PHOTOVOLTAIC MODULE
20230027970 · 2023-01-26
Inventors
Cpc classification
Y02P70/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H10K71/40
ELECTRICITY
H10K85/1135
ELECTRICITY
International classification
Abstract
The invention relates to a photovoltaic module comprising a glass substrate or a substrate made of polymer material and at least two photovoltaic cells, a first photovoltaic cell and a second photovoltaic cell, on said substrate.
Claims
1. A photovoltaic module comprising: a substrate made of glass or a polymer material, at least two photovoltaic cells, a first photovoltaic cell and a second photovoltaic cell, on said substrate, each of said two photovoltaic cells comprising: i. a cathode layer of indium-tin oxide covering said substrate, ii. a first interfacial layer of zinc oxide or aluminum-doped zinc oxide, said first interfacial layer covering said cathode, iii. a photovoltaic active layer covering said first interfacial layer, and iv. a second interfacial layer comprising a polymer blend of poly(3,4-ethylenedioxythiophene) and sodium poly(styrene sulfonate), said second interfacial layer constituting the anode and covering said photovoltaic active layer, said second interfacial layer being continuous, having an organic fibrous structure and an average thickness of between 100 nm and 400 nm, the second interfacial layer of the first photovoltaic cell being in contact with the indium-tin oxide layer of the second photovoltaic cell.
2. The photovoltaic module according to claim 1, wherein said second interfacial layers have a square resistance between 100Ω/□ and 600Ω/□.
3. The photovoltaic module according to claim 1, wherein said second interfacial layers have a roughness Ra equal to or less than 5 nm.
4. The photovoltaic module according to claim 1, wherein said photovoltaic active layers comprise a polymer blend comprising methyl [6,6]-phenyl-C.sub.61-butanoate associated with poly(thieno[3,4-b]-thiophene.
5. The photovoltaic module according to claim 1, wherein said substrate is flexible.
6. The use of said photovoltaic module as defined according to claim 1 on products such as light sports equipment, strollers, packaging, particularly luxury packaging, luggage, leather goods, interior decor, electronics, point-of-sale advertising panels, personal protective equipment, gloves, toys and edutainment, furniture, sunshades, textiles, bicycles and automobiles.
7. The use of said photovoltaic module as defined according to claim 1 under radiation equal to or less than 1000 lux.
8. A method of manufacturing a photovoltaic module as defined in claim 1, comprising the following steps: a) providing a substrate made of glass or a polymer material; b) forming two indium-tin oxide layers on said substrate, both of said indium-tin oxide layers constituting the cathode of each of said photovoltaic cells; c) forming two first interfacial layers, both of said two first interfacial layers being formed on each of said indium-tin oxide layers; d) forming two active photovoltaic layers, both of said photovoltaic active layers being formed on each of said first interfacial layers; e) forming two second interfacial layers, both of said second interfacial layers being formed on each of said photovoltaic active layers and constituting the anode of each of said photovoltaic cells; said method being characterized in that steps c) through e) are each performed by depositing ink compositions by digital inkjet printing followed by heat treatment, said ink composition used in step e) comprising a polymer blend of poly(3,4-ethylenedioxythiophene) and sodium poly(styrene sulfonate).
9. The method according to claim 8, wherein a cleaning of said photovoltaic active layers is performed between steps d) and e) using a solvent selected from ethanol, butanol, methanol, isopropanol and ethylene glycol.
10. The method according to claim 8, wherein steps c) to e) are performed as follows: c) depositing by digital inkjet printing on each of the two indium-tin oxide layers a first ink composition comprising zinc oxide nanoparticles or aluminum-doped zinc oxide (AZO) nanoparticles, followed by heat treatment, to form the first two interfacial layers; d) depositing by digital inkjet printing on said first two interfacial layers a second ink composition comprising a polymer blend comprising methyl [6,6]-phenyl-C.sub.61-butanoate combined with poly(thienol[3,4-b]-thiophene) to form said two photovoltaic active layers; and e) depositing by digital inkjet printing on said two photovoltaic active layers a third ink composition comprising a polymer blend of poly(3,4-ethylenedioxythiophene) and sodium poly(styrene sulfonate), followed by heat treatment, to form said two second interfacial layers.
11. The method according to claim 10, wherein the heat treatments of steps c) to e) are annealing treatments carried out at a temperature between 70° C. and 130° C., for a time between 1 and 5 minutes.
