DIARYLOXYBENZOHETERODIAZOLE COMPOUNDS DI-SUBSTITUTED WITH THIENOTHIOPHENIC GROUPS

Abstract

There is a diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia):

##STR00001##

The diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia) can be advantageously used as a spectrum converter in luminescent solar concentrators (LSCS) capable, in turn, of improving the performance of photovoltaic devices (or solar devices), selected for example, between photovoltaic cells (or solar cells), photovoltaic modules (or solar modules), either on a rigid support, or on a flexible support. More particularly, said photovoltaic devices (or solar devices) can be advantageously used in the construction of greenhouses.

Claims

1. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia): ##STR00022## wherein Z represents a sulphur atom, an oxygen atom, a selenium atom; or an NR.sub.5 group wherein R.sub.5 is selected from C.sub.1-C.sub.20 alkyl groups, linear or branched, or from optionally substituted aryl groups; R.sub.1, R.sub.2 and R.sub.3, equal to or different from each other, represent a hydrogen atom; or are selected from C.sub.1-C.sub.20 alkyl groups, linear or branched, optionally including heteroatoms, optionally substituted cycloalkyl groups, optionally substituted aryl groups, C.sub.1-C.sub.20 alkoxy groups, linear or branched, optionally substituted, —COOR.sub.6 groups wherein R.sub.6 is selected from C.sub.1-C.sub.20 alkyl groups, linear or branched, or is a cyano group; or R.sub.1 and R.sub.2, may optionally be bound together so as to form, together with the carbon atoms to which they are bound, a saturated, unsaturated, or aromatic cycle or a polycyclic system including from 3 to 14 carbon atoms, optionally including one or more heteroatoms; R.sub.4, equal to or different from each other, are selected from optionally substituted aryl groups.

2. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein in said general formula (Ia): Z represents a sulphur atom; R.sub.1, equal to each other, represent a hydrogen atom; or are selected from optionally substituted aryl groups; R.sub.2 and R.sub.3, equal to each other, represent a hydrogen atom; R.sub.4 is selected from optionally substituted aryl groups.

3. Luminescent solar concentrator (LSC) including at least one diaryloxylbenzoheterodiazole compound di-substituted with thienothiophenic groups having a general formula (Ia) according to claim 1.

4. Photovoltaic device comprising at least one photovoltaic cell, and at least one luminescent solar concentrator (LSC) according to claim 3.

5. A greenhouse, comprising at least one photovoltaic device including at least one luminescent solar concentrator (LSC) according to claim 3.

6. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein the C.sub.1-C.sub.20 alkyl groups of R.sub.5 are selected from C.sub.1-C.sub.8 alkyl groups.

7. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein the C.sub.1-C.sub.20 alkyl groups of R.sub.1, R.sub.2 or R.sub.3, are selected from C.sub.1-C.sub.8 alkyl groups.

8. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein the C.sub.1-C.sub.20 alkyl groups of R.sub.6 are selected from C.sub.1-C.sub.8 alkyl groups.

9. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein the aromatic cycle or polycyclic system of R.sub.1 and R.sub.2 include from 3 to 14 carbon atoms.

10. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 1, wherein the one or more heteroatoms of R.sub.1 and R.sub.2 are selected from the group consisting of oxygen, sulfur, nitrogen, silicon, phosphorus, and selenium.

11. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 2, wherein the optionally substituted aryl groups of R.sub.1 are selected from the group consisting of 2,6-dimethylphenyl, 2-phenoxyphenyl, and 2,4,6-triphenoxyphenyl.

12. Diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups according to claim 2, wherein the optionally substituted aryl groups of R.sub.4 are phenyl.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0066] FIG. 1 shows a curve relating to the generated power value (P) as a function of the distance (d) from the edge on which the photovoltaic cell was fixed.

[0067] FIG. 2 shows the power value obtained.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0068] In order to better understand the present disclosure and to put it into practice, some illustrative and non-limiting examples thereof are reported below.

[0069] 4,7-di-(thien-2′-yl)-2,1,3-benzothiadiazole (DTB) was obtained as described in Example 1 of the international patent application WO 2012/007834 in the name of the Applicant, whose content is incorporated herein by reference.

[0070] In the following examples, the analytical techniques and characterization methodologies listed below were used.

