferentially, the conductive current collector 200 comprises a sequential array of anodes (A) and cathodes (C) contacting one side of the active photon absorbing layer to create a plurlity of interconnected individual photovoltaic cells 230, wherein the anode (A) and the cathode (C) of each photovoltaic cell 230 are physically separated from each other by, for example, a gap in the electrode layer 200 and by the photon absorbing layer, while the anode (A) and cathode (C) of immediately adjacent photovoltaic cells are in direct electrical contact.

Different materials are susceptible to being used for each of the anodes (A) and cathodes (C); alternatively, advantageously, there is used a single electrode layer material in combination with a dopant or surface coating to modify selectively and define the alternating anodic and cathodic regions of each electrode layer 200.

Optionally, advantageously (for simplicity of manufacture and/or visual aesthetics of the cell array), there is utilised a continuous, unbroken, photon absorbing layer 160 between the first substrate 110 and second substrate 150 (which optionally typically comprise glass as aforementioned). Alternatively, for efficiency considerations, there is employed a physical isolation between the absorber layers between each -24 -photovoltaic cell 230, for example by laser scribing an array of photovoltaic cells 230 during manufacture, or by appropriate printing or masking techniques to create a gap.

Optionally, it is advantageous to minimise a distance that individual electrons, holes or ions have to travel to reach respective electrodes by utilising textured, or other high surface area electrodes, and/or to utilise an interpenetrating electrode network. An example of the latter case, a single anode and a single cathode of a given single photovoltaic cell (in an electrically interconnected array of such photovoltaic cells) comprise a very closely spaced and high surface area interdigitated pattern sharing a same 3-D volume or 2-D area, but are nevertheless not in direct physical contact.

Optionally, for simplicity of manufacture and/or visual aesthetics of the photovoltaic cell array, it is advantageous to utilise a continuous, unbroken photon absorbing layer. Alternatively, it is advantageous from efficiency considerations, to physically isolate the absorber layers between each photovoltaic cell 230, for example by laser scribing the photovoltaic cell array during manufacture, or by using appropriate printing or masking techniques.

When the photovoltaic module 100 utilizes a transparent or translucent type of photovoltaic cell 230, a single sided current collector will allow one of the TCO layers to be eliminated (namely a TCO layer either the first substrate 100 or the second substrate 150, depending upon any preferred absorption characteristics of the TCO or associated glass substrate). By such an approach, instead of using two expensive, high-specification glass substrates incorporating TCO coatings, only a single such substrate incorporating TCO is required with the other being replaced, for example, with a low-cost, lower-specification transparent substrate. Moreover, by such an approach, any requirement to align mutually the first and second substrates 100, 150 highly accurately during manufacture is avoided.

-25 -In a photovoltaic module 100 employing a non-translucent type of photovoltaic cell 230, such an approach of employing a TCO layer on only one of the first and second substrates 110, 150 eliminates a need for a current collector or a network of metallic conductive tracks on the first substrate 110. In an example implementation, current generated by the one or more photovoltaic cells 230 is drawn from the inside-facing surface of the second substrate 150, and incident radiation transmitted through the first substrate 110 passes unimpeded, unless filtered by a UV and/or infra-red filter layer 240, to the one or more photovoltaic cells 230.

EXAMPE 1: Referring to FIG. 1, a photovoltaic module in accordance with the present 15 invention is indicated generally by reference numeral 100. The photovoltaic module 100 is about 6 square metres (6 m2) in area, and has a total thickness in a range of 8 mm to 25 mm.