12. The method according to claim 11, wherein the heat treatment of step c) is carried out on a hot plate at a temperature of 85° C. for 3 minutes; the heat treatment of step d) is carried out on a hot plate at a temperature of 85° C. for 2 minutes; and the heat treatment of step e) is carried out on a hot plate at a temperature of 120° C. for 1 to 5 minutes.
13. The method according to claim 8, wherein step b) of making said two indium-tin oxide layers is performed by vacuum deposition.
14. The method according to claim 10, wherein steps c) to e) of digital inkjet printing deposition are performed under ambient air atmospheres.
15. The method according to claim 10, wherein step e) of depositing by digital inkjet printing a third ink composition is performed by depositing an ink having a viscosity of less than 10 mPa.Math.s at 20° C. and comprising: between 90% and 98% by volume, relative to the total volume of said composition, of a solution of sodium poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate), and between 2% and 10% by volume relative to the total volume of an additive composition comprising: between 2% and 5% by volume relative to the total volume of all additives in the additive composition of a surfactant, between 0.8% and 2% by volume relative to the total volume of all additives in the ethylene glycol additive composition, between 0.4% and 1% by volume relative to the total volume of all additives in the ethanolamine additive composition, and between 0.8% and 2% by volume relative to the total volume of all additives in the additive composition of a glycerol.
Description
[0053] Further advantages and features of the present invention will be apparent from the following description, made with reference to the attached figures and the following examples:
[0054]
[0055]
[0056]
[0057]
[0058]
EXAMPLES
[0059] Products [0060] a glass substrate 20 coated with a discontinuous indium-tin oxide layer so that the substrate is partly covered with indium-tin oxide layers 210 and 220 which will form the cathodes of the various organic photovoltaic cells 21 and 22 described below [0061] a flexible substrate 20 made of PET (Polyethylene terephthalate) or PEN (Polyethylene 2,6-naphthalate) also coated with a discontinuous indium-tin oxide layer so that the substrate is partly covered with indium-tin oxide layers 210 and 220 which will form the cathodes of the various organic photovoltaic cells 21 and 22 described below [0062] cleaning solvents: [0063] in the case of rigid glass substrates: deionized water, Acetone, Ethanol, Isopropanol, and [0064] in the case of flexible substrates, since they are protected by plastic films, they do not need to be cleaned as in the case of rigid substrates; [0065] first ink compositions (first interfacial layers 211 and 221 of the photovoltaic cells 21 and 22 of the photovoltaic module 10 of
[0073] The PV2000 polymer of the blend E21 or the PTB7-Th polymer of the blend E22 are present in these second ink compositions at 10 mg/mL.
[0074] The weight ratio between the PV2000 polymer of the blend E21 or the PTB7-Th polymer of the blend E22 and the PC70BM is 1:1.5
[0075] The volume ratio between the solvent O-xylene and the additive Tetralin is 97:3 in these second compositions.
[0076] A second ink composition is made by adding the solvent and the additive to the polymer blend E21 or E22 and maintaining this blend for 24 hours under stirring on a hot plate at 80° C. at a speed of 700 RPM. [0077] third ink compositions (second interfacial layers 213 and 223 of the photovoltaic cells 21 and 22 of the photovoltaic module 10 of
Tests
[0083] Roughness measurement Ra
[0084] These measurements are performed with an atomic force microscope (Nanoscope III Multimode SPM from Brucker®, used in intermittent contact mode (or “tapping mode”), with hq:nsc15 tips marketed by MiKromasch® and having a radius of curvature of 8 nm), the measurements were performed on different samples of photovoltaic cells according to the invention and according to the background art.
[0085] Layer thickness measurement
[0086] The measurement of the thickness of the printed layers is carried out by means of a DektakXT stylus profilometer marketed by BRUKER, at a scratch made with a cutter blade (thereby creating a channel having the thickness of the deposit). This is a contact profilometer that measures variations in relief by vertically moving a pointed stylus that scans the surface applying a constant contact force and reveals any unevenness. The sample is placed on a plate that allows it to move with a given speed and over a chosen distance. The thickness values presented in this patent application are the average of five measurements taken at six different points on a single step of a sample. Before taking measurements, the length of the scanned area, its duration, the force of the stylus and the measurement range must be defined.
