diaryloxybenzoheterodiazole compounds disubstituted with thienothienyl groups

Abstract

A diaryloxybenzoxadiazole compound having the general formula (Ia) and disubstituted with a thiophene group, wherein: -Z represents a sulfur atom, an oxygen atom, or a selenium atom; or an NR5 group, wherein R5 is selected from straight-chain or branched C1-C groups. 20 Preferably C1-C8 alkyl, or selected from optionally substituted aryl groups; -R1, R2, and R3, which may be the same or different from each other, representing hydrogen atoms; or selected from straight-chain or branched C1-C groups optionally containing heteroatoms. 20 Preferably C1-C8 alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted straight-chain or branched C1-C 20 Preferably, it contains C1-C8 alkoxy groups and -COOR6 groups, wherein R6 is selected from straight-chain or branched C1-C6 groups. 20 The preferred alkyl group is C1-C8, or cyano; R1 and R2 may optionally be combined to form a saturated, unsaturated, or aromatic cyclic or polycyclic system containing 3 to 14 carbon atoms, preferably 4 to 6 carbon atoms, together with the carbon atoms to which they are bonded, which optionally contains one or more heteroatoms, such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorus, selenium; R4 may be the same as or different from each other, selected from optionally substituted aryl groups. The diaryloxybenzoxadiazole compound having the general formula (Ia) and disubstituted with a thienophene group can be advantageously used as a spectral converter in a light-emitting solar concentrator (LSC), which in turn can improve the performance of a photovoltaic device (or solar device) on a rigid or flexible support, for example, a selection between photovoltaic cells (or solar cells) and photovoltaic modules (or solar modules). More specifically, the photovoltaic device (or solar device) can be advantageously used to construct a greenhouse.

Description

[0001] Cross Reference to Related Applications

[0002] This patent application claims priority to Italian Patent Application No. 102019000020970 filed on November 12, 2019, the entire disclosure of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present invention relates to a diaryloxybenzoheterodiazole compound disubstituted by a thienothienyl group.

[0004] More specifically, the present invention relates to a diaryloxybenzoheterodiazole compound disubstituted by a thienothienyl group having the following specific general formula (la).

[0005] Said diaryloxybenzoheterodiazole compound disubstituted by a thienothienyl group can be advantageously used as a spectral converter in a luminescent solar concentrator (LSC) which in turn is able to improve the performance of a photovoltaic device (or solar device), for example selected between a photovoltaic cell (or solar cell), a photovoltaic module (or solar module), on a rigid support or on a flexible support. More specifically, said photovoltaic device (or solar device) can be advantageously used for the construction of a greenhouse.

[0006] The present invention also relates to a luminescent solar concentrator (LSC) comprising at least one diaryloxybenzoheterodiazole compound disubstituted by a thienothienyl group, and to a photovoltaic device (or solar device) comprising said luminescent solar concentrator (LSC).

[0007] The present invention also relates to the use of said photovoltaic device (or solar device) for the construction of a greenhouse. BACKGROUND

[0008] In the prior art, one of the main limits to the use of solar radiation energy manifests itself in the ability of photovoltaic devices (or solar devices) to optimally absorb radiation with wavelengths falling within a narrow spectral range.

[0009] Since the spectral range of solar radiation extends from wavelengths of about 300 nm to wavelengths of about 2500 nm, crystalline silicon-based photovoltaic cells (or solar cells) have an optimal absorption spectrum (effective spectrum), for example in the range of 900 nm to 1100 nm, while polymer photovoltaic cells (or solar cells) are easily damaged if exposed to radiation with wavelengths lower than about 500 nm, since the induction of photodegradation phenomena becomes significant below this limit value. Typically, the efficiency of photovoltaic devices (or solar devices) of the prior art is maximum in the spectral region of 570 nm to 680 nm (yellow-orange color).

[0010] The above-mentioned drawbacks lead to a limited external quantum efficiency (EQE) of the photovoltaic device (or solar device), which is defined as the ratio between the number of electron-hole pairs generated in the semiconductor material that is part of the photovoltaic device (or solar device) and the number of photons incident on said photovoltaic device (or solar device).

[0011] In order to increase the external quantum efficiency (EQE) of the photovoltaic device (or solar device), instruments have been developed that are interposed between the source of light radiation (the sun) and the photovoltaic device (or solar device), which selectively absorb the incident radiation with wavelengths outside the effective spectrum of said photovoltaic device (or solar device), emitting the absorbed energy in the form of photons with wavelengths included in the effective spectrum. Said instruments correspond to luminescent solar concentrators (LSCs). When the photon energy re-emitted by the luminescent solar concentrator (LSC) is higher than that of the incident photons, the photoluminescence process, which includes the absorption of solar radiation and the subsequent re-emission of photons of shorter wavelength, is also called up-conversion process. Conversely, when the photon energy emitted by the luminescent solar concentrator (LSC) is lower than that of the incident photons, the photoluminescence process is called "down-conversion" process (or "down-shifting").

[0012] Typically, said luminescent solar concentrators (LSCs) consist of large panels of material transparent to solar radiation (for example, polymers or inorganic glasses), in which fluorescent compounds acting as spectral converters are dispersed or chemically linked to said material. Due to the optical phenomenon of total reflection, the radiation emitted by the fluorescent compounds is "guided" to the thin edges of the panel, where it is concentrated into the photovoltaic cells (or solar cells) placed therein. In this way, a large surface of low-cost material (photoluminescent panel) can be used to concentrate light on a small surface of high-cost material [photovoltaic cells (or solar cells)].

[0013] The fluorescent compounds can be deposited in the form of thin films on a glass support, or, as in the case of polymeric materials, they can be dispersed within a polymeric matrix. Alternatively, the polymeric matrix can be directly functionalized with fluorescent chromophores.

[0014] Ideally, in order to be used as spectral converters, the fluorescent compounds must have the following characteristics:

[0015] - high luminescence quantum efficiency (Φ) [(Φ) is defined according to the following equation (1) as the ratio between the number of photons emitted by a luminescent molecule in a unit of time and the number of photons absorbed, and its maximum value is equal to 1]:

[0016] (Φ) = number of photons emitted / number of photons absorbed (1);

[0017] - wide absorption band in the spectral region where the photovoltaic device (or solar device) is less efficient;

[0018] - high molar extinction coefficient (e);

[0019] - narrow emission band in the spectral region where photovoltaic devices (or solar devices) are more efficient;

[0020] - well separated absorption and emission bands, to avoid or minimize self-absorption phenomena.

[0021] It is known that some benzothiadiazole compounds, in particular 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB), are fluorescent compounds that can be used to build light emitting solar concentrators (LSC). For example, this type of compounds has been described in the international patent application WO 2011 / 048458 in the name of the Applicant.

[0022] 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) is characterized by an emission centered at 579 nm, a value that corresponds to an energy much higher than the minimum threshold for operating photovoltaic cells (or solar cells), for example, for the most common silicon-based photovoltaic cells (or solar cells), this threshold corresponds to a wavelength of about 1100 nm. Furthermore, its absorption of light radiation is intense and extends to a relatively wide range of wavelengths, indicating a range from 550 nm (wavelength of green radiation) to ultraviolet radiation. Finally, the Stokes shift of 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) in dichloromethane solution (CH2Cl2) is equal to 134 nm, much higher than the Stokes shift of most commercial products proposed so far for light emitting solar concentrators (LSC).

[0023] For this reason, the use of 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) makes it possible to create light emitting solar concentrators (LSC) of excellent quality.

[0024] However, 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB), although it absorbs a large part of the solar spectrum, shows a moderate absorption in the region of its greater wavelengths, corresponding to yellow and red radiation, and therefore, it is not able to convert into radiation that could be more effectively exploited by photovoltaic cells (or solar cells).

