SOLAR ENERGY AND AGROPRODUCTION STRUCTURES AND FACILITIES

Abstract

The invention concerns a transparent or semitransparent film comprising a perovskite material absorbing light within the photosynthetically active radiation (PAR) spectrum.

Claims

1-44. (canceled)

45. A transparent or semitransparent film comprising or consisting at least one perovskite material absorbing light within the photosynthetically active radiation (PAR) spectrum.

46. The film according to claim 45, wherein said perovskite material absorbs light of a wavelength below a wavelength within a range between 610 nm and 620 nm.

47. The film according to claim 45, provided on a transparent substrate, having a two dimensional or three-dimensional (curved) surface, wherein the substrate is optionally conductive.

48. The film according to claim 45, wherein the perovskite is MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3, or Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.3Br.sub.0.7).sub.3, or MA.sub.nFA.sub.1-nPb(I.sub.xBr.sub.1-x).sub.3, wherein each of x and n, independently of the other, is between 0.2 and 0.3, or Cs.sub.nFA.sub.1-nPb(I.sub.xBr.sub.1-x).sub.3 wherein n is between 0.15 and 0.25 and wherein x is between 0.2 and 0.4.

49. A device implementing a film according to claim 45.

50. The device according to claim 49, being an electrical device or a photoelectric device.

51. The device according to claim 49, wherein the photoelectric device is a photovoltaic device (cell), a sensitizer, a light harvesting device or a light concentrator.

52. The device according to claim 50, wherein the photovoltaic device is configured as a solar panel.

53. The device according to claim 52, wherein the solar panel is shaped or adapted as a roof panel.

54. A photovoltaic device comprising a film according to claim 45, the photovoltaic cell being configured to selectively convert light having a wavelength or a wavelength range of below 610 nm to electricity and to allow light of a wavelength above 610 or 620 nm to be transmitted therethrough.

55. The device according to claim 54, comprising or consisting a substrate, at least one transparent or semitransparent perovskite film according to claim 45, at least one conductive layer, optionally a scaffold structure layer, and further optionally at least one hole conductive layer.

56. The device according to claim 55, comprising: a conductive transparent substrate; the film of a perovskite material; optionally a hole transporter layer; and a metal contact.

57. The device according to claim 54, comprising a titanium oxide continuous conductive layer; and a titanium oxide particulate layer.

58. The device according to claim 57, wherein the perovskite is MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3, or Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.3Br.sub.0.7).sub.3, or MA.sub.nFA.sub.1-nPb(I.sub.xBr.sub.1-x).sub.3, wherein each of x and n, independently of the other, is between 0.2 and 0.3, or Cs.sub.nFA.sub.1-xPb(I.sub.xBr.sub.1-x).sub.3 wherein n is between 0.15 and 0.25 and wherein x is between 0.2 and 0.4.

59. An agricultural structure comprising (i) a solar panel or a photovoltaic device provided on the structure's roof and/or (ii) a roof panel or top panel being the solar panel or the photovoltaic device, the device implementing MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3, or implementing Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.3Br.sub.0.7).sub.3, or implementing MA.sub.nFA.sub.1-nPb(I.sub.xBr.sub.1-x).sub.3, wherein each of x and n, independently of the other, is between 0.2 and 0.3, or implementing Cs.sub.nFA.sub.1-nPb(I.sub.xBr.sub.1-x).sub.3 wherein n is between 0.15 and 0.25 and wherein x is between 0.2 and 0.4.

60. A solar panel implementing at least one perovskite material having an absorbance below 610 nm and transmittance above 610 or 620 nm.

61. The solar panel according to claim 60, for generating electricity, the solar panel being configured as a roof panel.

62. The solar panel according to claim 60, configured as a roof panel for agricultural enclosures.

63. A method for reducing growing temperatures in an enclosed agricultural facility, the method comprising allowing a portion of incident solar radiation to irradiate into the facility through one or more solar panels implementing a film of a perovskite material having an absorbance below 610 nm and transmittance above 610 nm to thereby filtering the incident light and reducing temperatures within the facility.

