Perovskite-based photovoltaic cells

Abstract

Photovoltaic cell (or solar cell) based on perovskite ("Perovskite Solar Cell" - PSC) comprising at least one layer comprising at least one amino alcohol having general formula (I): wherein: - R1 and R2, identical or different from each other, represent a hydrogen atom or a methyl group; or they are selected from C2-C4 alkyl groups, linear or branched, saturated, wherein one or more hydrogen atoms are optionally substituted with a hydroxyl group; preferably, a hydrogen atom; - R3 is selected from C2-C12 alkyl groups, preferably C2-C8, linear or branched, saturated or unsaturated, aryl groups, cycloalkyl groups, said alkyl, aryl and cycloalkyl groups being substituted with 1 to 5, preferably 1 to 3, hydroxyl groups and, optionally, with at least one group selected from alkyl groups, ether groups, ester groups, carbonyl groups. Said photovoltaic cell (or solar cell) based on perovskite ("Perovskite Solar Cell" - PSC) can be part of a tandem perovskite / silicon photovoltaic cell (or solar cell). Said photovoltaic cell (or solar cell) based on perovskite ("Perovskite Solar Cell" - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be advantageously used in various applications that require the production of electric energy by exploiting light energy, in particular the energy of solar radiation, such as, for example: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings. Said photovoltaic cell (or solar cell) based on perovskite ('Perovskite Solar Cell' - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be used either in stand-alone mode or in modular systems.

Description

[0001] PEROVSKITE-BASED PHOTOVOLTAIC CELLS

[0002] The present invention relates to photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs).

[0003] More particularly, the present invention relates to a photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) comprising at least one layer comprising at least one amino alcohol having the specific general formula (I) below reported.

[0004] Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) can be part of a tandem perovskite / silicon photovoltaic cell (or solar cell). Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be advantageously used in various applications that require the production of electric energy by exploiting light energy, in particular the energy of solar radiation, such as, for example: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings. Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be used either in stand-alone mode or in modular systems.

[0005] The present invention also relates to a tandem perovskite / silicon photovoltaic cell (or solar cell).

[0006] It is also a further object of the present invention a composition comprising at least one perovskite and at least one amino alcohol having the specific general formula (I) below reported.

[0007] Photovoltaic cells (or solar cells) are devices capable of converting the energy of a light radiation into electricity. At present, most photovoltaic cells (or solar cells) that can be used for practical applications exploit the chemical-physical properties of inorganic photoactive materials, particularly both crystalline and amorphous silicon, more particularly high-purity crystalline silicon.

[0008] Over the last decade, several new technologies related to photovoltaic cells (or solar cells) have attracted the attention of numerous research groups aroundthe world with the aim of improving the characteristics of photovoltaic cells (or solar cells) based on silicon such as, for example, access to new fields of application, improved efficiencies and possibly lower production costs.

[0009] In particular, photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) have rapidly become a promising alternative in recent years, as they combine a high energy conversion efficiency [“Power Conversion Efficiency” - (PCE)], which has currently reached a certified value of over 26%, a series of characteristics typical of thin-film organic photovoltaic cells (or solar cells) based on polymer (“Organic Photovoltaics” - OPVs) such as, for example, lightness, flexibility and the simplicity of the manufacturing process which, starting from appropriate mixtures of the various precursors, can enable the production of photovoltaic cells (or solar cells) by means of well-known and established printing processes (including continuous printing) under mild conditions and at a sustainable cost. Furthermore, in recent years it has been demonstrated that particular photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) can exploit solar radiation not absorbed by photovoltaic cells (or solar cells) based on silicon and thus appropriately coupled with said photovoltaic cells (or solar cells) based on silicon, they result in so-called tandem photovoltaic cells (or solar cells) whose efficiency to date is close to 35%, thus achieving a significant improvement over all commercially available technologies.