[0025] In order to find compounds that can offer comparable or even higher performance than the known benzothiadiazole compounds, in particular in terms of power generated by photovoltaic devices using these compounds, efforts have been made in the art.

[0026] For example, the international patent application WO 2016 / 046319 in the name of the Applicant, relates to disubstituted diaryloxybenzoheterodiazole compounds having general formula (I):

[0027]

[0028] wherein:

[0029] - Z represents a sulfur atom, an oxygen atom, a selenium atom; or a NR5 group, wherein R5 is selected from linear or branched C1-C 20 , preferably C1-C8 alkyl, or from optionally substituted aryl;

[0030] - R1, R2 and R3, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched C1-C 20 , preferably C1-C8 alkyl, optionally containing heteroatoms, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted linear or branched C1-C 20 , preferably C1-C8 alkoxy, optionally substituted phenoxy, -COOR6 groups, wherein R6 is selected from linear or branched C1-C 20 , preferably C1-C8 alkyl, or is a cyano group;

[0031] - or R1 and R2, can optionally be bound together to form, together with the carbon atoms to which they are bound, a saturated, unsaturated or aromatic ring or polycyclic system containing from 3 to 14 carbon atoms, preferably from 4 to 6 carbon atoms, optionally containing one or more heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorus, selenium;

[0032] - or R2 and R3, can optionally be bound together to form, together with the carbon atoms to which they are bound, a saturated, unsaturated or aromatic ring or polycyclic system containing from 3 to 14 carbon atoms, preferably from 4 to 6 carbon atoms, optionally containing one or more heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorus, selenium;

[0033] - R4, equal to or different from each other, is selected from optionally substituted aryl.

[0034] The aforementioned disubstituted diaryloxybenzoheterodiazole compounds having general formula (I) are said to be advantageously used as spectral converters in luminescent solar concentrators (LSCs), which in turn are able to improve the performance of photovoltaic devices (or solar devices) on rigid supports or on flexible supports, for example, photovoltaic devices (or solar devices) selected between photovoltaic cells (or solar cells), photovoltaic modules (or solar modules).

[0035] Applicants have now found that some of the disubstituted diaryloxybenzoheterodiazole compounds of general formula (I) described in the aforementioned international patent application WO 2016 / 046319, in particular the diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group of specific general formula (la) below, in addition to being able to provide comparable or even better performances, in particular in terms of power generated in photovoltaic devices using them, have a higher molar extinction coefficient (e) (i.e. values > 20000 Mole -1 × cm -1 ) than the known benzothiadiazole compounds. Moreover, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group have a high Stokes shift value [i.e. values > 4000 cm -1 in solution, or > 3000 cm -1 in poly(methyl methacrylate) (PMMA) films]. Moreover, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group have a higher maximum of the highest band in the emission spectrum [i.e. values > 600 nm in solution, or > 580 nm in poly(methyl methacrylate) (PMMA) films]. Moreover, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group have a higher value of the quantum luminescence efficiency (F) in solution (i.e. values > 70%). Therefore, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group are able to increase the number of photons that can be effectively converted into radiation usable by solar devices. Therefore, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group can be advantageously used for the construction of luminescent solar concentrators (LSCs). Said luminescent solar concentrators (LSCs) in turn can be advantageously used for the construction of photovoltaic devices (or solar devices) together with, for example, photovoltaic cells (or solar cells). In particular, since the absorption spectrum of said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group does not overlap with the absorption spectrum of chlorophyll, said photovoltaic devices (or solar devices) can be advantageously used for the construction of greenhouses. SUMMARY

[0036] Therefore, the object of the present application is a diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (la):

[0037]

[0038] wherein:

[0039] - Z represents a sulfur atom, an oxygen atom, a selenium atom; or a NR5 group, wherein R5 is selected from linear or branched C1-C 20 , preferably C1-C8 alkyl, or from an optionally substituted aryl group;

[0040] - R1, R2and R3, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched, optionally heteroatom-containing C1-C8alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted linear or branched C1-C8alkoxy, -COOR6group, wherein R6is selected from linear or branched C1-C8alkyl, or is a cyano group; 20 - R1, R2and R3, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched, optionally heteroatom-containing C1-C8alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted linear or branched C1-C8alkoxy, -COOR6group, wherein R6is selected from linear or branched C1-C8alkyl, or is a cyano group; 20 - R1, R2and R3, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched, optionally heteroatom-containing C1-C8alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted linear or branched C1-C8alkoxy, -COOR6group, wherein R6is selected from linear or branched C1-C8alkyl, or is a cyano group; 20 - R1, R2and R3, equal to or different from each other, represent a hydrogen atom; or are selected from linear or branched, optionally heteroatom-containing C1-C8alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted linear or branched C1-C8alkoxy, -COOR6group, wherein R6is selected from linear or branched C1-C8alkyl, or is a cyano group;

[0041] - or R1and R2, can optionally be joined together to form, together with the carbon atom to which they are bound, a saturated, unsaturated or aromatic ring or polycyclic system containing from 3 to 14 carbon atoms, preferably from 4 to 6 carbon atoms, optionally containing one or more heteroatoms, such as, for example, oxygen, sulphur, nitrogen, silicon, phosphorus, selenium;

[0042] - R4, equal to or different from each other, is selected from optionally substituted aryl.

[0043] For the purposes of the present description and of the following claims, the definition of a numerical interval always includes the extreme values, unless otherwise specified.

[0044] For the purposes of the present description and of the following claims, the term "comprising" also includes the terms "consisting essentially of or "consisting of.

[0045] For the purposes of the present description and of the following claims, the term "C1-C 20 alkyl" means a linear or branched alkyl group having from 1 to 20 carbon atoms. Specific examples of C1-C 20 alkyl groups are: methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, pentyl, 2-ethyl-hexyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl.

[0046] For the purposes of the present description and of the following claims, the term "optionally heteroatom-containing C1-C 20 alkyl" means a linear or branched, saturated or unsaturated alkyl group having from 1 to 20 carbon atoms, in which at least one hydrogen atom is replaced by a heteroatom selected from: halogen, such as, for example, fluorine, chlorine, preferably fluorine; nitrogen; sulphur; oxygen. Specific examples of optionally heteroatom-containing C1-C 20 alkyl groups are: fluoromethyl, difluoromethyl, trifluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 2,2,2-trichloroethyl, 2,2,3,3-tetrafluoropropyl, 2,2,3,3,3-pentafluoropropyl, perfluoropentyl, perfluorooctyl, perfluorodecyl, oxymethyl, thiomethyl, thioethyl, dimethylamino, propylamino, dioctylamino.

[0047] For the purposes of the present description and of the annexed claims, the term "cycloalkyl" means a cyclic alkyl group having from 3 to 10 carbon atoms. Said cycloalkyl group can be optionally substituted with one or more groups, mutually identical or different, selected from: halogen atoms, such as, for example, fluorine, chlorine, preferably fluorine; hydroxyl; C1-C 20 alkyl; C1-C 20 alkoxy; cyano; amino; nitro; aryl. Particular examples of cycloalkyl are: cyclopropyl, 1,4-dioxin, 2,2-difluorocyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, methoxycyclohexyl, fluorocyclohexyl, phenylcyclohexyl.