64. The method according to claim 63, wherein the one or more solar panels are positioned on the roof of the facility.

65. The method according to claim 63, wherein the one or more solar panels are roof panels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0182] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0183] FIG. 1 depicts the absorption spectrum of both chlorophyll a and chlorophyll b. The use of both together enhances the amount of absorbed light for producing energy storage assimilates.

[0184] FIGS. 2A-B provide schematic representation of (FIG. 2A) a photovoltaic device according to certain embodiments of the invention, and (FIG. 2B) an inverted architecture device where MeO-2PACz serves as the hole transport layer and the PCBM and BCP are the electron transport layer.

[0185] FIGS. 3A-B show (FIG. 3A) absorbance spectra of mixed cation perovskite at different compositions. (FIG. 3B) The absorbance of plant's pigments in the chloroplast.

[0186] FIGS. 4A-B show (FIG. 4A) current voltage curve of the solar cell having wavelength cutoff at 600 nm. (FIG. 4B) a picture taken of the solar cell with 600 nm wavelength cutoff.

[0187] FIG. 5 provides the absorbance graph for MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3 with an absorbance edge of 600 nm.

[0188] FIG. 6 provides a J-V curve graph of device according to the invention.

[0189] FIG. 7 shows the voltage and efficiency stability graph for a device maintained under ambient conditions for two weeks.

[0190] FIG. 8 provides the External Quantum Efficiency (EQE) graph for a device of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Perovskite Solar Cells for Greenhouse

Substrate Preparation

[0191] 2.5 cm.sup.2 ITO glass (TEC 12-15, Automatic Research) were etched by Zn powder and HCl (37%) to achieve the desired electrode pattern. The electrodes were then cleaned by Hellmanex solution (2% in DI water, Sigma Aldrich), DI water, Acetone, and Isopropyl alcohol in an ultrasonic bath for 15 minutes each.

Perovskite Solution Preparation

[0192] A 1M solution of Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.3Br.sub.0.7).sub.3 was prepared by weighing PbBr.sub.2 (Sigma), FAI (GreatCell), and CsBr (Sigma) powders in the right stoichiometric amounts. The precursors were then dissolved in a mixture of Dimethylformamide (DMF, Acros)) and Dimethylsulfoxide (DMSO, Acros) in a ratio of 4:1, respectively. The solution was placed on a 60 C. hotplate and stirred over night before use.

Hole Transport Material (HTM) and Electron Transport Material (ETM) Solutions Preparation

[0193] The hole transport material (HTM) solution was prepared by dissolving 0.3 mg of MeO-2PACz (TCI Chemicals) in 1 mL of anhydrous ethanol (Acros). The solution was then sonicated for 10-15 minutes until it was completely clear. In order to form the electron transport material (ETM) solution a 30 mg of PC.sub.61BM (Ossila) were dissolved in 1 mL of chlorobenzene (Sigma) and stirred overnight at 60 C. before use.

Solar Cell Fabrication

[0194] The hole transport layer was prepared by spin-coating the MeO-2PACz solution at 3500 rpm for 35 seconds follow by 10 minutes annealing at 100 C. After the substrate cooled to room temperature, 100 l of perovskite solution was drop on top of it and spin coated at 1000 rpm for 10 seconds followed by 3500 for 35 seconds. 10 seconds before the end of the program 180 l of anhydrous Chlorobenzene (Sigma) were dropped on the spinning substrate to force crystallization. The perovskite layer was annealed at 100 C. for 40-60 minutes. After cooling down to room temperature 100 l of PCBM solution were dynamically spin-coated at 2000 rpm for 30 seconds and annealed at 100 C. for 10 minutes forming the electron transporting layer. A 1 mg/ml bathocuproine (BCP, Ossila) solution in isopropyl alcohol was spin-coated on top of the PCBM layer at 6000 rpm and annealed at 70 C. for 5 minutes. To complete the device a 100 nm Ag back contact was thermally evaporated in 3 steps. The first 10 nm at a rate of 0.1 A/sec, followed by 35 nm at a rate of 0.5 A/sec, and finally 55 nm at a rate of 1.1 A/sec.