[0010] However, photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) may also have certain structural drawbacks which may also influence the macroscopic behaviour of said photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs), such as, for example, a relatively high density of defects (e.g., crystallinity defects, ion vacancies, etc.) both within the photoactive layer of perovskite (“bulk”) and at the edges of the crystalline grains, and on the surface of said photoactive layer of perovskite. Indeed, material interfaces represent an area of discontinuity in the photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC), and are the cause of the greatest gap between the theoretical performance of photovoltaiccells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) (without any loss due to corollary phenomena) and the actual performance due to the high electron-hole recombination rate at the interface. More precisely, said defects reduce the overall efficiency of the photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) and also facilitate the initiation of degradation phenomena.

[0011] To bridge the aforementioned gap, research is focusing on the use of agents capable of passivating defects commonly present both on the surface (by means of surface treatment) and within the photoactive layer of perovskite (by means of “bulk” treatment). In particular, as reported, for example, by M. M. Byranvand and M. Saliba, “Defect Passivation of Perovskite Films for Highly Efficient and Stable Solar Cells”, “Solar RRL" (2021), Vol. 5, 2100295; or by Abd. Rashid bin Mohd Yusoff et al, “Passivation and process engineering approaches of halide perovskite films for high efficiency and stability perovskite solar cells”, “Energy Environment Science" (2021), Vol. 14, p. 2906-2953, various compounds containing various functional groups capable of interacting via more or less strong bonds, with the perovskite surface have been used as passivating agents. Common passivating agents include, for example, certain fullerene derivatives, transition metal salts, alkaline earth metal salts and lanthanide salts, urea, propylene carbonate, hexafluoroisopropanol, nitrogen-doped reduced graphene oxide, tris(pentafluorophenyl)phosphine, trioctylphosphinoxide, tribenzylphosphinoxide, acetic acid, conjugated molecules with a 7t-acceptor donor-bridge structure, conjugated molecules with rhodanine groups, thiophene, pyridine, mercaptopyridine, benzylamine, lead sulphate, pentaerythritol tetrakis(3-mercaptopropionate), butanethiol, phenylethylammonium iodide, phenylethylammonium chloride, butylammonium iodide, octylammonium iodide, octyldiammonium iodide, benzyl ammonium iodide, 1,1,1-trifluoroethylammonium iodide 4-(aminomethyl)piperidinium iodide, 2-thiophenylmethylammonium iodide, 4-vinylbenzylammonium bromide, hexyltrimethylammonium bromide, azetidinium bromide, tetrakisammonium(zinc phthalocyanine) iodide, thiazoloammonium iodide,pentafluorophenyl ammonium iodide, 2-(4-fluorophenyl)ethylammonium iodide. Chinese patent application CN 111777522 relates to a passivating agent comprising an alkyl segment, the alkyl segment containing a functional group (A), a functional group (B) and at least one functional group (C), the functional group (A) being an amine group, the functional group (B) being a carboxyl group and the functional group (C) being at least one group selected from: an amine group, a thiol group, a hydroxyl group, an imidazole group, a lipid group, an amide group, a nitro group, an aldehydic group, an aromatic group, a cyano group and a sulphonate group. The aforementioned passivating agent is said to be able to act as an electron donor or acceptor compound, interact with the electronic structural defects of the perovskite layer, and have a good passivating effect both at the edges of the crystalline grains and on the surface of said perovskite layer.

[0012] Romanian patent application RO 138341 relates to a process for the preparation of photoactive layers of perovskite with added primary amino alcohols. Specifically, said process comprises the following steps: additivation of the hybrid perovskite MAPbI2.6Cl0.4(wherein MA is methylammonium) with a solution of 1,3-diamino-2-propanol (DAP) in

[0013]

[0014] -di methyl form am ide (DMF) at various concentrations (1 mg -5 mg DAP / ml DMF); deposition of a perovskite layer on an FTO / c-TiO2 / m-TiO2substrate by spin coating, at 2000 rpm, for 25 s, in a controlled atmosphere (N2), using chlorobenzene as an antisolvent. The aforementioned process is said to be able to provide stable photoactive perovskite layers with improved quality in terms of crystallinity and passivation of defects.