The photovoltaic module 100 comprises a first substrate 100 and a second substrate 150, both essentially formed of planar panes of glass. At least one of the first surface of the second substrate 150 and the inside-facing surface of the first substrate 110 is coated or embedded with a thin (namely, in a range of 0.055 pm to 10.5 iim, micron) layer of a transparent conductive material forming a network of transparent electrodes 200. In FIG. 1, there are optionally included electrodes 200 at both first and second substrates 110, 150, though optionally only one substrate incorporates such electrodes 200 to make manufacturing easier (to avoid a need to align the first substrate 110 to the second substrate 150 to a high accuracy during manufacture). Between the first and second substrates 110, 150, there is included a thin (less than 1 [im, micron) coating of a photovoltaic material 160, wherein the photovoltaic material 160 comprises a substantially homogeneous heterogenous blend of at least two semi- -26 - conducting materials, at least one of which is a plurality of light-absorbing organic polymer molecules, each molecule having differing light-absorbing properties. Suitable organic polymers include poly(3-hexylthiophene) (P3HT), phenyl-C61-butyric acid methyl ester (PCBM) and poly[2-methoxy- 5-3(3,7-dinnethyloctyloxy)-1-4-phenylene vinylene] (MDMO: PPV).

The photovoltaic semiconducting layer 160 optionally incorporates additional layers (not shown) as is common in the art of organic photovoltaic cells to modify a work function of the electrodes and/or control hole or electron injection.

An outwardly-facing surface of the first substrate 110 is coated with a thin layer 240 of a UV-reflective and infra-red absorbing/reflective material to prevent damage to the photovoltaic semiconducting layer 160 from ultraviolet radiation and from heat. Suitable UV/IR absorbing/reflective materials include oxides of metals such as Cerium, Bismuth, Tin, Antimony, Titanium, Indium and Zinc.

Beneficially, the first and second substrates 110, 150 are substantially transparent, transmitting, for example, up to 90% of light in the visible part of the spectrum. The photovoltaic module 100 is suitable for, and intended for, use as a structural module in buildings, for incorporation in, for example, walls, roofs, doors and windows, in place of conventional glass panels or other cladding materials. The photovoltaic module 100 is provided with electrical contacts (not shown) to conduct electricity from the photovoltaic module 100 to a load (e.g. an inverter); beneficially, copper or silver foil strips are employed to make contact to electrodes 200 on the inside-facing surface of the second substrate 150, wherein the foil strips are designed to survive laser welding of the first and second substrates 110, 150 together; alternatively, the electrodes 200 of the second substrate 150 are extended beyond a peripheral boarder whereat laser welding of the first and second substrates 110, 150 occurs, to allow -27 -contact to be made to the photovoltaic material arrangement 160 that is hermetically sealed between the first and second substrates 110, 150.

EXAMPLE 2:

There will next be described a method for (namely, a method of) manufacturing a transparent photovoltaic module 100 according to the present disclosure, with reference to FIG. 4.

Step 1. A glass planar substrate 150 is coated in a layer of transparent conductive oxide (having a thickness in a range of 50 nm to 1000 nm); conveniently, the coated glass planar substrate is sourced from an independent commercial supplier. The glass planar substrate 150 has its layer of transparent conductive oxide pre-patterned into strips of dimensions desired for individual photovoltaic cells 230 in the photovoltaic module 100. The glass planar substrate 150 with its layer of transparent conductive oxide is cleaned using solvents, (for example, isopropanol, acetone). The Step 1 is denoted by 500 in FIG. 4.

Step 7* A soluble transparent conductive layer is deposited via a printing technique, such as spray coating, as an even layer on the glass-ITO substrate 150 from the Step 1. This soluble transparent conductive layer comprises a material that is used as a hole-injecting layer. The Step 2 is denoted by 510 in FIG. 4. ;Step 3. Electron donating and accepting organic semiconductor materials are dissolved in a blend solution using a range of solvents such as chlorobenzene. The Step 3 is denoted by 520 in FIG. 4. ;Step 4. This solution from the Step 3 is then deposited as an even film 30 (having a thickness in a range of 20 nm to 1000 nm) over the glass-ITO substrate from Step 2, using a printing technique such as spray coating. The Step 4 is denoted by 530 in FIG. 4. ;-28 -Step 5. A transparent conductive material is deposited as a top electrode 200 onto the glass-ITO substrate as prepared in the Step 3. This transparent conductive material 200 is deposited through a range of 5 techniques such as spray coating in a case of a soluble material. The Step is denoted by 540 in FIG. 4. ;Step 6. The substrate from the Step 5 is then divided into isolated photovoltaic cells 230 ("monolithically integrated") using a scribe, namely 10 to provide electrical isolation between the photovoltaic cells 230. The Step 6 is denoted by 550 in FIG. 4. ;Step 7. The entire substrate 150 from the Step 6 is encapsulated using a transparent plastic sealant. The Step 7 is denoted by 560 in FIG. 4. ;Step 8* A glass cover 110 of same dimensions as the substrate 150 of the Step 1 is next provided; the glass cover 110 is placed over the substrate 150 from the Step 7. A gap is left between the electrodes of the substrate 150 of the Step 7 and the glass cover 110; a vacuum is established within a space provided by the gap before the photovoltaic module 100 is hermetically sealed. The Step 8 is denoted by 570 in FIG. 4.