Absorption Spectra

[0071] The absorption spectra of the solutions in anhydrous dichloromethane (CH.sub.2Cl.sub.2) of the obtained diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups having general formula (Ia) or of the polymethylmethacrylate films containing the diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups, in the ultraviolet and in the visible (UV-Vis) (250 nm-800 nm), were acquired in transmission mode using a dual beam and dual monochromator Perkin Elmer λ950 spectrophotometer, with a 2.0 nm bandwidth and 1.0 nm step. From these spectra the ideal wavelength was identified (generally λ=470 nm-510 nm) for the subsequent photoluminescence measurements, corresponding to the zone of maximum absorption of the examined diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia).

Molar Extinction Coefficient (ε)

[0072] The molar extinction coefficient (ε) in solution of anhydrous dichloromethane (CH.sub.2Cl.sub.2) of the obtained diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups having general formula (Ia) was obtained as follows.

[0073] For this purpose, at least 3 solutions of known titre were prepared for each diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia): the UV-visible absorption spectrum was then recorded for each solution and, maintaining the optical path of 1 cm, the absorbance value relative to the spectral position of the maximum of the absorption band under examination was read.

[0074] The molar extinction coefficient (ε) was then calculated using the Lambert-Beer law (A=εbc, wherein ε is the molar extinction coefficient, b is the optical path, c is the molar concentration, A is the absorbance) according to what is 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.

Emission Spectra

[0075] The emission spectra of the solutions in anhydrous dichloromethane (CH.sub.2Cl.sub.2) of the obtained diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups having general formula (Ia) or of the polymethylmethacrylate films containing the obtained diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups having general formula (Ia) were recorded using a Horiba Jobin Yvon Fluorolog 3 spectrofluorimeter, operating in “right-angle” configuration and exciting at the selected wavelength as described above (i.e. ideal wavelength).

Stokes Shift

[0076] The Stokes shift was obtained from the analysis of the absorption and emission spectra for each obtained diaryloxybenzoheterodiazole compound di-substituted with thienothiophenic groups having general formula (Ia), and was calculated as the difference, in frequency units (cm.sup.−1), between the spectral positions of the maxima of the absorption band and of the emission band.

Luminescence Quantum Efficiency (Φ)

[0077] The luminescence quantum efficiency (Φ) of the solutions in anhydrous dichloromethane (CH.sub.2Cl.sub.2) of the obtained diaryloxybenzoheterodiazole compounds di-substituted with thienothiophenic groups having general formula (Ia) was 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.

[0078] For this purpose, 4,7-di-(thien-2′-yl)-2,1,3-benzothiadiazole (DTB) dissolved in anhydrous dichloromethane (CH.sub.2Cl.sub.2) (0.9% by weight) was used as a reference standard, luminescence quantum efficiency (Φ) equal to 90%.

EXAMPLE 1

Synthesis of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ia.SUB.1.) (DTTBOP)

[0079] ##STR00008##

(1) Synthesis of 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (a)

[0080] ##STR00009##

[0081] In a 100 ml flask, equipped with magnetic stirring, thermometer and coolant, in an inert atmosphere, phenol (Aldrich) (2.9 g; 2.8 ml, 31.6 mmoles) and potassium carbonate (Aldrich) (4.4 g; 31.6 mmoles) 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 mmoles) in anhydrous N,N-dimethylformamide (Aldrich) (44 ml): the obtained reaction mixture was heated to 82° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, after adding 200 ml of distilled water, the precipitate obtained was recovered by filtration, washed to neutral with distilled water (30 ml) and subsequently dried under vacuum, obtaining 6.3 g (13.2 mmoles) of 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (a) (yield=100%).

(2) Synthesis of 2-tri-n-butylstannylthienothiophene Having Formula (b)

[0082] ##STR00010##

[0083] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (2.5 ml; 4 mmoles) was added 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., by dripping: the reaction mixture obtained was kept under stirring and the temperature was brought to −50° C. in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at −78° C., tri-n-butylstannyl chloride (Aldrich) (1.4 g; 1.2 ml; 4.3 mmoles) was added by dripping. After 15 minutes the flask was removed from the bath, the temperature was allowed to rise to 20° C. and the reaction mixture was kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture, after addition of a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), was extracted with ethyl ether (Aldrich) (3×25 ml). The organic phase obtained was washed with a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), and subsequently anhydrified on sodium sulphate (Aldrich). The residual solvent was removed by distillation under reduced pressure obtaining 2-tri-n-butylstannylthienothiophene having formula (b) which was used as follows.