[0015] However, many of the compounds used as passivating agents may have critical aspects. For example, among those reported above, hexafluoroisopropanol, acetic acid, thiophene, pyridine, benzylamine, butanethiol, are compounds with a high vapour pressure and a relatively low boiling point (well below 200°C). Since during the manufacturing process of photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs), prolonged heat treatments are used at significant temperatures, which can reach, or in some cases even exceed, 150°C-180°C, said passivating agents can be removed to an uncontrollable extent, making the manufacturing process not very reproducible. Therefore, it would bepreferable to have non-volatile compounds or compounds with a boiling or sublimation temperature significantly higher than that to which photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSCs) are subjected during their manufacture. Furthermore, the use of ammonium iodides, which are very commonly used passivating agents, could be particularly inconvenient, as compounds of this type can be subject to undesirable decomposition reactions, especially when heated.

[0016] From what has been said above, it is clear that it is important to find other compounds that can be used as passivating agents both within the perovskite photoactive layer (by means of “bulk” treatment) and on its surface (by means of surface treatment), which allow to obtain photovoltaic cells (or solar cells) based on perovskite (“Perovskite Solar Cells” - PSC) that are capable of having a good power conversion efficiency [" Power Conversion Efficiency" - (PCE)].

[0017] The Applicant therefore set itself the problem of finding a photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) capable of having a good power conversion efficiency [" Power Conversion Efficiency" -(PCE)].

[0018] The Applicant has now found a photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) comprising at least one layer comprising at least one amino alcohol having the specific general formula (I) below reported, capable of having a good power conversion efficiency [" Power Conversion Efficiency" - (PCE)] (i.e. PCE > 16%). In addition, said photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) has low hysteresis index (“Hysteresis Index” -HI) values (i.e. values less than or equal to 1%). In addition, said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) is able to maintain good photovoltaic properties, i.e. good values of FF (" Fill Factor"), Voc (" Open Circuit Voltage"), Jsc ("short-circuit photocurrent density"). Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) can be part of a tandem perovskite / silicon photovoltaic cell (or solar cell). Said photovoltaic cell (or solar cell) based on perovskite ('Perovskite Solar Cell' - PSC) and said tandemperovskite / silicon photovoltaic cell (or solar cell) can be advantageously used in various applications that require the generation of electricity by exploiting light energy, in particular the energy of solar radiation, such as, for example: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings. Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be used either in stand-alone mode or in modular systems.

[0019] The present invention therefore relates to a photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) comprising at least one layer comprising at least one amino alcohol having general formula (I):

[0020] I1

[0021] N— R3(I)

[0022] R

[0023]

[0024] 2

[0025] wherein:

[0026] Ri and R2, identical or different from each other, represent a hydrogen atom or a methyl group; or they are selected from C2-C4 alkyl groups, linear or branched, saturated, wherein one or more hydrogen atoms are optionally substituted with a hydroxyl group; preferably, a hydrogen atom;

[0027] R3 is selected from C2-C12 alkyl groups, preferably C2-C8, linear or branched, saturated or unsaturated, aryl groups, cycloalkyl groups, said alkyl, aryl and cycloalkyl groups being substituted with 1 to 5, preferably 1 to 3, hydroxyl groups and, optionally, with at least one group selected from alkyl groups, ether groups, ester groups, carbonyl groups.

[0028] For the purpose of the present description and of the following claims, the definitions of the numeric ranges always include the extremes unless specified otherwise.

[0029] For the purpose of the present description and of the following claims, the term “comprising” also includes the terms “which essentially consists of’ or “which consists of’.

[0030] According to a preferred embodiment of the present invention, said at least one layer is the perovskite photoactive layer.In accordance with a further preferred embodiment of the present invention, said at least one layer is a layer positioned above and / or below the perovskite photoactive layer, preferably it is a layer positioned above the perovskite photoactive layer.

[0031] In accordance with a further preferred embodiment of the present invention, said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) comprises:

[0032] at least one layer positioned above and / or below the perovskite photoactive layer, preferably a layer positioned above the perovskite photoactive layer, comprising at least one amino alcohol having general formula (I); and a perovskite photoactive layer comprising at least one amino alcohol having general formula (I).