[0048] For the purposes of the present description and of the annexed claims, the term "aryl" means an aromatic carbocyclic group having from 6 to 60 carbon atoms. Said aryl group can be optionally substituted with one or more groups, mutually identical or different, selected from: halogen atoms, such as, for example, fluorine, chlorine, preferably fluorine; hydroxyl; C1-C 20 alkyl; halogenated C1-C 20 alkyl; C1-C 20 alkoxy; cyano; amino; nitro; aryl, phenoxy. Particular examples of aryl are: phenyl, methylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 2,4,6-triphenoxyphenyl, trimethylphenyl, trifluoromethylphenyl, diisopropylphenyl, tert-butylphenyl, methoxyphenyl, hydroxyphenyl, 2-phenoxyphenyl, 2-trifluoromethyl-6-phenoxyphenyl, fluorophenyl, pentafluorophenyl, chlorophenyl, nitrophenyl, dimethylaminophenyl, naphthyl, phenylnaphthyl, phenanthrene, anthracene.

[0049] For the purposes of the present description and of the annexed claims, the term "C1-C 20 alkoxy" means a linear or branched alkoxy group having from 1 to 20 carbon atoms. Said alkoxy group can be optionally substituted with one or more groups, mutually identical or different, selected from: halogen atoms, such as, for example, fluorine, chlorine, preferably fluorine; hydroxyl; C1-C 20 alkyl; C1-C 20 alkoxy; cyano; amino; nitro. Particular examples of C1-C 20 alkoxy are: methoxy, ethoxy, fluoroethoxy, n-propoxy, isopropoxy, n-butoxy, n-fluorobutoxy, isobutoxy, tert-butoxy, pentoxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, dodecyloxy.

[0050] For the purposes of the present description and of the appended claims, the term "cyclic or polycyclic system" means a system containing one or more saturated or unsaturated rings containing from 3 to 14 carbon atoms, optionally containing heteroatoms selected from nitrogen, oxygen, sulfur, silicon, selenium, phosphorus. Specific examples of cyclic or polycyclic systems are: thieno[3,2-b]thiophene, thiadiazole, benzothiophene, quinoxaline, pyridine.

[0051] According to a preferred embodiment of the present application, in said general formula (Ia):

[0052] - Z represents a sulfur atom;

[0053] - R1, equal to each other, represent a hydrogen atom; or are selected from optionally substituted aryl groups, preferably 2,6-dimethylphenyl, 2-phenoxyphenyl, 2,4,6- triphenoxyphenyl;

[0054] - R2and R3, equal to each other, represent a hydrogen atom;

[0055] - R4is selected from optionally substituted aryl groups, preferably phenyl.

[0056] Specific examples of diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group having general formula (Ia) useful for the purposes of the present application are reported in Table 1.

[0057] Table 1

[0058]

[0059] The diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group having general formula (Ia) of interest for the purposes of the present application can be obtained by methods known in the art, for example, operating as described in the international patent application WO 2016 / 046319 or in the Italian patent application MI2018000000667, both in the name of the Applicant and incorporated herein by reference. Further details on the methods for the preparation of said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group having general formula (Ia) can be found in the Examples hereinafter.

[0060] As mentioned above, said diaryloxybenzoheterodiazole compounds disubstituted with a thienothienyl group having general formula (Ia) can be advantageously used as spectral converters in luminescent solar concentrators (LSCs), which in turn are able to improve the performance of photovoltaic devices (or solar devices) on rigid supports or on flexible supports, such as, for example, photovoltaic cells (or solar cells), photovoltaic modules (or solar modules).

[0061] Therefore, another object of the present application is a luminescent solar concentrator (LSC) comprising at least one diaryloxybenzo-heterodiazole compound disubstituted with a thienothienyl group having general formula (la).

[0062] The diaryloxybenzo-heterodiazole compound disubstituted with a thienothienyl group having general formula (la) can be used in the luminescent solar concentrator (LSC) in the form dispersed in a polymer or in a glass, chemically bound to a polymer or to a glass, in solution, in the form of a gel.

[0063] For example, the luminescent solar concentrator (LSC) can comprise a transparent matrix, wherein the term transparent matrix means any transparent material used in the form of a support, of a binder or of a material, wherein at least one diaryloxybenzo-heterodiazole compound disubstituted with a thienothienyl group having general formula (la) is dispersed or incorporated into the support, binder or material. The material used for the matrix is transparent per se to the radiation of interest, in particular to the radiation having frequencies included in the effective spectrum of the photovoltaic device (or solar device) in which it is used, such as, for example, a photovoltaic cell (or solar cell). Therefore, the material suitable for the purposes of the present application can be chosen among the transparent materials at least under radiation having wavelengths comprised between 250 nm and 1100 nm.

[0064] The transparent matrix that can be used for the purposes of the present application can be chosen, for example, among polymeric materials or vitreous materials. The matrix is characterized by a high transparency, a high duration to heat and light. The polymeric materials that can be advantageously used for the purposes of the present application are, for example, polymethyl methacrylate (PMMA), epoxy resins, silicone resins, polyalkylene terephthalate, polycarbonate, polystyrene, polypropylene. The vitreous materials that can be advantageously used for the purposes of the present application are, for example, silicon dioxide.

[0065] In the case where the matrix is of the polymeric type, the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia) can be dispersed in the polymer of the matrix, for example, by melt dispersion, and subsequent formation of a slab comprising the polymer and the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia), for example according to the technique operation known as "casting". Alternatively, the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia) and the polymer of the matrix can be dissolved in at least one solvent, obtaining a solution, depositing the solution on a slab of the polymer, forming a film comprising the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia) and the polymer, for example, by operating with a "doctor blade" type film applicator: subsequently, the solvent is evaporated.

[0066] In the case where the matrix is of the glassy type, the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia) can be dissolved in at least one solvent, obtaining a solution, depositing the solution on a slab of the glassy matrix, forming a film comprising the at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia), for example, by operating with a "doctor blade" type film applicator: subsequently, the solvent is evaporated.

[0067] Another object of the present application is a photovoltaic device (or solar device) comprising at least one photovoltaic cell (or solar cell) and at least one luminescent solar concentrator (LSC) comprising at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia).

[0068] The photovoltaic device (or solar device) can be obtained, for example, by assembling the aforementioned luminescent solar concentrator (LSC) with at least one photovoltaic cell (or solar cell).

[0069] Another object of the present application is the use of a photovoltaic device (or solar device) comprising at least one photovoltaic cell (or solar cell) and at least one luminescent solar concentrator (LSC) comprising at least one bisaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (Ia) for the construction of a greenhouse.

[0070] According to a preferred embodiment of the present application, the aforesaid solar concentrator can be made in the form of a transparent sheet by dissolving the at least one diaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (la) and the polymer of the polymeric type matrix in at least one solvent, obtaining a solution, which is deposited on a sheet of said polymer, forming a thin film comprising said at least one diaryloxybenzoheterodiazole compound disubstituted with thienothienyl groups of general formula (la) and said polymer, for example by operating with a "doctor blade" type film applicator: subsequently, the solvent is evaporated. In the photovoltaic device (or solar device), then the sheet can be coupled to a photovoltaic cell (or solar cell). DETAILED DESCRIPTION

[0071] In order to better understand the present application and to put it into practice, below some illustrative and non-limiting examples of the present application are reported.

[0072] 4,7-di-(thiophene-2'-yl)-2,l,3-benzothiadiazole (DTB) was obtained as described in Example 1 of the international patent application WO2012 / 007834 in the name of the Applicant, the content of which is incorporated herein by reference.

[0073] In the following examples, the analytical techniques and characterization methods listed below were used.

[0074] Absorption spectra

[0075] The absorption spectra in the ultraviolet and visible (UV-Vis) (250 nm to 800 nm) of the solutions of the obtained diaryloxybenzoheterodiazole compounds disubstituted with thienothienyl groups of general formula (la) or of the polymethylmethacrylate films containing the diaryloxybenzoheterodiazole compounds disubstituted with thienothienyl groups in anhydrous dichloromethane (CH2Cl2) were acquired in transmission mode using a double-beam and double monochromator Perkin Elmer Lambda 950 spectrophotometer with a bandwidth of 2.0 nm and a step of 1.0 nm. From these spectra the ideal wavelengths for the subsequent photoluminescence measurements were determined (typically λ = 470 nm to 510 nm), corresponding to the maximum absorption region of the diaryloxybenzoheterodiazole compounds disubstituted with thienothienyl groups of general formula (la) under examination.