[0087] Electrical resistivity measurement
[0088] This measurement is performed using the 4-point technique, as follows: [0089] we place the 4 points aligned far from the edges of the layer to be characterized; [0090] these 4 points are equidistant from each other; and [0091] current is generated by a current generator between the outer points, while the voltage is measured between the inner points. The ratio of the measured voltage to the current flowing through the sample gives the resistance of the section between the inner points.
[0092] Viscosity measurement:
[0093] The viscosity of a fluid is manifested by its resistance to deformation or relative sliding of its layers. During the flow of a viscous fluid in a capillary tube for example, the speed of the molecules (v) is highest in the axis of the tube and decreases until it approaches zero at the wall, while between the layers a relative sliding develops; hence the appearance of tangential forces of friction. The tangential forces, in fluids, depend on the nature of the fluid considered and the regime of its flow.
[0094] The viscometer used is of the Ubbelhode type; it is placed in a thermostat maintained at a constant temperature (25° C. in our case study). We measure the flow time of a constant volume V defined by two reference marks (M1 and M2) located on either side of a small tank atop the capillary.
[0095] Aging measurement:
[0096] Aging under permanent light soaking and thermal aging at 85° C.
[0097] Morphology characterization:
[0098] AFM (Atomic Force Microscope) measurements to reproduce the surface topography and TEM (Transmission Electron Microscopy) to validate the crystalline character of the materials as well as the sizes of the nanoparticles present in the layers.
[0099] Conversion efficiency
[0100] The conversion efficiency is the ratio of the generated power and the power of the incident radiation under indoor radiation. The internal measuring bench consists of an insulated enclosure in which the characterizations of the organic photovoltaic cells and modules are carried out. A spectrometer is used to measure the incident luminous flux (from different light sources such as LED, neon, halogen and compact fluorescent lamps) in W/m.sup.2 and Lux. Measurements are also made with a Keithley 2450 source meter (20 mV-200 V, 10 nA-1 A).
Example 1: Obtaining a First Example of a First Ink Composition E11 for First Interfacial Layer 211 and 221
1.1. Synthesis of ZnO by the Polyol Technique.SUP.[4]
[0101] Equipment used:
[0102] Two round-bottom flasks, Bromine column, Oil bath, Argon bottle, syringe filter, heating plate and magnetic stirrer, ultrasonic bath, Ardeje A100® printer, Ardeje OD100® printer, print head of the following brands: KONICA®, RICOH®.
[0103] Procedure: [0104] First, a quantity of 2.207 g KOH is weighed into a 250 mL flask. Then 115 mL of methanol is added. In another larger flask, 4.101 g of zinc acetate is added with 210 mL of methanol under stirring and then 115 mL of water is added. [0105] Then, this large flask is fixed in an oil (or water) bath under stirring and argon at 60° C. on a hot plate. [0106] In addition, KOH is dissolved in an ultrasonic bath and then added dropwise to the flask. [0107] A change of color from transparent to opaque is observed. After a few minutes, the solution becomes transparent again. [0108] The blend is then stirred for another 3 hours, after which a white suspension of ZnO has formed.
1.2 Manufacture of Ink E11 from Synthesized ZnO Nanoparticles [0109] The zinc oxide ZnO obtained from the Polyol technique in Example 1.1 is cooled in a cold bath and the ZnO particles are separated by centrifugation (12 min and 7800 rpm) and dispersed in butanol using ethylene glycol as a surfactant. [0110] An ink E11 of ZnO particles with a nanoparticle concentration of 4 mg/mL is obtained. [0111] Before inkjet printing, the ink E11 is pre-filtered with a 0.45 micrometer cellulose acetate (CA) filter.
Example 2: Obtaining a Second Example of a First Ink Composition E12 for First Interfacial Layer 211 and 221
[0112] We use the aluminum-doped zinc oxide (AZO) nanoparticle ink marketed by the GENES′INK® company in the following way: before inkjet printing, the ink is first placed in an ultrasound bath for 2 minutes at room temperature, then filtered with a 0.45 micrometer cellulose acetate filter. The ink E12 is obtained.