[0033] According to a preferred embodiment of the present invention, said perovskite may be selected, for example, from organometallic trihalides having general formula ABX3 wherein:

[0034] A represents a monovalent organic cation such as, for example, methylammonium (CH3NH3+), formamidinium [CH(NH2)2+],

[0035]

[0036] butylammonium (C4H9NH3+), tetra-butylammonium (C16H36N+), guanidinium [NH2(NH2)2+], or combinations thereof; or A represents a monovalent inorganic cation such as, for example, cesium (Cs+), rubidium (Rb+), potassium (K+), lithium (Li+), sodium (Na+), copper (Cu+), silver (Ag+), or combinations thereof; or combinations of at least one monovalent organic cation and at least one monovalent inorganic cation;

[0037] B represents a divalent metallic cation such as, for example, lead (Pb2+), tin (Sn2+), or combinations thereof;

[0038] X represents a halide anion such as, for example, iodide (I"), chloride (Cl’), bromide (Br‘), or combinations thereof.

[0039] In accordance with a further preferred embodiment of the present invention, said perovskite may be selected, for example, from: methylammonium lead iodide [CH3NH3PbI3], formamidinium lead iodide [CH(NH2)2PbI3], cesium lead iodide [CsPbI3], methylammonium formamidinium lead iodide[(CH3NH3)x(CH(NH2)2)1-xPbI3], cesium methylammonium lead iodide [Csx(CH3NH3)1-xPbI3], cesium formamidinium lead iodide [Csx(CH(NH2)2)1-xPbI3], cesium methylammonium formamidinium lead iodide [(CsxCH3NH3)y(CH(NH2)2)1-x-yPbI3], methylammonium lead bromide [CH3NH3PbBr3], formamidinium lead bromide [CH(NH2)2PbBr3], cesium lead bromide [CsPbBr3], methylammonium formamidinium lead bromide [(CH3NH3)x(CH(NH2)2)i-xPbBr3], cesium methylammonium lead bromide [Csx(CH3NH3)i-xPbBr3], cesium formamidinium lead bromide [Csx(CH(NH2)2)1-xPbBr3], cesium methylammonium formamidinium lead bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbBr3], methylammonium lead chloride [CH3NH3PbCl3], formamidinium lead chloride [CH(NH2)2PbCh], cesium lead chloride [CsPbCh], methylammonium formamidinium lead chloride [(CH3NH3)x(CH(NH2)2)i-xPbC13], cesium methylammonium lead chloride [Csx(CH3NH3)i-xPbC13], cesium formamidinium lead chloride [Csx(CH(NH2)2)1-xPbCl3], cesium methylammonium formamidinium lead chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbC13], methylammonium lead iodide bromide [CH3NH3Pbl3-wBrw], formamidinium lead iodide bromide [CH(NH2)2Pbl3-wBrw], cesium lead iodide bromide [CsPbl3-wBrw], methylammonium formamidinium lead iodide bromide [(CHsNHsJxfCHfNHz Ji-xPbh-wBrw],