Step 9. Peripheral edges of the photovoltaic module 100 of the Step 8 are then hermetically sealed, for example using glass laser welding as 25 described in the foregoing. The Step 9 is denoted by 580 in FIG. 4.

Referring next to FIG. 3, although construction of the photovoltaic module 100 using electrodes formed on only one of the first and second substrates 110, 150 is described in the foregoing and provides a particularly convenient method for manufacture, it will be appreciated that electrodes 200 can be provided on both the first and second substrates 110, 150, but makes manufacturing more complex because the first and second -29 -substrates 110, 150 need to be accurately mutually aligned during manufacture. FIG. 3 is an illustration of the photovoltaic module and its associated one or more photovoltaic cells 230 utilizing electrodes provided on both the first and second substrates 110, 150.

The photovoltaic cells 230 (also referred as being a "photovoltaic cell array") are, for example, manufactured to utilise an inter-penetrating blend of electron donor, electron acceptor, hole conducting or ion conducting materials as the active photon absorbing layer 160, such as dye-sensitised and organic polymer PV cells. As shown in FIG. 3, the photovoltaic module 100 is composed of a multiplicity of individual photovoltaic cells 230; there is used, on each of the first substrate 110 and the second substrate 150, an alternating array of anodes (A) and cathodes (C) as conductive current collectors 200, with the upper and lower current collectors 200 being physically isolated from each other by an (optionally continuous) active photon absorbing layer 160 between them. At least one of the conductive current collectors 200 will normally be substantially transparent in order to allow light into the photovoltaic module 100. Different materials are susceptible to being used for each of the anodes (A) and cathodes (C); alternatively, there is used a single electrode layer material in combination with a dopant or surface coating 310 to modify selectively and define the alternating anodic and cathodic regions of each electrode layer 200.

In order to create a multiplicity of interconnected individual photovoltaic cells 230, the anode (A) and cathode (C) of each photovoltaic cell 230 (on opposing sides of the photovoltaic cell) are physically separated from each other (by the photon absorbing layer 160); anode and cathode pairs of immediately adjacent cells (both on the same side of the cell) are in direct electrical contact and each anode-cathode pair is isolated electrically from each other by, for example, a physical gap in the current collectors 200.

-30 -Optionally, for simplicity of manufacture and/or visual aesthetics of the photovoltaic cell array, there is utilised a photon absorbing layer 160 between the upper and lower conductive current collectors 200, wherein the photon absorbing layer 160 is continuous and unbroken.

Alternatively, optionally, from efficiency considerations, it is feasible to physically isolate the absorber layers between each photovoltaic cell 230, for example by laser scribing of the photovoltaic cell array during manufacture, or by appropriate printing or masking techniques to create a gap.

Optionally, it is advantageous to minimise a distance that individual electrons, holes or ions have to travel to reach respective electrodes by utilising textured, or other high surface area electrodes, and/or to utilise an interpenetrating electrode network of donor 260 and acceptor 270 materials. An example of the latter case is where the single anode (A) and single cathode (C) of a single photovoltaic cell 230 (in an electrically interconnected array of such photovoltaic cells) comprise a very closely spaced and high surface area interdigitated pattern sharing the same 3-D volume within the photon absorber layer, but are nevertheless not in direct physical contact.