[0076] Molar extinction coefficient (ε)

[0077] The molar extinction coefficient (ε) of the solutions of the obtained diaryloxybenzoheterodiazole compounds disubstituted with thienothienyl groups of general formula (la) in anhydrous dichloromethane (CH2Cl2) was obtained as follows.

[0078] For this purpose, at least three solutions of each diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (Ia) are prepared, having known titration: then the UV-Visible absorption spectrum is recorded for each solution, keeping the optical path of 1 cm and reading the absorbance values with respect to the spectral position of the maximum of the absorption band measured.

[0079] The molar extinction coefficient (e) is then calculated using the Lambert-Beer law (A = ebc, where e is the molar extinction coefficient, b is the optical path, c is the molar concentration, A is the absorbance) reported by N.J. Turro, V. Ramamurthy and J.C. Scaiano in "Modern Molecular Photochemistry of Organic Molecules" (2010), ISBN 978-1-891389-25-2, pages 215-217.

[0080] Emission spectra

[0081] The emission spectrum of the obtained diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (Ia) or of the solution in anhydrous dichloromethane (CH2Cl2) of the polymethylmethacrylate film containing the obtained diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (Ia) is recorded using a Horiba Jobin Yvon Fluorolog 3 spectrofluorimeter, operating in "right angle" configuration and excited at the above selected wavelength (i.e. ideal wavelength).

[0082] Stokes shift

[0083] The Stokes shift is obtained by analyzing the absorption spectrum and the emission spectrum of each obtained diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (Ia) and is calculated as the difference between the spectral positions of the maxima of the absorption band and of the emission band, in frequency units (cm -1 ).

[0084] Luminescence quantum efficiency (Φ)

[0085] The luminescence quantum efficiency (Φ) of the obtained diaryloxybenzoheterodiazole compound disubstituted with a thienothienyl group of general formula (Ia) in anhydrous dichloromethane (CH2Cl2) is obtained using the comparative method reported by A.T.R. Williams, S.A. Winfield and J.N. Miller in "Analyst" (1983), vol. 108, page 1067.

[0086] For this purpose, 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) dissolved in anhydrous dichloromethane (CH2CI2) (0.9% by weight) was used as reference standard, with a luminescence quantum efficiency (Φ) equal to 90%.

[0087] Example 1

[0088] Synthesis of 4,7-bis-thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (DTTBOP) of formula (Ia1) (1) Synthesis of 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (a)

[0089]

[0090] (2) Synthesis of 2-tri-n-butylstannylthienothiophene of formula (b)

[0091]

[0092] In a 100 ml flask, equipped with a magnetic stirrer, a thermometer and a coolant, under inert atmosphere, phenol (Aldrich) (2.9 g; 2.8 ml, 31.6 mmol) and potassium carbonate (Aldrich) (4.4 g; 31.6 mmol) were added to a 0.3 M solution of 4,7-dibromo-5,6-difluoro-2,1,3-benzothiadiazole (Sunatech) (4.35 g; 13.2 mmol) in anhydrous N,N-dimethylformamide (Aldrich) (44 ml): the reaction mixture obtained was heated to 82°C and kept at this temperature under stirring for 12 hours. Subsequently, after the addition of 200 ml of distilled water, the precipitate obtained was recovered by filtration, washed with distilled water (30 ml) until neutral, then dried under vacuum, obtaining 6.3 g (13.2 mmol) of 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (a) (yield = 100%).

[0093] (3) Synthesis of 4,7-bis-thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (DTTBOP) of formula (Ia1)

[0094]

[0095] In a 100 ml flask, equipped with a magnetic stirrer and a thermometer, under inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (2.5 ml; 4 mmol) was added, by drop-wise addition, to a 0.12 M solution of 2,6-thienothiophene (Aldrich) (0.5 g; 3.6 mmol) in anhydrous tetrahydrofuran (Aldrich) (30 ml) at -78°C: the resulting reaction mixture was kept under stirring and the temperature was raised to -50°C in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at -78°C, tri-n-butyltin chloride (Aldrich) (1.4 g; 1.2 ml; 4.3 mmol) was added, by drop-wise addition. After 15 minutes, the flask was removed from the bath, the temperature was raised to 20°C and the reaction mixture was kept under stirring at said temperature for 12 hours. Subsequently, after adding saturated aqueous sodium bicarbonate (Aldrich) (20 ml), the reaction mixture was extracted with diethyl ether (Aldrich) (3 x 25 ml). The organic phases obtained were washed with saturated aqueous sodium bicarbonate (Aldrich) (20 ml) and then anhydrified over sodium sulfate (Aldrich). The residual solvent was removed by distillation under reduced pressure, obtaining 2-tri-n-butylstannylthienothiophene of formula (b) which was used as such.

[0096] Example 2 Synthesis of 4,7-bis-2-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (MPDTTBOP) of formula (Ib)

[0097] In a 100 ml flask, equipped with magnetic stirrer, thermometer and coolant, under inert atmosphere, 2-tri-n-butylstannylthienothiophene having formula (b), obtained as described above, was dissolved in anhydrous toluene (Aldrich) (30 ml), obtaining a solution, to which 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadi- azole having formula (a), obtained as described above, (0.71 g; 1.5 mmol) was added. After removal of the air present by 3 vacuum / nitrogen cycles, tri-dibenzylideneacetone palladium (Aldrich) (40 mg; 0.04 mmol) and tri-o-tolylphosphine (Aldrich) (50 mg; 0.16 mmol) were added, obtaining a reaction mixture which was immersed in a preheated bath at 1 10 °C and kept at said temperature under stirring for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2CI2) (Aldrich) (3x25 ml): the organic phase obtained was washed with distilled water (3x25 ml) until neutralization, then anhydrous over sodium sulfate (Aldrich). After removal of most of the residual solvent by distillation under reduced pressure, the residue obtained was added to 50 ml of methanol by dropwise addition, obtaining a precipitate which was recovered by filtration, then purified by elution on a column of silica gel [eluent: n-heptane (Aldrich) / dichloromethane (Aldrich), gradient from 9 / 1 to 8 / 2 to 6 / 4 (v / v)] obtaining 0.9 g (1.2 mmol) of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadia- zole (DTTBOP) having formula (Ia1 ) (yield = 80%).

[0098] (1) Synthesis of 2-bromothienothiophene of formula (c)

[0099] (2) Synthesis of 2-(2,6-dimethylphenyl)thienothiophene of formula (d) (3) Synthesis of 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene of formula (e)

[0100]

[0101] (4) Synthesis of 4,7-bis-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (MPDTTBOP) of formula (Ib)

[0102]

[0103] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, 2,6-dimethylphenylboronic acid (Aldrich) (0.85 g; 5.66 mmol) and 8.7 ml of a 2M aqueous solution of potassium carbonate (Aldrich) (2.4 g; 17.4 mmol) were added to a 0.17M solution of 2-bromothienothiophene of formula (c) (0.96 g; 4.35 mmol), obtained as described above, in 1,4-dioxane (Aldrich) (26 ml). After removal of the air present by 3 vacuum / nitrogen cycles, tetrakis(triphenylphosphine)palladium (Aldrich) (0.11 g; 0.095 mmol) was added, obtaining a reaction mixture which was immersed in a bath preheated to 85°C and kept at said temperature under stirring for 18 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phases obtained were washed to neutrality with distilled water (3x25 ml) and then anhydrified on sodium sulfate (Aldrich). After removal of the residual solvent by distillation under reduced pressure, the residue obtained was purified by elution on a chromatographic column of silica gel [eluent: n-heptane (Aldrich)] obtaining 0.64 g (2.6 mmol) of 2-(2,6-dimethylphenyl)thienothiophene of formula (d) (yield = 60%).