(3) Synthesis of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ia.SUB.1.) (DTTBOP)

[0084] In a 100 ml flask, equipped with magnetic stirring, thermometer and coolant, in an 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-benzothiadiazole having formula (a), obtained as described above (0.71 g; 1.5 mmoles), was added. After having removed the air present by 3 vacuum/nitrogen cycles, tris-dibenzylideneacetone dipalladium (Aldrich) (40 mg; 0.04 mmoles) and tris-o-tolylphosphine (Aldrich) (50 mg; 0.16 mmoles) were added obtaining a reaction mixture which was immersed into a pre-heated bath at 110° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed most of the residual solvent by distillation under reduced pressure, the residue obtained was added, by dripping, to 50 ml of methanol, obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a silica gel chromatographic column [eluent in 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-benzothiadiazole having formula (Ia.sub.1) (DTTBOP) (yield=80%).

EXAMPLE 2

Synthesis of 4,7-di-2-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ib) (MPDTTBOP)

[0085] ##STR00011##

(1) Synthesis of 2-bromothienothiophene Having Formula (c)

[0086] ##STR00012##

[0087] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, N-bromosuccinimide (1.95 g; 11.02 mmoles) was added to a 0.25 M solution of 2,6-thienothiophene (Aldrich) (1.4 g; 10.1 mmoles) in dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (40 ml): the reaction mixture obtained was kept, under stirring, at room temperature (25° C.), in the dark, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed the residual solvent by distillation under reduced pressure, the obtained residue was purified by elution on a silica gel chromatographic column [eluent: n-heptane (Aldrich)] obtaining 2.15 g (9.8 mmoles) of 2-bromothienothiophene having formula (c) (yield=97%).

(2) Synthesis of 2-(2,6-dimethylphenyl)thienothiophene Having Formula (d)

[0088] ##STR00013##

[0089] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, 2,6-dimethylphenylboronic acid (Aldrich) (0.85 g; 5.66 mmoles) and 8.7 ml of a 2 M aqueous solution of potassium carbonate (Aldrich) (2.4 g; 17.4 mmoles) were added to a 0.17 M solution of 2-bromothienothiophene having formula (c) obtained as described above (0.96 g; 4.35 mmoles) in 1,4-dioxane (Aldrich) (26 ml). After having removed the air present by 3 vacuum/nitrogen cycles, tetrakisphenylphosphine-palladium (Aldrich) (0.11 g; 0.095 mmoles) was added obtaining a reaction mixture which was immersed in a bath pre-heated to 85° C. and kept, under stirring, at said temperature, for 18 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed the residual solvent by distillation under reduced pressure, the obtained residue was purified by elution on a silica gel chromatographic column [eluent: n-heptane (Aldrich)] obtaining 0.64 g (2.6 mmoles) of 2-(2,6-dimethylphenyl)thienothiophene having formula (d) (yield=60%).

(3) Synthesis of 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene Having Formula (e)

[0090] ##STR00014##

[0091] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (1.8 ml; 2.86 mmoles) was added to a 0.12 M solution of 2-(2,6-dimethylphenyl)thienothiophene having formula (d) (0.64 g; 2.6 mmol) obtained as described above in anhydrous tetrahydrofuran (Aldrich) (22 ml), at −78° C., by dripping: the reaction mixture obtained was kept under stirring and the temperature was brought to −50° C. in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at −78° C., tri-n-butylstannyl chloride (Aldrich) (1 g; 0.85 ml; 3.12 mmoles) was added by dripping. After 15 minutes the flask was removed from the bath, the temperature was allowed to rise to 20° C. and the reaction mixture was kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture, after addition of a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), was extracted with ethyl ether (Aldrich) (3×25 ml). The organic phase obtained was washed with a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), and subsequently anhydrified on sodium sulphate (Aldrich). The residual solvent was removed by distillation under reduced pressure obtaining 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene having formula (e) which was used as follows.

(4) Synthesis of 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ib) (MPDTTBOP)

[0092] In a 100 ml flask, equipped with magnetic stirring, thermometer and coolant, under an argon flow, 2-tri-n-butylstannyl-5-(2,6-dimethylphenyl)thienothiophene having formula (e) 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 having formula (a), obtained as described in Example 1 (0.48 g; 1 mmole), was added. After having removed the air present by 3 vacuum/nitrogen cycles, tris-dibenzylideneacetone dipalladium (Aldrich) (22.2 mg; 0.02 mmoles) and tris-o-tolylphosphine (Aldrich) (28 mg; 0.09 mmoles) were added obtaining a reaction mixture which was immersed into a pre-heated bath at 110° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed most of the residual solvent by distillation under reduced pressure, the residue obtained was added, by dripping, to 50 ml of methanol, obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a silica gel chromatographic column [eluent in n-heptane (Aldrich)/dichloromethane (Aldrich) gradient from 100/0 to 95/5 to 8/2 (v/v)] obtaining 0.6 g (0.75 mmoles) of 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ib) (MPDTTBOP) (yield=75%).