Using an alternating array of transparent anodes (A) and cathodes (C) on the first substrate side of a cell array and an alternating electrode array on the second substrate side of the cell array eliminates a need for any electrode 200 to penetrate the intermediate photon absorber layer. If the absorber layer is sufficiently thin, a continuous, unbroken photon absorber can be used across the cell array and efficiency losses through conduction or recombination losses between cells will be reduced, for example will be minimal. As well as enhancing visual aesthetics (e.g. through having an uninterrupted uniform tint), a continuous layer considerably simplifies cell manufacturing and relax process tolerances, for example enabling use of -31 -low-cost, high-speed dip or curtain coating processes to deposit the absorber layer. However, a disadvantage is that such a manufacturing method potentially requires the first substrate 110 and the second substrate 150 to be mutually aligned accurately during manufacture.

Embodiments of the present disclosure are capable of providing sustainable renewable energy and correspondingly reducing emissions of Carbon Dioxide into atmosphere arising from burning fossil fuels. The present invention is therefore relevant to Green Channel processing at the UKIPO.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

Claims (22)

1. -32 -CLAIMS1. A photovoltaic module (100) comprising: a first substrate (110) that, when in operation, receives input light radiation (120), wherein the first substrate (110) is at least partially transmissive for light of visible wavelengths; a second substrate (150) substrate, wherein the second substrate (150) is at least partially transmissive for light of visible wavelengths; a light-absorbing photovoltaic material arrangement (160) included between the first substrate (110) and the second substrate (150), wherein the light-absorbing photovoltaic material arrangement (160) is fabricated to provide one or more photovoltaic cells (230); and an electrode arrangement (200) in contact with the light-absorbing photovoltaic material arrangement (160) that provides collection of an 20 electrical output from the one or more photovoltaic cells (230); wherein the first substrate (110) and the second substrate (150) are directly mutually bonded to provide a hermetic seal (250) around the light-absorbing photovoltaic material arrangement (160).
2. 2. A photovoltaic module (100) of claim 1, wherein the hermetic seal (250) is provided by at least one of: (i) thermally fusing peripheral edges of the first and second substrates (110, 150) together; and (ii) by applying polymeric sealing material at the peripheral edges of the first and second substrates (110, 150) to bond them together.
3. -33 - 3. A photovoltaic module (100) of claim 1 or 2, wherein at least a part of the first substrate (110) is provided with, or composed of, at least one material that reduces transmission of the input light radiation (120) through the first substrate (110) of at least one of: ultra-violet radiation, infra-red radiation.
4. 4. A photovoltaic module (100) of claim 1, 2 or 3, wherein the at least one of the one or more photovoltaic cells (230) includes at least one photon absorber layer and at least two conductive electrical current pick-up 10 electrodes, wherein: (i) one of the electrical current pick-up electrodes functions, when in operation, as an anode; and (ii) the other of the electrical current pick-up electrode functions as a cathode, wherein a first side of the at least one of the one or more photovoltaic cells (230) receives, when in operation, incident light and a second side of the at least one of the one or more photovoltaic cells (230), in which the conductive electrical pick-up electrodes are positioned on one side only of the at least one of the one or more photovoltaic cells (230).
5. 5. A photovoltaic module (100) as claimed in claim 4, wherein the at least one photon absorber layer transmits, when in operation, in a range of 10% to 95% of the visible light incident on the at least one of the one or more photovoltaic cells (230).
6. 6. A photovoltaic module (100) of claim 4 or 5, wherein the conductive electrical pick-up electrodes (200) are used to interconnect individual photovoltaic cells (230) together in series with sequentially alternating anodes and cathodes.
7. -34 - 7. A photovoltaic module (100) of claim 6, wherein the one or more photovoltaic cells (230) have their anodes and cathodes connected, wherein a given anode is in direct contact with only one cathode in series.
8. 8. A photovoltaic module (100) of claim 4, 5, 6 or 7, wherein an electron-blocking or hole-blocking interlayer is inserted between at least one photon absorber layer and one or both of the electrical current pick-up electrodes.