[0104] Example 3

[0105]

[0106] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, 2,6-dimethylphenylboronic acid (Aldrich) (0.85 g; 5.66 mmol) and 8.7 ml of a 2M aqueous solution of potassium carbonate (Aldrich) (2.4 g; 17.4 mmol) were added to a 0.17M solution of 2-bromothienothiophene of formula (c) (0.96 g; 4.35 mmol), obtained as described above, in 1,4-dioxane (Aldrich) (26 ml). After removal of the air present by 3 vacuum / nitrogen cycles, tetrakis(triphenylphosphine)palladium (Aldrich) (0.11 g; 0.095 mmol) was added, obtaining a reaction mixture which was immersed in a bath preheated to 85°C and kept at said temperature under stirring for 18 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phases obtained were washed to neutrality with distilled water (3x25 ml) and then anhydrified on sodium sulfate (Aldrich). After removal of the residual solvent by distillation under reduced pressure, the residue obtained was purified by elution on a chromatographic column of silica gel [eluent: n-heptane (Aldrich)] obtaining 0.64 g (2.6 mmol) of 2-(2,6-dimethylphenyl)thienothiophene of formula (d) (yield = 60%).

[0107] Synthesis of 4,7-bis-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (POPDTTBOP) of formula (Ic)

[0108]

[0109] In a 100 ml flask, equipped with a magnetic stirrer and a thermometer, under inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (1.8 ml; 2.86 mmol) was added, by drop-wise addition, to a 0.12 M solution of 2-(2,6-dimethylphenyl)thienothiophene of formula (d) (0.64 g; 2.6 mmol), obtained as described above, in anhydrous tetrahydrofuran (Aldrich) (22 ml) at -78°C: the reaction mixture obtained was kept under stirring and the temperature was raised to -50°C in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at -78°C, tri-n-butyltin chloride (Aldrich) (1 g; 0.85 ml; 3.12 mmol) was added, by drop-wise addition. After 15 minutes, the flask was removed from the bath, the temperature was raised to 20°C and the reaction mixture was kept under stirring at said temperature for 12 hours. Subsequently, after adding saturated aqueous sodium bicarbonate (Aldrich) (20 ml), the reaction mixture was extracted with diethyl ether (Aldrich) (3x25 ml). The organic phase obtained was washed with saturated aqueous sodium bicarbonate (Aldrich) (20 ml) and then anhydrified over sodium sulfate (Aldrich). The residual solvent was removed by distillation under reduced pressure, obtaining 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene of formula (e), which was used as such.

[0110] (1) Synthesis of 2-(2-phenoxyphenyl)thienothiophene of formula (f) (2) Synthesis of 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene of formula (g)

[0111] In a 100 ml flask, equipped with magnetic stirrer, thermometer and coolant, under a stream of argon, 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene, obtained as described above of formula (e), was dissolved in anhydrous toluene (Aldrich) (20 ml) obtaining a solution to which 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (a) (0.48 g; 1 mmol), obtained as described in example 1, was added. After removal of the air present by 3 vacuum / nitrogen cycles, tri-dibenzylideneacetone palladium (Aldrich) (22.2 mg; 0.02 mmol) and tri-o-tolylphosphine (Aldrich) (28 mg; 0.09 mmol) were added obtaining a reaction mixture which was immersed in a preheated bath at 110°C and kept at said temperature under stirring for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phase obtained was washed with distilled water (3x25 ml) until neutralization and subsequently anhydrified over sodium sulfate (Aldrich). After removal of the most part of the residual solvent by distillation under reduced pressure, the residue obtained was taken up in 50 ml of methanol obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a column of silica gel [eluent: n-heptane (Aldrich) / dichloromethane (Aldrich), gradient from 100 / 0 to 95 / 5 to 8 / 2 (v / v)] obtaining 0.6 g (0.75 mmol) of 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (MPDTBOP) of formula (lb) (yield = 75%).

[0112] (3) Synthesis of 4,7-bis-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (POPDTTBOP) of formula (Ic)

[0113] Example 4 Synthesis of 4,7-bis-2-(2,4,6-triphenoxylphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (2,4,6-(POP)3DTTBOP) of formula (Id)

[0114]

[0115] (1) Synthesis of 2,4,6-triphenoxyl-1-bromothienothiophene of formula (h)

[0116]

[0117] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, 2-phenoxyphenylboronic acid (Aldrich) (1.14 g; 5.33 mmol) and 8.2 ml of a 2M aqueous solution of potassium carbonate (Aldrich) (2.3 g; 16.4 mmol) were added to a 0.17M solution of 2-bromothienothiophene of formula (c) (0.9 g; 4.1 mmol), obtained as described in example 2, in 1,4-dioxane (Aldrich) (24 ml). After removal of the air present by 3 vacuum / nitrogen cycles, tetrakis(triphenylphosphine)palladium (Aldrich) (0.97 g; 0.084 mmol) was added, obtaining a reaction mixture which was immersed in a bath preheated to 85°C and kept at said temperature under stirring for 18 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phases obtained were washed with distilled water (3x25 ml) until neutral, then anhydrified on sodium sulfate (Aldrich). After removal of the residual solvent by distillation under reduced pressure, the residue obtained was purified by elution on a column of silica gel [eluent: n-heptane (Aldrich)] obtaining 0.8 g (2.6 mmol) of 2-(2-phenoxyphenyl)thienothiophene of formula (f) (yield = 63%).

[0118] (2) Synthesis of 2-(2,4,6-triphenoxylphenyl)thienothiophene of formula (i)

[0119]

[0120] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (1.8 ml; 2.86 mmol) was added, by drop-wise addition, to a 0.12 M solution of 2-(2-phenoxyphenyl)thienothiophene of formula (f) (0.8 g; 2.6 mmol), obtained as described above, in anhydrous tetrahydrofuran (Aldrich) (22 ml) at -78°C: the reaction mixture obtained was kept under stirring and the temperature was raised to -50°C in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at -78°C, tri-n-butyltin chloride (Aldrich) (1 g; 0.85 ml; 3.12 mmol) was added, by drop-wise addition. After 15 minutes, the flask was removed from the bath, the temperature was raised to 20°C and the reaction mixture was kept under stirring at said temperature for 12 hours. Subsequently, after adding saturated aqueous sodium bicarbonate (Aldrich) (20 ml), the reaction mixture was extracted with diethyl ether (Aldrich) (3x25 ml). The organic phase obtained was washed with saturated aqueous sodium bicarbonate (Aldrich) (20 ml) and then anhydrified over sodium sulfate (Aldrich). The residual solvent was removed by distillation under reduced pressure, obtaining 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene of formula (g), which was used as such.