EXAMPLE 3

Synthesis of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ic) (POPDTTBOP)

[0093] ##STR00015##

(1) Synthesis of 2-(2-phenoxyphenyl)thienothiophene Having Formula (f)

[0094] ##STR00016##

[0095] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, 2-phenoxyphenylboronic acid (Aldrich) (1.14 g; 5.33 mmol) and 8.2 ml of an 2 M aqueous solution of potassium carbonate (Aldrich) (2.3 g; 16.4 mmoles) were added to a 0.17 M solution of 2-bromothienothiophene having formula (c) obtained as described in Example 2 (0.9 g; 4.1 mmol) in 1,4-dioxane (Aldrich) (24 ml). After having removed the air present by 3 vacuum/nitrogen cycles, tetrakisphenylphosphine-palladium (Aldrich) (0.97 g; 0.084 mmoles) was added obtaining a reaction mixture which was immersed in a bath pre-heated to 85° C. and kept, under stirring, at said temperature, for 18 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed the residual solvent by distillation under reduced pressure, the obtained residue was purified by elution on a silica gel chromatographic column [eluent: n-heptane (Aldrich)] obtaining 0.8 g (2.6 mmoles) of 2-(2-phenoxyphenyl)thienothiophene having formula (f) (yield=63%).

(2) Synthesis of 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene Having Formula (g)

[0096] ##STR00017##

[0097] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (1.8 ml; 2.86 mmoles) was added to a 0.12 M solution of 2-(2-phenoxyphenyl)thienothiophene having formula (f) (0.8 g; 2.6 mmoles) obtained as described above in anhydrous tetrahydrofuran (Aldrich) (22 ml), at −78° C., by dripping: the reaction mixture obtained was kept under stirring and the temperature was brought to −50° C. in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at −78° C., tri-n-butylstannyl chloride (Aldrich) (1 g; 0.85 ml; 3.12 mmoles) was added by dripping. After 15 minutes the flask was removed from the bath, the temperature was allowed to rise to 20° C. and the reaction mixture was kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture, after addition of a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), was extracted with ethyl ether (Aldrich) (3×25 ml). The organic phase obtained was washed with a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), and subsequently anhydrified on sodium sulphate (Aldrich). The residual solvent was removed by distillation under reduced pressure obtaining 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene having formula (g) which was used as follows.

(3) Synthesis of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ic) (POPDTTBOP)

[0098] In a 100 ml flask, equipped with magnetic stirring, thermometer and coolant, under an argon flow, 2-tri-n-butylstannyl-5-(2-phenoxyphenyl)thienothiophene having 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 having formula (a), obtained as described in Example 1 (0.48 g; 1 mmole), was added. After having removed the air present by 3 vacuum/nitrogen cycles, tris-dibenzylideneacetone dipalladium (Aldrich) (22.2 mg; 0.02 mmoles) and tris-o-tolylphosphine (Aldrich) (28 mg; 0.09 mmoles) were added obtaining a reaction mixture which was immersed into a pre-heated bath at 110° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed most of the residual solvent by distillation under reduced pressure, the residue obtained was added, by dripping, to 50 ml of methanol, obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a silica gel chromatographic column [eluent in n-heptane (Aldrich)/dichloromethane (Aldrich) gradient from 100/0 to 95/5 to 8/2 (v/v)] obtaining 0.65 g (0.7 mmoles) of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ic) (POPDTTBOP) (yield=70%).

EXAMPLE 4

Synthesis of 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Id) (2,4,6-(POP) .SUB.3.DTTBOP)

[0099] ##STR00018##

(1) Synthesis of 2,4,6-triphenoxy-1-bromothienothiophene Having Formula (h)

[0100] ##STR00019##

[0101] In a microwave vial were loaded: 2,4-trifluoro-1-bromobenzene (Aldrich) (1.6 g; 7.6 mmoles), phenol (3.4 g; 36.2 mmoles), potassium carbonate (Aldrich) (5 g; 36.2 mmoles) and N-methylpyrrolidone (Aldrich) (26 ml). After shaking the reaction mixture obtained, under an argon flow, the vial was closed with the appropriate plug and inserted in an 80 ml reactor: the reaction ramp was set from 25° C. to 220° C. in 4 minutes. The reaction mixture was kept in the reactor, at 220° C., for 3 hours, subsequently recovered, poured into distilled water (100 ml) and extracted with ethyl ether (Aldrich) (3×25 ml): the organic phase obtained was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed the residual solvent by distillation under reduced pressure, the obtained residue was purified by elution on a silica gel chromatographic column [eluent: n-heptane (Aldrich)] obtaining 2.3 g of 2,4,6-triphenoxy-1-bromobenzene having formula (h) (yield=70%).