[0040] cesium methylammonium lead iodide bromide [Csx(CH3NH3)i-xPbl3-wBrw], cesium formamidinium lead iodide bromide [Csx(CH(NH2)2)i-xPbl3-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-wBrw], methylammonium lead iodide chloride [CH3NH3Pbl3-wClw], formamidinium lead iodide chloride [CH(NH2)2Pbl3-wClw], cesium lead iodide chloride [CsPbl3-wClw], methylammonium formamidinium lead iodide chloride [(CH3NH3)x(CH(NH2)2)i-xPbl3-wClw], cesium methylammonium lead iodide chloride [Csx(CH3NH3)i-xPbl3-wClw], cesium formamidinium lead iodide chloride [Csx(CH(NH2)2)i-xPbl3-wClw], cesium methylammonium formamidinium lead iodide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-wClw], methylammonium lead bromide chloride [CH3NH3PbBr3-wClw], formamidinium lead bromide chloride[CH(NH2)2PbBr3-wClw], cesium lead bromide chloride [CsPbBr3-wClw], methylammonium formamidinium lead bromide chloride [(CH3NH3)x(CH(NH2)2)1-xPbBr3-wClw], cesium methylammonium lead bromide chloride [Csx(CH3NH3)i-xPbBr3-wClw], cesium formamidinium lead bromide chloride [Csx(CH(NH2)2)i-xPbBr3-wClw], cesium methylammonium formamidinium lead bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbBr3-wClw], methylammonium lead iodide bromide chloride [CH3NH3PbI3-w-vBrwClv], formamidinium lead iodide bromide chloride [CH(NH2)2Pbl3-w-vBrwClv], cesium lead iodide bromide chloride [CsPbl3-w-vBrwClv], methylammonium formamidinium lead iodide bromide chloride [(CH3NH3)x(CH(NH2)2)i-xPbl3-w-vBrwClv], cesium methylammonium lead iodide bromide chloride [Csx(CH3NH3)i-xPbl3-w-vBrwClv], cesium formamidinium lead iodide bromide chloride [Csx(CH(NH2)2)i-xPbl3-w-vBrwClv], cesium methylammonium formamidinium lead iodide bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-w-vBrwClv], methylammonium tin iodide [CH3NH3SnI3], formamidinium tin iodide [CH(NH2)2SnI3], cesium tin iodide [CsSnI3], methylammonium formamidinium tin iodide [(CH3NH3)x(CH(NH2)2)1-xSnI3], cesium methylammonium tin iodide [Csx(CH3NH3)i-xSnl3], cesium formamidinium tin iodide [Csx(CH(NH2)2)i-xSnl3], cesium methylammonium formamidinium tin iodide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3], methylammonium tin bromide [CH3NH3SnBr3], formamidinium tin bromide [CH(NH2)2SnBr3], cesium tin bromide [CsSnBr3], methylammonium formamidinium tin bromide [(CH3NH3)x(CH(NH2)2)1-xSnBr3], cesium methylammonium tin bromide [Csx(CH3NH3)i-xSnBr3], cesium tin formamidinium bromide [Csx(CH(NH2)2)i-xSnBr3], cesium methylammonium formamidinium tin bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnBr3], methylammonium tin chloride [CH3NH3SnCl3], formamidinium tin chloride [CH(NH2)2SnCh], cesium tin chloride [CsSnCh], methylammonium formamidinium tin chloride [(CH3NH3)x(CH(NH2)2)i-xSnC13], cesium methylammonium tin chloride [Csx(CH3NH3)i-xSnC13], cesium formamidinium tin chloride [Csx(CH(NH2)2)i-xSnC13], cesium methylammonium formamidinium tin chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnC13], methylammonium tin iodidebromide [CH3NH3SnI3-wBrw], formamidinium tin iodide bromide [CH(NH2)2SnI3-wBrw], cesium tin iodide bromide [CsSnl3-wBrw], methylammonium formamidinium tin iodide bromide [(CH3NH3)x(CH(NH2)2)1-xSnI3-wBrw], cesium methylammonium tin iodide bromide [Csx(CH3NH3)i-xSnl3-wBrw], cesium formamidinium tin iodide bromide [Csx(CH(NH2)2)1-xSnI3-wBrw], cesium methylammonium formamidinium tin iodide bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3-wBrw], methylammonium tin iodide chloride [CH3NH3Snl3-wClw], formamidinium tin iodide chloride [CH(NH2)2Snl3-wClw], cesium tin iodide chloride [CsSnl3-wClw], methylammonium