[0121] (3) Synthesis of 2-tri-n-butylstannyl-5-(2,4,6-triphenoxylphenyl)thienothiophene of formula (1) (4) Synthesis of 4,7-bis-2-(2,4,6-triphenoxylphenyl)thienothienyl-5,6-diphenoxy-2,1,3- benzothiadiazole (2,4,6-(POP)3DTTBOP) of formula (Id)

[0122] In a 100 ml flask, equipped with magnetic stirrer, thermometer and coolant, under a stream of argon, 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene, of formula (g), obtained as described above, was dissolved in anhydrous toluene (Aldrich) (20 ml), obtaining a solution, to which 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole, of formula (a), obtained as described in example 1 (0.48 g; 1 mmol) was added. After removal of the air present by 3 vacuum / nitrogen cycles, tri-dibenzylideneacetone palladium (Aldrich) (22.2 mg; 0.02 mmol) and tri-o-tolylphosphine (Aldrich) (28 mg; 0.09 mmol) were added, obtaining a reaction mixture, which was immersed in a preheated bath at 110 °C and kept at said temperature, under stirring, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phase obtained was washed with distilled water (3x25 ml) until neutralization, then anhydrous over sodium sulfate (Aldrich). After removal of most of the residual solvent by distillation under reduced pressure, the residue obtained was taken up in 50 ml of methanol, obtaining a precipitate, which was recovered by filtration, then purified by elution on a column of silica gel [eluent: n-heptane (Aldrich) / dichloromethane (Aldrich), gradient from 100 / 0 to 95 / 5 to 8 / 2 (v / v)] obtaining 0.65 g (0.7 mmol) of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTBOP) of formula (Ic) (yield = 70%).

[0123] Example 5

[0124] 4,7-bis-thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (DTTBOP) of formula (Ia1) for the measurement of spectral properties ​

[0125]

[0126] ​

[0127]

[0128] A microwave vial was charged with: 2,4,6-trichlorophenol (Aldrich) (1.5 g; 7.6 mmol), phenol (3.4 g; 36.2 mmol), potassium carbonate (Aldrich) (5 g; 36.2 mmol) and N-methylpyrrolidine (Aldrich) (26 ml). After shaking the reaction mixture obtained, the vial was closed with the appropriate plug and inserted into a 80 ml reactor under a stream of argon: the reaction was ramped from 25°C to 220°C in 4 minutes. The reaction mixture was kept at 220°C for 3 hours in the reactor, then recovered, poured into distilled water (100 ml) and extracted with diethyl ether (Aldrich) (3 x 25 ml): the organic phase obtained was washed with distilled water (3 x 25 ml) until neutral, then anhydrified on sodium sulfate (Aldrich). After removal of the residual solvent by distillation under reduced pressure, the residue obtained was purified by elution on a chromatographic column of silica gel [eluent: n-heptane (Aldrich)] to afford 2.3 g of 2,4,6-triphenoxy-1 -bromobenzene of formula (h) (yield = 70%).

[0129] ​

[0130]

[0131] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, 2-tri-n-butylstannylthienothiophene having formula (b), obtained as described in Example 1, was added to a 0.16 M solution of 2,4,6-triphenyloxy-1- bromobenzene having formula (h), obtained as described above, in anhydrous toluene (Aldrich) (32 ml). After removal of the air present by 3 vacuum / nitrogen cycles, tri- dibenzylideneacetone palladium (Aldrich) (52.3 mg; 0.06 mmol) and tri-o- tolylphosphine (Aldrich) (65.4 mg; 0.21 mmol) were added, obtaining a reaction mixture which was immersed in a preheated bath at 110 °C and kept at said temperature under stirring for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3 x 25 ml): the organic phases obtained were washed with distilled water (3 x 25 ml) until neutral, then anhydrous over sodium sulfate (Aldrich). After removal of the most part of the residual solvent by distillation under reduced pressure, the residue obtained was taken up in 50 ml of methanol by dropwise addition, obtaining a precipitate which was recovered by filtration, then purified by elution on a column of silica gel [eluent: n- heptane (Aldrich) / dichloromethane (Aldrich), gradient from 100 / 0 to 95 / 5 to 85 / 15 (v / v)] obtaining 1 g (2 mmol) of 2-(2,4,6-triphenyloxyphenyl)thienothiophene having formula (i) (yield = 41 %).

[0132] ​ ​

[0133]

[0134] In a 100 ml flask, equipped with magnetic stirrer and thermometer, under inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (0.8 ml; 1.3 mmol) was added, by drop-wise addition, to a 0.08 M solution of 2-(2,4,6-triphenyloxyphenyl)thienothiophene of formula (i) (0.58 g; 1.17 mmol), obtained as described above, in anhydrous tetrahydrofuran (Aldrich) (15 ml) at -78°C: the reaction mixture was kept under stirring and the temperature was raised to -50°C in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at -78°C, tri-n-butyltin chloride (Aldrich) (0.46 g; 0.38 ml; 1.4 mmol) was added, by drop-wise addition. After 15 minutes, the flask was removed from the bath, the temperature was raised to 20°C and the reaction mixture was kept under stirring at said temperature for 12 hours. Subsequently, after adding saturated aqueous sodium bicarbonate (Aldrich) (20 ml), the reaction mixture was extracted with diethyl ether (Aldrich) (3 x 25 ml). The organic phase was washed with saturated aqueous sodium bicarbonate (Aldrich) (20 ml) and then anhydrified over sodium sulfate (Aldrich). The residual solvent was removed by distillation under reduced pressure to obtain 2-tri-n-butylstannyl-5-(2,4,6-triphenyloxyphenyl)thienothiophene of formula (I), which was used as such.

[0135] ​ ​

[0136] In a 100 ml flask, equipped with magnetic stirrer, thermometer and coolant, under a stream of argon, 2-tri-n-butylstannyl-5-(2,4,6-triphenyloxyphenyl)thienothiophene, obtained as described above of formula (I), was dissolved in anhydrous toluene (Aldrich) (10 ml), obtaining a solution, to which 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (IVa) (0.22 g); 0.46 mmol) obtained as described in example 1 was added. After removal of the air present by 3 vacuum / nitrogen cycles, tri- dibenzylideneacetone palladium (Aldrich) (11 mg; 0.012 mmol) and tri-o-tolylphosphine (Aldrich) (14 mg; 0.046 mmol) were added, obtaining a reaction mixture which was immersed in a preheated bath at 110°C and kept at said temperature under stirring for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH2Cl2) (Aldrich) (3x25 ml): the organic phase obtained was washed to neutrality with distilled water (3x25 ml) and then anhydrified on sodium sulfate (Aldrich). After removal of the most part of the residual solvent by distillation under reduced pressure, the residue obtained was taken up in 50 ml of methanol, obtaining a precipitate which was recovered by filtration and then purified by elution on a column of silica gel [eluent: n-heptane (Aldrich) / dichloromethane (Aldrich), gradient from 100 / 0 to 95 / 5 to 9 / 1 to 8 / 2 to 7 / 3 to 1 / 1 (v / v)] obtaining 0.4 g (0.3 mmol) of 4,7-di-2-(2,4,6-triphenyloxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (2,4,6-(POP)3DTTBOP) of formula (Id) (yield = 67%).

[0137] ​

[0138] ​ Preparation of poly(methyl methacrylate) (PMMA) films containing 2,1,3-benzothiadiazole (DTTBOP)

[0139] The measurements of the spectroscopic properties of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (Ia1 ), obtained according to the description in example 1, were carried out by dispersing said compound in a Altuglas VSUVT 100 (PMMA) polymethyl methacrylate matrix.

[0140] In this respect, 2 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 4 ml of a solution of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia1 ) in anhydrous dichloromethane (CH2CI2) (Aldrich) (concentration DTTBOP = 3.37 x 10 -5 mole / litre) were introduced into a 12 ml vial. The mixture obtained was kept in motion at 25°C for 16 hours by means of a shaking machine until the Altuglas VSUVT 100 (PMMA) polymethyl methacrylate was completely dissolved.

[0141] Subsequently, a portion of the solution thus obtained was deposited on a quartz plate (2 cm x 2 cm) having an optical surface, kept in a perfectly horizontal position. Subsequently, the plate was covered with a beaker of appropriate size, thus creating an environment almost saturated with dichloromethane (CH2CI2), so as to cause the slow evaporation of the dichloromethane (CH2CI2) so as to prevent the formation of microbubbles within the film.

[0142] After complete evaporation of the solvent (3 days), the Altuglas VSUVT 100 (PMMA) polymethyl methacrylate film containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia1 ) was peeled off from the quartz support.