Example 3: Obtaining a Third Example of a First Ink Composition E13 for First Interfacial Layer 211 and 221
3.1 Synthesis of AZO Nanoparticles
[0113] This synthesis is done by the following protocol, according to the one described in the scientific publication.sup.[3]: [0114] Zinc acetate, aluminum isopropylate and distilled water are introduced into a flask containing anhydrous ethanol. [0115] After heating at 80° C. for 30 minutes, potassium hydroxide dispersed in ethanol is added dropwise to the flask while heating at 80° C. for 16 hours: AZO nanoparticles are thus synthesized. [0116] These nanoparticles are then separated from the solution by centrifugation and dispersed in an alcohol-based solvent using ethanolamine (EA). [0117] By this method, AZO NC nanoparticles (acronym for: “Aluminum-Doped Zinc Oxide nano-crystals”) at Al doping levels ranging from 0% (undoped baseline) up to 0.8 at % were produced by varying the initial ratio of aluminum isopropylate precursor to zinc acetate, and keeping all other parameters constant.
3.2 Method of Manufacturing Ink E12 from Synthesized AZO Nanoparticles [0118] The AZO obtained from the Polyol technique in Example 3.1 is cooled in a cold bath and the AZO particles are separated by centrifugation (12 min and 7800 rpm) and dispersed in butanol using ethylene glycol as a surfactant. [0119] An ink E12 of AZO particles with a nanoparticle concentration of 2 mg/mL is obtained. [0120] Before inkjet printing, the ink E12 is pre-filtered with a 0.45 micrometer cellulose acetate (CA) filter.
Example 4: Obtaining Second Ink Compositions E21 and E22 for Photovoltaic Active Layer 212 and 222
[0121] Depending on whether PC70BM is used in combination with PV2000 or PC70BM in combination with PTB7-Th, the ink compositions E21 and E22 are obtained respectively, the compositions of which are detailed in Table 1 below:
TABLE-US-00001 TABLE 1 Composition E21 E22 PC70BM 15 mg 15 mg PTB7-Th 10 mg PV2000 10 mg O-xylene 1 mL 1 mL Tetralin 60 microliters 60 microliters
[0122] The ink composition E21 is obtained as follows: [0123] 10 mg PTB7-th blended with 15 mg PC70BM (corresponding to a 1:1.5 mass ratio) in 1 milliliter of o-xylene and 60 microliters of tetralin. [0124] The blend is put under magnetic stirring on a hot plate at 80° C. for 24 hours. [0125] Before printing, the ink is pre-filtered with a 0.45 micrometer AC filter. [0126] The printed layers then undergo thermal annealing on a hot plate at 85° C. for 2 minutes.
[0127] The ink composition E22 is obtained as follows: [0128] 10 mg PV2000 mixed with 15 mg PC70BM (corresponding to a mass ratio of 1:1.5) in 1 milliliter of o-xylene and 60 microliters of tetralin. [0129] The blend is put under magnetic stirring on a hot plate at 80° C. for 24 hours. [0130] Before inkjet printing, the E22 ink is filtered with a 0.45 micrometer AC filter. [0131] After inkjet printing of E12 or E22, photovoltaic active layers are obtained which, once printed, are subjected to thermal annealing on a hot plate at 85° C. for 2 minutes.
Example 5: Obtaining Third Ink Compositions E31 and E32 for Second Interfacial Layers 213 and 223
[0132] These third ink compositions E31 and E32 for second interfacial layers 213 and 223 are obtained as follows:
[0133] PEDOT:PSS is filtered with a 0.45 μm filter;
[0134] 500 μl Triton X-100 (a) is mixed with 200 μl Ethylene Glycol (b), 200 μl Glycerol (c) and 100 μl Ethanolamine (d) in 9 mL deionized water (e); [0135] the blend thus obtained is put under magnetic stirring at 50° C. on a hot plate for 30 minutes, then under magnetic stirring at room temperature for 20 minutes; [0136] the initially filtered PEDOT:PSS is mixed with the blend thus obtained after stirring, in the following proportions: 30 μl of the blend of 3 additives in deionized water for 1 mL of
[0137] PEDOT:PSS; the resulting blend (with PEDOT:PSS) is placed under magnetic stirring on a hot plate at room temperature for at least 1 hour; and [0138] the final solution thus obtained E31 is degassed for 3 to 5 minutes in an ultrasonic bath before printing.