(2) Synthesis of 2-(2,4,6-triphenoxyphenyl)thienothiophene Having Formula (i)

[0102] ##STR00020##

[0103] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an 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-triphenoxy-1-bromobenzene having formula (h) (2.1 g; 5 mmoles) obtained as described above, in anhydrous toluene (Aldrich) (32 ml). After having removed the air present by 3 vacuum/nitrogen cycles, tris-dibenzylideneacetone dipalladium (Aldrich) (52.3 mg; 0.06 mmoles) and tris-o-tolylphosphine (Aldrich) (65.4 mg; 0.21 mmoles) were added obtaining a reaction mixture which was immersed into a pre-heated bath at 110° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed most of the residual solvent by distillation under reduced pressure, the residue obtained was added, by dripping, to 50 ml of methanol, obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a silica gel chromatographic column [eluent in n-heptane (Aldrich)/dichloromethane (Aldrich) gradient from 100/0 to 95/5 to 85/15 (v/v)] obtaining 1 g (2 mmoles) of 2-(2,4,6-triphenoxyphenyl)thienothiophene having formula (i) (yield=41%).

(3) Synthesis of 2-tri-n-butylstannyl-5-(2,4,6-triphenoxyphenyl) thienothiophene Having Formula (1)

[0104] ##STR00021##

[0105] In a 100 ml flask, equipped with magnetic stirring and thermometer, in an inert atmosphere, n-butyllithium (Aldrich) (1.6 M solution in hexane) (0.8 ml; 1.3 mmoles) was added to a 0.08 M solution of 2-(2,4,6-triphenoxyphenyl)thienothiophene having formula (i) (0.58 g; 1.17 mmoles) obtained as described above, in anhydrous tetrahydrofuran (Aldrich) (15 ml), at −78° C., by dripping: the reaction mixture obtained was kept under stirring and the temperature was brought to −50° C. in 3 hours. Subsequently, after placing the flask in a bath containing acetone and dry ice at −78° C., tri-n-butylstannyl chloride (Aldrich) (0.46 g; 0.38 ml; 1.4 mmoles) was added by dripping. After 15 minutes the flask was removed from the bath, the temperature was allowed to rise to 20° C. and the reaction mixture was kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture, after addition of a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), was extracted with ethyl ether (Aldrich) (3×25 ml). The organic phase obtained was washed with a saturated aqueous solution of sodium bicarbonate (Aldrich) (20 ml), and subsequently anhydrified on sodium sulphate (Aldrich). The residual solvent was removed by distillation under reduced pressure to obtain 2-tri-n-butylstannyl-5-(2,4,6-triphenoxyphenyl)thieno-thiophene having formula (1) which was used as follows.

(4) Synthesis of 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Id) (2,4,6-(POP) .SUB.3.DTTBOP)

[0106] In a 100 ml flask, equipped with magnetic stirring, thermometer and coolant, under an argon flow, 2-tri-n-butylstannyl-5-(2,4,6-triphenoxyphenyl)thienothiophene having formula (1) obtained as described above was dissolved in anhydrous toluene (Aldrich) (10 ml) obtaining a solution to which 4,7-dibromo-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (IVa) obtained as described in Example 1 (0.22 g; 0.46 mmoles), was added. After having removed the air present by 3 vacuum/nitrogen cycles, tris-dibenzylideneacetone dipalladium (Aldrich) (11 mg; 0.012 mmoles) and tris-o-tolylphosphine (Aldrich) (14 mg; 0.046 mmoles) were added obtaining a reaction mixture which was immersed into a pre-heated bath at 110° C. and kept, under stirring, at said temperature, for 12 hours. Subsequently, the reaction mixture was poured into distilled water (50 ml) and extracted with dichloromethane (CH.sub.2Cl.sub.2) (Aldrich) (3×25 ml): the obtained organic phase was washed to neutral with distilled water (3×25 ml) and subsequently anhydrified on sodium sulphate (Aldrich). After having removed most of the residual solvent by distillation under reduced pressure, the residue obtained was added, by dripping, to 50 ml of methanol, obtaining a precipitate which was recovered by filtration and subsequently purified by elution on a silica gel chromatographic column [eluent in 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 mmoles) of 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Id) (2,4,6-(POP) .sub.3DTTBOP) (yield=67%).