[0143] On the film thus obtained, the absorption spectrum, the emission spectrum and the Stokes shift were collected, operating as described above: the values obtained are reported in Table 2.

[0144] Examples 6-8

[0145] Preparation of solutions containing compounds having general formula (Ia) for the measurement of spectral properties Preparation of films

[0146] Following the procedure described in Example 5, Altuglas VSUVT 100 (PMMA) polymethyl methacrylate films were prepared containing the compound having formula (Ib) (MPDTTBOP) prepared as in Example 2, the compound having formula (Ic) (POPDTTBOP) prepared as in Example 3 and the compound having formula (Id) (2,4,6-(POP)3DTTBOP) prepared as in Example 4, respectively (concentrations of the solutions of MPDTTBOP = 6.21 x 10 -5 mole / litre), the compound having formula (Ic) (POPDTTBOP) (concentration of the solution of POPDTTBOP = 3.83 x 10 -5 mole / litre) and the compound having formula (Id) (2,4,6-(POP)3DTTBOP) (concentration of the solution of 2,4,6-(POP)3DTTBOP = 2.24 x 10 -5 mole / litre).

[0147] On each thin film thus obtained, absorption spectra, emission spectra, and Stokes shifts were acquired, as described above: the obtained values ​​are reported in Table 2.

[0148] Table 2 reports the following in order: Example number (Example), Formula number of the compound used (Compound Formula), Example number of the compound in which it was prepared (Preparation Example), Maximum value of the lowest band in the absorption spectrum expressed in nm [λ] 最大 [(absorption)], the maximum value of the highest band in the emission spectrum, expressed in nm, [λ]. 最大 (launch)], ending with (cm) -1 ) represents the value of the Stokes displacement.

[0149] Table 2

[0150]

[0151] Example 9

[0152] Preparation of solutions containing 4,7-dithienothienyl-5,6-diphenyloxy- 2,1,3-benzothiadiazole (DTTBOP) for the measurement of spectral properties Preparation of solutions containing 4,7-dithienothienyl-5,6-diphenyloxy- 2,1,3-benzothiadiazole (DTTBOP) for the measurement of spectral properties

[0153] The 1.78 mg (2.9 × 10⁻⁶) obtained according to the description in Example 1 -3 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (mmol) of formula (Ia1) and 50 mL of anhydrous dichloromethane (CH2Cl2) were introduced into a 50 mL flask. The resulting mixture was allowed to stand at room temperature (25 °C) with stirring for 16 hours until a homogeneous solution was obtained. Subsequently, aliquots of the obtained solution were transferred to a 1 cm quartz cell, and absorption spectra, molar extinction coefficient (ε), emission spectra, and Stokes shifts were acquired as described above. The obtained values ​​are reported in Table 3.

[0154] Examples 10-12

[0155] Preparation of solutions containing compounds having general formula (Ia) for the measurement of spectral properties

[0156] Following the procedure described in Example 9, compounds having formula (Ib) (MPDTTBOP) were prepared as reported in Examples 2, 3, and 4, respectively (concentration MPDTTBOP = 6.21 × 10⁻⁶). -5 (mol / L), compounds with formula (Ic) (POPDTTBOP) (concentration POPTTBOP = 3.83 × 10⁻⁶) -5molar) and a compound of formula (Id) (2,4,6-(POP)3DTTBOP) (concentration 2,4,6-(POP)3DTTBOP = 2.24 x 10 -5 molar) in anhydrous dichloromethane (CH2Cl2).

[0157] On each of the solutions thus obtained, the absorption spectrum, the molar extinction coefficient (e), the emission spectrum and the Stokes shift were taken, operating as described above: the values obtained are reported in Table 3.

[0158] Table 3 reports, in this order: the number of the example (Example), the number of the formula relating to the compound used (Formula of the compound), the number of the example in which the compound has been prepared (Preparation Example), the maximum of the lowest band in the absorption spectrum [λ 最大 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ -1 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ -1 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ -1 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ -1 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ 最大 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ -1 (absorption)] expressed in (nm), the maximum of the highest band in the emission spectrum [λ

[0159] Table 3

[0160]

[0161] Examples 13-16

[0162] Determination of luminescence quantum efficiency (Φ) in solutions of compounds having general formula (Ia)

[0163] Using the solutions prepared as reported in Examples 9-12, containing the compounds of formula (la1) (DTTBOP), of formula (lb) (MPDTTBOP), of formula (lc) (POPDTTBOP) and of formula (Id) (2,4,6-(POP)3DTTBOP) prepared as reported in Examples 1, 2, 3 and 4, respectively, using 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) dissolved in anhydrous dichloromethane (CH2Cl2) as external standard and operating as described above, the luminescence quantum efficiency (F) was taken.

[0164] The obtained values ​​are reported in Table 4, which is reported in the following order: the example number (Example), the formula number of the compound used (Compound Formula), the example number of the compound in which it was prepared (Preparation Example), and finally the luminescence quantum efficiency (Ф) expressed as a percentage (%).

[0165] Table 4

[0166] Example Formula of the compound Preparation example Φ (%) 13 (Ia) 1 95 14 (Ib) 2 85 15 (Ic) 3 80 16 (Id) 4 72

[0167] Example 17 (comparative)

[0168] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 49.5 mg of 4,7-bis-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The resulting solution was then uniformly deposited onto a polymethyl methacrylate plate (300 mm × 90 mm × 6 mm) using a doctor blade applicator, and the solvent was allowed to evaporate in a light airflow at room temperature (25 °C) for 24 hours. The result was a transparent plate with a yellow film, and the film thickness was found to be between 100 μm and 50 μm.

[0169] Then, with a diameter of 1.2cm 2 An IXYS-KXOB22-12 photovoltaic cell with a surface area of ​​1000 is applied to one edge of a polymer plate.

[0170] Then use a power equal to 1 solar intensity (1000W / m²). 2 A light source illuminates the main surface of a polymer plate [one side coated with a film containing 4,7-di-(thiophene-2'-yl)-2,1,3-benzothiadiazole (DTB)], and the electrical power generated by the illumination effect is measured.

[0171] Power measurements (P) are performed by irradiating a portion of a 100mm × 90mm plate at an increased distance (d) from the edge where the photovoltaic cells are fixed. These measurements, performed at variable distances from the photovoltaic cells, allow for the quantification of contributions from waveguide, edge, diffusion, and self-absorption effects.

[0172] Figure 1 The curves showing the power value (P) as a function of distance (d) from the edge where the photovoltaic cell is fixed are shown. The power value (P) is expressed in mW (reported on the vertical axis), and the distance (d) is expressed in cm (reported on the horizontal axis).

[0173] It can be seen that, without edge effects, the average power generated is equal to 5.69mW.Figure 1 ).

[0174] Figure 2 The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0175] Example 18 (invention)

[0176] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 101.9 mg of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (DTTBOP) of formula (Ia1 ) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 pm and 50 pm.

[0177] The IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm 2 was then applied to one edge of the polymer plate.

[0178] The main face of the polymer plate [the one coated with the thin film containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (DTTBOP) of formula (Ia1 )] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electric power produced by the illumination effect was measured.

[0179] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0180] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) expressed in cm (reported on the abscissa) from the edge to which the photovoltaic cell was fixed is shown.

[0181] It can be seen that, in the absence of edge effects, the average power produced is equal to 2.90 mW Figure 1 ).

[0182] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0183] Example 19 (invention)

[0184] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 72.3 mg of 4,7-di-(2,6-dimethylphenyl)thienothiophenyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (lb) (MPDTTBOP) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0185] The polymethyl methacrylate plate having a length of 300 mm and a width of 90 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 A IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm

[0186] The main face of the polymethyl methacrylate plate [the one coated with the thin film containing 4,7-di-(2,6-dimethylphenyl)thienothiophenyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (lb) (MPDTTBOP)] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electrical power produced by the illumination effect was measured.