[0139] Depending on whether PEDOT:PSS IJ1005 or PEDOT:PSS ORGACON S315 is used, the ink compositions E31 and E32 are obtained, respectively, whose compositions are detailed in the two tables 2 and 3 below:
TABLE-US-00002 TABLE 2 Solution X Composition (a + b + c + d) a-Triton x-100 a 500 μL b-Ethylene Glycol b 200 μL c-Glycerol c 200 μL d-Ethanolamine d 100 μL e-Deionized water e 9 mL
TABLE-US-00003 TABLE 3 Composition E31 E32 IJ1005 1 mL Orgacon S315 1 mL Solution X 30 μL 30 μL a) + b) + c) + d)
Example 6: Obtaining Examples of Photovoltaic Modules According to the Invention
[0140] OPV cells according to the invention are produced according to the following method:
[0141] For rigid substrates: [0142] Cleaning the rigid glass substrate with structured ITO layer by successive soaking in 4 different cleaning baths: [0143] Bath 1: Deionized water at 20-40° C. for 10-15 minutes, [0144] Bath 2: Acetone at 20-40° C. for 10-15 minutes, [0145] Bath 3: Ethanol at 20-40° C. for 10-15 minutes, [0146] Bath 4: Isopropanol at 20-40° C. for 10-15 minutes; [0147] Printing ink E11, E12, or E13 on each of the indium tin oxide layers 210 and 220 followed by annealing at 85° C. for 5 minutes to obtain the first interfacial layers 211 and 221; [0148] Printing ink E21 or E22 on each of the first interfacial layers 211 and 221 followed by annealing at 85° C. for 2 minutes to obtain the active layer 212 and 222; [0149] Cleaning the active layer 212 and 222 with an alcohol (Ethanol, Butanol, Isopropanol); [0150] Printing the ink E31 or E32 on each of the active layers 212 and 222, followed by annealing at 120° C. for 2 minutes so as to have a second interfacial layer 213 and 223 with a thickness of between 100 and 400 nm, in particular about 350 nm, the second interfacial layer 213 of the first photovoltaic cell 21 being in contact with the indium-tin oxide layer 220 of the second photovoltaic cell 22; [0151] Cleaning the second interfacial layer 213 and 223 with an alcohol (Ethanol, Butanol, Isopropanol) to improve the conductivity of the second interfacial layer 213 and 223.
[0152] For flexible substrates: [0153] The ITO/PET substrate is protected by two plastic films on both sides: [0154] this substrate is glued with double-sided tape to a glass slide of the same size; [0155] The plastic film covering the ITO side of the substrate is then removed; [0156] Printing ink E11 (or E12) on each of the indium tin oxide layers 210 and 220 followed by annealing at 85° C. for 5 minutes to obtain the first interfacial layers 211 and 221; [0157] Printing ink E21 or E22 on each of the first interfacial layers 211 and 221 followed by annealing at 85° C. for 2 minutes to obtain the active layer 212 and 222; [0158] Cleaning the active layer 212 and 222 with an alcohol (Ethanol, Butanol, Isopropanol); [0159] Printing the ink E31 or E32 on each of the active layers 212 and 222, followed by annealing at 120° C. for 2 minutes so as to have a second interfacial layer 213 and 223 with a thickness of between 100 and 400 nm, in particular about 350 nm, the second interfacial layer 213 of the first photovoltaic cell 21 being in contact (the contact is designated by the reference 30 in
[0162] At the end of the manufacturing method, a photovoltaic module 10 is obtained comprising the following organic photovoltaic cells 21 and 22, which are summarized in Table 4 below and which then comprise a second interfacial layer 213 and 223 as an anode which has a micrometric organic fiber structure.