EXAMPLE 5

Preparation of a polymethylmethacrylate (PMMA) Film Containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ia.SUB.1.) (DTTBOP) for the Measurement of the Spectroscopic Properties

[0107] The measurement of the spectroscopic properties of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia.sub.1), obtained according to what is described in Example 1, was carried out by dispersing said compound in an Altuglas VSUVT 100 (PMMA) polymethylmethacrylate matrix.

[0108] In this regard, 2 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 4 ml of an anhydrous dichloromethane (CH.sub.2Cl.sub.2) solution (Aldrich) containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia.sub.1) (concentration DTTBOP=3.37×10.sup.−5 moles/liter) were introduced into a 12 ml vial. The mixture obtained was kept in motion, at 25° C., by means of a shaking machine, for 16 hours, until complete dissolution of the Altuglas VSUVT 100 (PMMA) polymethylmethacrylate.

[0109] Subsequently, part of the solution thus obtained was deposited on a quartz plate (2 cm×2 cm) with optical surfaces, kept in a perfectly horizontal position. Subsequently, the plate was covered with a suitably sized beaker, so that an environment almost saturated with dichloromethane (CH.sub.2Cl.sub.2) is formed, thus obtaining a slow evaporation of dichloromethane (CH.sub.2Cl.sub.2) in order to prevent the formation of micro bubbles inside the film.

[0110] Once the solvent was completely evaporated (3 days), the Altuglas VSUVT 100 (PMMA) polymethylmethacrylate film containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia.sub.1) was detached from the quartz support.

[0111] On the film thus obtained, the absorption spectrum, the emission spectrum and the Stokes shift were acquired, operating as described above: the values obtained are reported in Table 2.

EXAMPLE 6-8

Preparation of polymethylmethacrylate (PMMA) Films Containing Compounds Having General Formula (Ia) for the Measurement of Spectroscopic Properties

[0112] Following the procedure described in Example 5, Altuglas VSUVT 100 (PMMA) polymethylmethacrylate films containing the compounds having formula (Ib) (MPDTTBOP) (solution concentration of MPDTTBOP=6.21×10.sup.−5 moles/liter), formula (Ic) (POPDTTBOP) (solution concentration of POPDTTBOP=3.83×10.sup.−5 moles/liter), and formula (Id) (2,4,6-(POP) .sub.3DTTBOP) (solution concentration of 2,4,6-(POP) .sub.3DTTBOP=2.24×10.sup.−5 moles/liter), prepared as reported in Examples 2, 3 and 4, respectively, were prepared.

[0113] On each film thus obtained, the absorption spectrum, the emission spectrum and the Stokes shift were acquired, operating as described above: the values obtained are reported in Table 2.

[0114] Table 2 reports, in the order: the number of the example (Example), the number that refers to the formula of the compound used (Compound formula), the number of the example wherein the compound has been prepared (Prep. example), the value of the maximum of the lowest energy band in the absorption spectrum [λ.sub.max (abs.)] expressed in (nm), the value of the maximum of the highest energy band in the emission spectrum [λ.sub.max (emiss.)] expressed in (nm) and finally the value of the Stokes shift expressed in (cm.sup.−1)

TABLE-US-00002 TABLE 2 λ.sub.max λ.sub.max Stokes Compound Prep. (abs.) (emiss.) shift Example formula example (nm) (nm) (cm.sup.−1) 5 (Ia.sub.1) 1 474 584 3272 6 (Ib) 2 486 596 3798 7 (Ic) 3 512 622 3454 8 (Id) 4 513 624 3468

EXAMPLE 9

Preparation of a Solution Containing 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole Having Formula (Ia) (DTTBOP) for the Measurement of the Spectroscopic Properties

[0115] 1.78 mg (2.9×10.sup.−3 mmoles) of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia.sub.1) (DTTBOP), obtained according to what described in Example 1, and 50 ml of anhydrous dichloromethane (CH.sub.2Cl.sub.2) were introduced into a 50 ml flask: the mixture obtained was left, under stirring, at room temperature (25° C.), for 16 hours, until a homogeneous solution was obtained. Subsequently, an aliquot of the solution obtained was transferred to a 1 cm quartz cell, and the absorption spectrum, the molar extinction coefficient (ε), the emission spectrum and the Stokes shift were acquired, operating as described above: the values obtained are reported in Table 3.