[0187] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge on which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0188] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) expressed in cm (reported on the abscissa) from the edge on which the photovoltaic cell was fixed is shown.

[0189] It can be seen that, in the absence of edge effects, the average power produced is equal to 11.39 mW Figure 1 ).

[0190] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0191] Example 20 (invention)

[0192] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 150.0 mg of 4,7-di-(2,6-dimethylphenyl)thienothiophenyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (lb) (MPDTTBOP) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0193] The polymethyl methacrylate plate having a size of 300 mm x 90 mm x 6 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m2) on the main face [the one coated with the thin film containing 4,7-di-(2,6-dimethylphenyl)thienothiophenyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (lb) (MPDTTBOP)]. 2 A IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm2was applied to one edge of the polymethyl methacrylate plate.

[0194] The polymethyl methacrylate plate having a size of 300 mm x 90 mm x 6 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m2) on the main face [the one coated with the thin film containing 4,7-di-(2,6-dimethylphenyl)thienothiophenyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (lb) (MPDTTBOP)]. 2 ) of the light source, and the electrical power produced by the illumination effect was measured.

[0195] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0196] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) in cm (reported on the abscissa) from the edge to which the photovoltaic cell was fixed is shown.

[0197] It can be seen that, in the absence of edge effects, the average power produced is equal to 13.30 mW Figure 1 ).

[0198] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of this example is reported on the abscissa) are shown.

[0199] Example 21 (invention)

[0200] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 47.8 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0201] The polymethyl methacrylate plate having a length of 300 mm and a width of 90 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m2) on the main face [the one coated with the thin film containing 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic)]. 2 A IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm2was applied to one edge of the polymethyl methacrylate plate.

[0202] The polymethyl methacrylate plate having a length of 300 mm and a width of 90 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m2) on the main face [the one coated with the thin film containing 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic)]. 2 ) and the electrical power produced by the illumination effect was measured.

[0203] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0204] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) in cm (reported on the abscissa) from the edge to which the photovoltaic cell was fixed is shown.

[0205] It can be seen that, in the absence of edge effects, the average power produced is equal to 8.84 mW Figure 1 ).

[0206] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of this example is reported on the abscissa) are shown.

[0207] Example 22 (invention)

[0208] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 86.1 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0209] The polymethyl methacrylate plate having a size of 300 mm x 90 mm x 6 mm was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 A IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm

[0210] The main face of the polymethyl methacrylate plate [the one coated with the thin film containing 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic)] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electrical power produced by the illumination effect was measured.

[0211] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge on which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguiding, edge, diffusion and self-absorption effects to be quantified.

[0212] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) expressed in cm (reported on the abscissa) from the edge on which the photovoltaic cell was fixed is shown.

[0213] It can be seen that, in the absence of edge effects, the average power produced is equal to 9.25 mW Figure 1 ).

[0214] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0215] Example 23 (invention)

[0216] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 172.2 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0217] The IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm 2 The IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm

[0218] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole (POPDTTBOP) of formula (Ic)] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electric power produced by the illumination effect was measured.

[0219] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0220] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) in cm (reported on the abscissa) from the edge to which the photovoltaic cell was fixed is shown.

[0221] It can be seen that, in the absence of edge effects, the average power produced is equal to 6.84 mW Figure 1 ).

[0222] Figure 2The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0223] Example 24 (invention)

[0224] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 241.0 mg of 4,7-di-2-(2,4,6-triphenyloxyphenyl)thienothienyl-5,6-diphenyloxy-2,1,3- benzothiadiazole of formula (Id) (2,4,6-(POP)3DTTBOP) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0225] The polymethyl methacrylate plate having a length of 1.2 cm 2 IXYS-KXOB22-12 photovoltaic cells having a surface area of 1 cm2were applied to one edge of the polymer plate.

[0226] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-2-(2,4,6-triphenyloxyphenyl)thienothienyl-5,6-diphenyloxy-2,1,3- benzothiadiazole of formula (Id) (2,4,6-(POP)3DTTBOP)] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electric power generated by the effect of the illumination was measured.

[0227] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cells were fixed. These measurements made at variable distances from the photovoltaic cells allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0228] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) expressed in cm (reported on the abscissa) from the edge to which the photovoltaic cells were fixed is shown.

[0229] It can be seen that, in the absence of edge effects, the average power produced is equal to 11.25 mW Figure 1 ).

[0230] Figure 2 The produced power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

[0231] Example 25 (invention)

[0232] 6 g of Altuglas VSUVT 100 (PMMA) polymethyl methacrylate and 158.0 mg of 4,7-di-2-(2,4,6-triphenyloxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (Id) (2,4,6-(POP)3DTTBOP) were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was then deposited uniformly on a polymethyl methacrylate plate (dimensions 300 mm x 90 mm x 6 mm) using a "doctor blade" type film applicator and the solvent was left to evaporate at room temperature (25°C) in a slight air current for 24 hours. The result was a transparent plate endowed with a yellow colour by the thin film, the thickness of which was found to be comprised between 100 μιη and 50 μιη.

[0233] The IXYS-KXOB22-12 photovoltaic cell having a surface area of 1.2 cm 2 was then applied to one edge of the polymer plate.

[0234] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-2-(2,4,6-triphenyloxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole of formula (Id) (2,4,6-(POP)3DTTBOP)] was then illuminated with a light source having a power equal to 1 solar intensity (1000 W / m 2 ) and the electric power generated by the effect of the illumination was measured.

[0235] The power measurements (P) were made by illuminating a portion of the plate having dimensions equal to 100 mm x 90 mm at increasing distances (d) from the edge to which the photovoltaic cell was fixed. These measurements made at variable distances from the photovoltaic cell allowed the contribution of waveguide, edge, diffusion and self-absorption effects to be quantified.

[0236] Figure 1 The curve relating the produced power values (P) expressed in mW (reported on the ordinate) as a function of the distance (d) expressed in cm (reported on the abscissa) from the edge to which the photovoltaic cell was fixed is shown.

[0237] It can be seen that, in the absence of edge effects, the average power produced is equal to 10.08 mW Figure 1 ).

[0238] Figure 2 The generated power values (P) expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa) are shown.

Claims

1. A diaryloxybenzoxadiazole compound having the general formula (Ia) and disubstituted with a thiophene group: in: -Z represents a sulfur atom; -R1, which are the same as each other, represent hydrogen atoms; or can be selected from aryl groups with optional substitutions; -R2 and R3 are the same and represent hydrogen atoms; -R4 is selected from aryl groups with optional substitution.

2. The diaryloxybenzoxadiazole compound disubstituted with a thiophene group according to claim 1, wherein in the general formula (Ia): -Z represents a sulfur atom; -R1, which are the same for all of them, represent hydrogen atoms; or 2,6-dimethylphenyl, 2-phenoxyphenyl, 2,4,6-triphenoxyphenyl; -R2 and R3 are the same and represent hydrogen atoms; -R4 represents a phenyl group.

3. A light-emitting solar concentrator (LSC) comprising at least one diaryloxybenzoxadiazole compound having the general formula (Ia) according to claim 1, which is disubstituted with a thiophene group.

4. A photovoltaic device comprising at least one photovoltaic cell and at least one light-emitting solar concentrator (LSC) according to claim 3.

5. The use of the photovoltaic device according to claim 4 in the construction of a greenhouse.

6. A solar energy device comprising at least one solar cell and at least one light-emitting solar concentrator (LSC) according to claim 3.

7. Use of the solar energy device according to claim 6 in the construction of a greenhouse.

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