TABLE-US-00004 TABLE 4 Cleaning OPV cells Composition of the Composition of the Active Composition of the of the according to first interfacial active photovoltaic layer second interfacial interfacial the invention layer 211 and 221 layer 212 and 222 cleaning layer 213 and 223 layer C1 E11 E21 Yes E31 yes C2 E12 E21 Yes E31 yes C3 E11 E22 Yes E31 yes C4 E12 E22 Yes E31 yes C5 E11 E21 Yes E32 yes C6 E12 E21 Yes E32 yes C7 E11 E22 Yes E32 yes C8 E12 E22 Yes E32 yes
Example 7: Obtaining Examples of Background Art/Control Modules
[0163] Photovoltaic modules comprising OPV cells in accordance with the background art are produced according to the following method:
1) ITO substrates (purchased from Lumtec®, 15 Ohm sq-1) were carefully cleaned by sonication in deionized water, acetone, ethanol and then in IPA (isopropanol) (10 minutes per bath);
2) A solution of ZnO (or AZO) nanoparticles in IPA and 0.2% (v/v) ethanolamine was deposited by centrifugation (a.k.a. spin coating) at 1500 rpm for 1 min and dried at 80° C. for 5 min on a hot plate;
3) PTB7-Th (or PV2000) and PC70BM are mixed with a mass ratio of 1:1.5 in o-xylene as solvent and tetralin as additive with a polymer concentration of 10 mg/mL (the ratio between solvent and additive is 97:3 v/v). A layer with a nominal thickness of 90-100 nm was deposited by spin coating at 2700 rpm for 2 minutes;
4) A thin layer of poly (3,4-PEDOT:PSS) (S315) was deposited by spin coating on the organic layer at the speed of 3000 rpm for 60 s, then heated on a hot plate at 120° C. for 5 minutes;
5) For the anode, samples were placed in an MBRAUN evaporator inside a glove box, in which Al metal electrodes (100 nm) were thermally evaporated under a pressure of 2×10-7 Torr through a mask.
6) making a photovoltaic module comprising such organic photovoltaic cells and wherein the anode of one photovoltaic cell adjacent to another is in contact with the indium-tin oxide layer of the latter to ensure ohmic contact between each of the organic photovoltaic cells of the photovoltaic module.
[0164] It should also be noted that
Example 8: Characterization of the OPV Cells Obtained in Examples 6 and 7
[0165] The various photovoltaic modules comprising the OPV cells, according to the invention, have been characterized according to the tests indicated above and the results of these characterizations in Table 5 below.
TABLE-US-00005 TABLE 5 Light Filling OPV cells according intensity Irradiance factor Yield to the invention in lux in mW/cm.sup.2 in % as a % C1 1000 0.3 68 16.5 C2 1000 0.3 72 18.2 C3 1000 0.3 69 16.9 C4 1000 0.3 73 20.1 C5 1000 0.3 64 14.5 C6 1000 0.3 70 15.6 C7 1000 0.3 65 14.7 C8 1000 0.3 71 16.1
[0166] The OPV cells according to the invention C1 to C8 show that the problem of printing both the ETL (electron transport layer) and the anode layer made of PEDOT-PSS material, of a photovoltaic cell is solved. In particular, such cells are advantageous when subjected to low radiation, especially indoor radiation. It is thus possible to produce a photovoltaic module 10 comprising several organic photovoltaic cells 21 and 22 each composed of 3 layers printed on a first transparent conductive electrode present on the flexible plastic or rigid glass substrate, or composed of 4 layers printed on a flexible plastic or rigid glass substrate free of any material.
[0167] The invention consists of formulating a PEDOT-PSS solution that is compatible with the inkjet printing method and that has electrical conductivity characteristics that are sufficient, in particular, to dispense with the application of an anode to the second interfacial layer so that the second interfacial layer is itself the anode. This formulation allows us to use a high conductivity PEDOT-PSS, which is traditionally used in the HTL (hole transport layer), to obtain a layer that is both an ETL and an anode layer.
[0168] The inkjet printing method combined with this formulation allows us to control the thickness of the printed layer, to optimize the electrical and optical characteristics of the material, as well as the structure of the second interfacial layer with the realization of an organic fibrous amorphous crystalline structure, having in particular organic fibers essentially oriented substantially vertically to promote the transport of the charges. The conversion efficiencies of the modules made using the present invention remain unique to date.
Comparison:
[0169] Thus, a photovoltaic module designated “Margent” (M-silver) was manufactured. This Margent module comprises several cells C1 above indicated on which have been further applied a silver-based anode having a thickness of the order of 120 nm and an electrical resistivity of the order of 2.5 μΩ.Math.cm as shown in the bottom figure of
TABLE-US-00006 TABLE 6 Open Short Light circuit circuit Maximum voltage Maximum current Maximum power Filling intensity voltage current generated by the generated by the generated by the factor in lux (in V) (in μA) module (in V) module (in μA) module (in μW) (in %) Cargent 200 2.41 23 1.78 11.21 19.9 36 500 2.68 73 2.36 32.33 76.29 39 1000 3.11 157 2.45 87.6 214.62 44 5000 4.21 1780 3.02 1191 3596.82 48 10000 4.42 4100 3.13 3068.5 9604.4 53 100,000 4.69 31400 4.175 20450 85378.75 58 (equivalent to AM 1.5)
[0170] By way of comparison, a photovoltaic module M1 according to the invention and comprising several photovoltaic cells C1 mentioned above has been manufactured. Cell C1 (without silver) was characterized according to the tests indicated previously and the results of these characterizations in Table 7 below.