Results

[0195] The perovskite band-gap can be easily tuned by changing the bromide/iodide halide ratio which affects the electronic properties of the perovskite. As can be seen in FIG. 3A the absorbance edge of the perovskite layer is shifted towards shorter wavelength when the bromide ratio getting higher. For 85% bromide ratio the absorbance edge is at 600 nm. This absorbance is in an excellent correlation to the plant's pigments absorption as presented in FIG. 3B. It can be seen that chlorophyll a (blue curve) and chlorophyll b (red curve) have two separate absorbance regions, the first at 400-525 nm and the second at 600-700 nm. Therefore, when combining between the two, the perovskite film will allow the plant to absorb the essential wavelength for the chlorophyll activity.

[0196] The mixed cation perovskite composition of Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.15Br.sub.0.85).sub.3 showed very good photovoltaic (PV) parameters as reflected from Table 1. It can be seen that the Voc is 0.95V and the Jsc is 7.7 mA/cm.sup.2 which yielded a power conversion efficiency (PCE) of 6.6%. The current voltage curve can be observed in FIG. 6. Two main reasons are responsible for this PV performance. First, the device is in an inverted architecture which based on organic ETL and HTL with better conductivity and energy bands alignment. Second, the perovskite structure composed from a mixture of FA.sup.+ (Formammidinium) and Cs.sup.+ (Cesium) which reduced the perovskite band-gap in comparison to the MA.sup.+ based perovskite. As can be seen in FIG. 4 the film has an orange-red color with some transparency. This perovskite is based on Cs.sub.0.2FA.sub.0.8Pb(I.sub.0.15Br.sub.0.85).sub.3 film that expressed a cutoff wavelength at 600 nm. The red color derives from the halide composition which based on a majority of bromide (85%). As a result, the absorbance edge is shifted towards shorter wavelengths allow more light (in longer wavelength region) to pass throughout the perovskite layer which makes it semitransparent.

[0197] Various perovskite materials may be utilized according to the invention. As disclosed herein, suitable perovskites may be identified by measuring the absorbance spectrum of the material. For example, as shown in FIG. 5, the absorbance spectrum for MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3 having an absorbance edge of 600 nm provides a good correlation to plant absorbance spectrum.

[0198] Table 1 below presents the average photovoltaic parameters for 33 devices made with MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3

TABLE-US-00001 TABLE 1 Average photovoltaic parameters of the solar cell utilizing MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3. Voc (V) Jsc (mA/cm.sup.2) Fill Factor (%) Efficiency (%) 0.95 0.29 7.7 3.2 69.9 14.2 6.6 2.7

[0199] FIG. 6 shows the J-V curve of the photovoltaic device utilizing MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3. The photovoltaic parameters of this device are summarized in Table 2.

TABLE-US-00002 TABLE 2 Photovoltaic parameters of the solar cell utilizing MA.sub.0.25FA.sub.0.75Pb(I.sub.0.25Br.sub.0.75).sub.3. Voc (V) Jsc (mA/cm.sup.2) Fill Factor (%) PCE (%) 1.2 10.3 78 9.7

[0200] Stability graphs for the device of Table 2 kept under ambient conditions for two weeks are shown in FIG. 7. It can be seen that both parameters did not show any degradation during this time. FIG. 8 shows the EQE spectra of the corresponding device which demonstrates a good agreement between the measured Jsc (by the solar simulator) to the integrated Jsc value extracted from the EQE spectra.