EXAMPLE 10-12

Preparation of Solutions Containing Compounds Having General Formula (Ia) for the Measurement of the Spectroscopic Properties

[0116] Following the procedure described in Example 9, solutions in anhydrous dichloromethane (CH.sub.2Cl.sub.2) of the compounds having formula (Ib) (MPDTTBOP) (concentration MPDTTBOP=6.21×10.sup.−5 moles/liter), formula (Ic) (POPDTTBOP) (concentration POPDTTBOP=3.83×10.sup.−5 moles/liter), and formula (Id) (2,4,6-(POP) .sub.3DTTBOP) (concentration 2,4,6-(POP) .sub.3DTTBOP=2.24×10.sup.−5 moles/liter), prepared as reported in Examples 2, 3 and 4, respectively, were prepared.

[0117] On each solution thus obtained, the absorption spectrum, the molar extinction coefficient (ε), the emission spectrum and the Stokes shift were acquired, operating as described above: the values obtained are reported in Table 3.

[0118] Table 3 reports, in the order: the number of the example (Example), the number that refers to the formula of the compound used (Compound formula), the number of the example wherein the compound has been prepared (Prep. example), the value of the maximum of the lowest energy band in the absorption spectrum [λ.sub.max (abs.)] expressed in (nm), the molar extinction coefficient (ε) expressed in liters×moles.sup.−1×cm.sup.−1 (1×moles.sup.−1×cm.sup.−1) the value of the maximum of the highest energy band in the emission spectrum [λ.sub.max (emiss.)] expressed in (nm) and finally the value of the Stokes shift expressed in (cm.sup.−1).

TABLE-US-00003 TABLE 3 λ.sub.max ε λ.sub.max Stokes Compound Prep. (abs.) (1 × moles.sup.−1 × (emiss.) shift Example formula example (nm) cm.sup.−1) (nm) (cm.sup.−1) 9 (Ia.sub.1) 1 473 21228 604 4585 10 (Ib) 2 486 29467 623 4525 11 (Ic) 3 509 37668 645 4142 12 (Id) 4 510 31615 668 4638

EXAMPLES 13-16

Determination of the Luminescence Quantum Efficiency (Φ) in Solution of Compounds Having General Formula (Ia)

[0119] Using the solutions prepared as reported in Examples 9-12 containing the compounds having formula (Ia.sub.1) (DTTBOP), formula (Ib) (MPDTTBOP), formula (Ic) (POPDTTBOP) and formula (Id) (2,4,6-(POP) .sub.3DTTBOP), prepared as reported in Examples 1, 2, 3 and 4, respectively, the luminescence quantum efficiency (Φ) was acquired, using 4,7-di-(thien-2′-yl)-2,1,3-benzothiadiazole (DTB) dissolved in anhydrous dichloromethane (CH.sub.2Cl.sub.2), as external standard and operating as described above.

[0120] The values obtained are reported in Table 4 which reports, in the order: the number of the example (Example), the number that refers to the formula of the compound used (Compound formula), the number of the example wherein the compound has been prepared (Prep. example) and finally the luminescence quantum efficiency (Φ) expressed as a percentage (%).

TABLE-US-00004 TABLE 4 Compound Prep. Φ Example formula example (%) 13 (Ia) 1 95 14 (Ib) 2 85 15 (Ic) 3 80 16 (Id) 4 72

EXAMPLE 17 (COMPARATIVE)

[0121] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 49.5 mg of 4,7-di-(thien-2′-yl)-2,1,3-benzothiadiazole (DTB), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0122] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate. The main face of the polymer plate [the one coated with the thin film containing 4,7-di-(thien-2′-yl)-2,1,3-benzothiadiazole (DTB)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0123] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0124] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0125] It can be seen how, in the absence of edge effects, the average power generated is equal to 5.69 mW (FIG. 1).

[0126] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 18 (DISCLOSURE)

[0127] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 101.9 mg of 4,7-dithienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ia.sub.1) (DTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0128] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0129] 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 having formula (Ia.sub.1) (DTTBOP),] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0130] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0131] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0132] It can be seen how, in the absence of edge effects, the average power generated is equal to 2.90 mW (FIG. 1).

[0133] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 19 (DISCLOSURE)

[0134] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 72.3 mg of 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ib) (MPDTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0135] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0136] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ib) (MPDTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0137] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0138] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0139] It can be seen how, in the absence of edge effects, the average power generated is equal to 11.39 mW (FIG. 1).

[0140] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 20 (DISCLOSURE)

[0141] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 150.0 mg of 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ib) (MPDTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0142] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate. The main face of the polymer plate [the one coated with the thin film containing 4,7-di-(2,6-dimethylphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ib) (MPDTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0143] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0144] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0145] It can be seen how, in the absence of edge effects, the average power generated is equal to 13.30 mW (FIG. 1).