TABLE-US-00007 TABLE 7 Open Short Maximum Light circuit circuit voltage Maximum current Maximum power Filling intensity voltage current generated by the generated by the generated by the factor in lux (in V) (in μA) module (in V) module (in μA) module (in μW) (in %) C1 200 3.475 57 2.75 48.2 132.5 67 500 3.675 140 3.00 116.6 349.8 68 1000 3.825 258 3.00 223.6 661.2 68 5000 4.125 1374 2.90 1074 3114.6 55 10000 4.275 2849 2.850 2008 5722.8 47 100,000 4.575 6950 2.73 4278 11764.5 37 (equivalent to AM 1.5)
[0171] With the help of these two tables (Tables 6 and 7), we can clearly see that the behavior of each Margent and MC1 module will be very different with these Cargent and C1 cells, which have different photovoltaic performances as shown below.
[0172] Indeed, for the structure using PEDOT:PSS as electrode (C1), the filling factors are considerably better in the case of low radiation (less than 1000 Lux) which translates into an ease of charge extraction and a low charge recombination rate. In this case, the open circuit voltage values as well as the short circuit currents are considerably better than those obtained with Cargent cells using the silver layer under the same lighting conditions (radiation lower than 1000 Lux).
[0173] Moreover, the photovoltaic performance of module M1 (silver-free structure) including C1 cells continuously degrades with increasing light level (light radiation) and becomes very low under the solar spectrum AM 1.5 (100 mW/cm2) which proves the limits of use of this structure (efficiency only under indoor conditions).
[0174] It should also be noted that the photovoltaic performances obtained in the case of the Margent structure comprising the Cargent cells tend in an opposite direction (according to the luminous radiation to which the cells are exposed) compared to those obtained with M1 comprising the C1 cells. Indeed, beyond 1000 lux, the photovoltaic performances obtained with the Margent structure improve to reach a maximum of 100 mW/cm.sup.2.
[0175] This is because the number of photo-generated charges under indoor conditions (radiation less than or equal to 1000 lux) is very small and therefore does not require a high conductivity electrode to ensure their collection. In this case, the PEDOT:PSS layer is able to perform the electrode function in the C1 cells of the M1 structure. In the case of a heavier lighting (radiation higher than 1000 lux) the PEDOT:PSS layer cannot transport and collect all the photo-generated charges, which causes an accumulation of charges at that layer and subsequently a degradation of the filling factors.
[0176] The silver layer of the Cargent cells is capable of collecting a large number of charges due to its high conductivity compared to PEDOT:PSS. The charge loss at the PEDOT:PSS/silver layer interface in the Cargent cells has less impact on the photovoltaic performances in the case of important lighting (radiation higher than 1000 lux according to which the number of photo-generated charges is very important) but it becomes more penalizing in the case of an interior lighting (radiation less than or equal to 1000 lux whereby the number of photo-generated charges is very weak) what explains the degradation of the performances of the Margent module exposed to radiation lower or equal to 1000 lux.
LIST OF REFERENCES
[0177] [1] Sharaf Sumaiya, Kamran Kardel, and Adel EI-Shahat. “Organic Solar Cell by Inkjet Printing—An Overview.” 53, Georgia, USA: Technologies, 2017, Vol. 5. [0178] [2] Peng, X., Yuan, J., Shen, S., Gao, M., Chesman, A. S. R., & Yin, H. (2017). “Perovskite and Organic Solar Cells Fabricated by Inkjet Printing: Progress and Prospects”, Adv. Funct. Mater. 2017, 1703704 [0179] [3] DRACULA TECHNOLOGIES' European patent application EP2960957, filed on Jun. 25, 2015 and published on Dec. 30, 2015. [0180] [4] Maisch, P., Tam, K. C., Lucera, L., Egelhaaf, H. J., Scheiber, H., Maier, E., & Brabec, C. J. (2016). “Inkjet printed silver nanowire percolation networks as electrodes for highly efficient semitransparent organic solar cells”. Organic Electronics: Physics, Materials, Applications, 38, 139-143. https://doi.org/10.1016/j.orgel.2016.08.006.