9. 9. A photovoltaic module (100) of claim 4, 5, 6 or 7, wherein the electrical current pick-up electrodes are selectively coated or doped to induce or inhibit electron or hole conducting characteristics.
10. 10. A photovoltaic module (100) of any one of claims 4 to 9, wherein the 15 anodes are in electrical contact with one of the phases in the at least one photon absorber layer, and cathodes are in electrical contact with another of the phases in the at least one photon absorber layer.
11. 11. A photovoltaic module (100) of any one of claims 4 to 10, wherein 20 the electrical current pick-up electrodes incorporate a continuous layer of a transparent conductive oxide.
12. 12. A photovoltaic module (100) of any one of claims 4 to 10, wherein the electrical current pick-up electrodes incorporate a non-continuous layer 25 (such as strips, separated by narrow gaps) of one or more transparent conductive oxides.
13. 13. A photovoltaic module (100) of any one of claims 4 to 10, wherein the electrical current pick-up electrodes incorporate a non-continuous layer of a metal or a metallic alloy.
14. -35 - 14. A photovoltaic module (100) of any one of preceding claims, wherein a first photovoltaic cell of the one or more photovoltaic cells (230) is coupled to a second photovoltaic cell of the one or more photovoltaic cells (230), and wherein the second photovoltaic cell absorbs a portion of light that is transmitted through the first photovoltaic cell.
15. 15. A photovoltaic module (100) of any one of preceding claims, wherein the first and second substrates (110, 150) are made from a transparent or translucent glass.
16. 16. A photovoltaic module (100) of any one of preceding claims, wherein the light-absorbing photovoltaic material arrangement (160) employs an organic polymer in its at least one photon absorber layer.
17. 17. A photovoltaic module (100) of claim 16, wherein the least one photon absorber layer includes a non-homogenous blend of electron donor, electron acceptor, hole-conducting and/or semiconductor phases, including materials such as organic polymers, oxides, carbon, electrolytes and catalysts.
18. 18. A photovoltaic module (100) of claim 1, 2 or 3, wherein the at least one of the one or more photovoltaic cells (230) includes at least one photon absorber layer and at least two conductive electrical current pick-up electrodes, wherein: (i) one of the electrical current pick-up electrodes functions, when in operation, as an anode; and (ii) the other of the electrical current pick-up electrode functions as a cathode, wherein a first side of the at least one of the one or more photovoltaic cells (230) receives, when in operation, incident light and a second side of the at least one of the one or more photovoltaic cells (230), in which the -36 -conductive electrical pick-up electrodes are positioned on both sides of the at least one of the one or more photovoltaic cells (230).
19. 19. A method for manufacturing a photovoltaic module (100), wherein 5 the method comprises: (i) providing a first substrate (110) that, when in operation, receives input light radiation (120), wherein the first substrate (110) is at least partially transmissive for light of visible wavelengths; (ii) providing a second substrate (150) substrate, wherein the second substrate (150) is at least partially transmissive for light of visible wavelengths; (iii) applying a light-absorbing photovoltaic material arrangement (160) onto a least one of the first substrate (110) and the second substrate (150), wherein the light-absorbing photovoltaic material arrangement (160) is fabricated to provide one or more photovoltaic cells (230); (iv) applying an electrode arrangement (200) in contact with the light-absorbing photovoltaic material arrangement (160) that provides collection of an electrical output from the one or more photovoltaic cells (230); and (v) directly mutually bonding together the first substrate (110) and the second substrate (150) to provide a hermetic seal (250) around the light-absorbing photovoltaic material arrangement (160).
20. 20. A method of claim 19, wherein the method includes providing the hermetic seal (250) by at least one of: (i) thermally fusing peripheral edges of the first and second substrates (110, 150) together; and -37 - ( ) by applying polymeric sealing material at the peripheral edges of the first and second substrates (110, 150) to bond them together.
21. 21. A method of claim 19 or 20, wherein the method further includes 5 manufacturing the light-absorbing photovoltaic material arrangement (160) using deposition from a liquid solution or a liquid suspension.
22. 22. A method of claim 21, wherein the method further includes using deposition techniques including at least one of: powder spraying, liquid spraying, dip-coating, spin-coating, curtain coating, casting, or printing.