[0146] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 21 (DISCLOSURE)

[0147] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 47.8 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ic) (POPDTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0148] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0149] 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 having formula (Ic) (POPDTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0150] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0151] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0152] It can be seen how, in the absence of edge effects, the average power generated is equal to 8.84 mW (FIG. 1).

[0153] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 22 (DISCLOSURE)

[0154] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 86.1 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ic) (POPDTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0155] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0156] 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 having formula (Ic) (POPDTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0157] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0158] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0159] It can be seen how, in the absence of edge effects, the average power generated is equal to 9.25 mW (FIG. 1).

[0160] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 23 (DISCLOSURE)

[0161] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 172.2 mg of 4,7-di-2-(2-phenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Ic) (POPDTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0162] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0163] 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 having formula (Ic) (POPDTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0164] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0165] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0166] It can be seen how, in the absence of edge effects, the average power generated is equal to 6.84 mW (FIG. 1).

[0167] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 24 (DISCLOSURE)

[0168] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 241.0 mg of 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Id) (2,4,6-(POP) .sub.3DTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0169] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0170] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Id) (2,4,6-(POP).sub.3DTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0171] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0172] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0173] It can be seen how, in the absence of edge effects, the average power generated is equal to 11.25 mW (FIG. 1).

[0174] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa).

EXAMPLE 25 (DISCLOSURE)

[0175] 6 g of Altuglas VSUVT 100 (PMMA) polymethylmethacrylate and 158.0 mg of 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Id) (2,4,6-(POP) .sub.3DTTBOP), were dissolved in 30 ml of 1,2-dichlorobenzene (Aldrich). The obtained solution was subsequently deposited, evenly, on a polymethylmethacrylate plate (dimensions 300 mm×90 mm×6 mm) using a “Doctor Blade” type film applicator and the solvent was allowed to evaporate at room temperature (25° C.), in a light air flow, for 24 hours. The result was a transparent plate in yellow conferred by the film whose thickness was found to be comprised between 100 μm and 50 μm.

[0176] An IXYS-KXOB22-12 photovoltaic cell having a 1.2 cm.sup.2 surface was then applied to one of the edges of the polymer plate.

[0177] The main face of the polymer plate [the one coated with the thin film containing 4,7-di-2-(2,4,6-triphenoxyphenyl)thienothienyl-5,6-diphenoxy-2,1,3-benzothiadiazole having formula (Id) (2,4,6-(POP) .sub.3DTTBOP)] was then lit up with a light source with a power equal to 1 sun (1000 W/m.sup.2) and the electrical power generated by the effect of lighting was measured.

[0178] The power measurements (P) were made by illuminating a portion of a plate with dimensions equal to 100 mm×90 mm, at an increasing distance (d) from the edge on which the photovoltaic cell was fixed. These measurements at a variable distance from the photovoltaic cell allow the contribution of wave guide, edge, diffusion and self-absorption effects to be quantified.

[0179] FIG. 1 shows the curve relating to the generated power value (P) expressed in mW (reported on the ordinate), as a function of the distance (d) from the edge on which the photovoltaic cell was fixed, expressed in cm (reported on the abscissa).

[0180] It can be seen how, in the absence of edge effects, the average power generated is equal to 10.08 mW (FIG. 1).

[0181] FIG. 2 shows the power value (P) generated expressed in mW (reported on the ordinate) obtained (the number of the example is reported on the abscissa). substituted with thienothiophenic groups according to claim 1, wherein in said general formula (Ia): [0182] Z represents a sulphur atom; [0183] R.sub.1, equal to each other, represent a hydrogen atom; or are selected from optionally substituted aryl groups, preferably are 2,6-dimethylphenyl, 2-phenoxyphenyl, 2,4,6-triphenoxyphenyl; [0184] R.sub.2 and R.sub.3, equal to each other, represent a hydrogen atom; [0185] R.sub.4 is selected from optionally substituted aryl groups, preferably is phenyl.

[0186] 3. Luminescent solar concentrator (LSC) including at least one diaryloxylbenzoheterodiazole compound di-substituted with thienothiophenic groups having a general formula (Ia) according to claim 1 or 2.

[0187] 4. Photovoltaic device (or solar device) comprising at least one photovoltaic cell (or solar cell), and at least one luminescent solar concentrator (LSC) according to claim 3.

[0188] 5. Use of a photovoltaic device (or solar device) according to claim 4 in the construction of greenhouses.