formamidinium tin iodide chloride [(CH3NH3)x(CH(NH2)2)i-xSnl3-wClw], cesium methylammonium tin iodide chloride [Csx(CH3NH3)i-xSnl3-wClw], cesium formamidinium tin iodide chloride [Csx(CH(NH2)2)i-xSnl3-wClw], cesium methylammonium formamidinium tin iodide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3-wClw], methylammonium tin bromide chloride [CH3NH3SnBr3-wClw], formamidinium tin bromide chloride [CH(NH2)2SnBr3-wClw], cesium tin bromide chloride [CsSnBr3-wClw], methylammonium formamidinium tin bromide chloride [(CH3NH3)X(CH(NH2)2)I-xSnBr3-wClw], cesium methylammonium tin bromide chloride [Csx(CH3NH3)1-xSnBr3-wClw], cesium formamidinium tin bromide chloride [Csx(CH(NH2)2)1-xSnBr3-wClw], cesium methylammonium formamidinium tin bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnBr3-wClw], methylammonium tin iodide bromide chloride [CH3NH3SnI3-w-vBrwClv], formamidinium tin iodide bromide chloride [CH(NH2)2Snl3-w-vBrwClv], cesium tin iodide bromide chloride [CsSnI3-w-vBrwClv], methylammonium formamidinium tin iodide bromide chloride [(CH3NH3)x(CH(NH2)2)i-xSnl3-w-vBrwClv], cesium methylammonium tin iodide bromide chloride [Csx(CH3NH3)i-xSnl3-w-vBrwClv], cesium formamidinium tin iodide bromide chloride [Csx(CH(NH2)2)i-xSnl3-w-vBrwClv], cesium methylammonium formamidinium tin iodide bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3-w-vBrwClv], where in the case where only the index x is present, x is comprised between 0.01 and 0.99, in case where the indices x and y are present, the sum of x+y is comprised between 0.01 and 0.99 with x and y different from 0, in case where the only index w is present, w is comprisedbetween 0.01 and 2.99, in case the indices w and v are present, the sum of w+v is comprised between 0.01 and 2.99 with w and v different from 0. Preferably, said perovskite can be selected, for example, from: methylammonium lead iodide [CH₃NH₃PbI₃], formamidinium lead iodide [CH(NH₂)₂PbI₃], cesium lead iodide [CsPbI3], methylammonium formamidinium lead iodide [(CH3NH3)x(CH(NH2)2)1-xPbI3], cesium methylammonium lead iodide [Csx(CH3NH3)1-xPbI3], cesium formamidinium lead iodide [Csx(CH(NH2)2)1-xPbI3], cesium methylammonium formamidinium lead iodide [(CsxCH3NH3)y(CH(b>[H2)2)i-x-yPbl3], methylammonium lead iodide bromide [CH3NH3Pbl3-wBrw], formamidinium lead iodide bromide [CH(NH2)2Pbl3-wBrw], cesium lead iodide bromide [CsPbl3-wBrw], methylammonium formamidinium lead iodide bromide [(CH₃NH₃)x(CH(NH₂)₂)1-xPbI₃-wBrw], cesium methylammonium lead iodide bromide [Csx(CH₃NH₃)1-xPbI₃-wBrw], cesium formamidinium lead iodide bromide [Csx(CH(NH₂)₂)1-xPbI₃-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH₃NH₃)y(CH(NH₂)₂)1-x-yPbI₃-wBrw]; even more preferably between: cesium methylammonium lead iodide bromide [Csx(CH₃NH₃)1-xPbI₃-wBrw], cesium formamidinium lead iodide bromide [Csx(CH(NH₂)₂)1-xPbI₃-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH₃NH₃)y(CH(NH₂)₂)1-x-yPbI₃-wBrw].

[0041] In accordance with a further preferred embodiment of the present invention, said perovskite can be selected, for example, from perovskites having a “band gap” value comprised between 1.60 eV and 1.78 eV, preferably comprised between 1.65 eV and 1.72 eV.

[0042] Specific examples of C2-C4 alkyl groups, linear or branched, saturated, wherein one or more hydrogen atoms are optionally substituted with a hydroxyl group are: 2-hydroxyethyl, 2-hydroxypropyl, 3 -hydroxypropyl, 4-hydroxybutyl.

[0043] For the purpose of the present description and of the following claims, the term “C2-C12 alkyl groups substituted with 1 to 5 hydroxyl groups” indicates alkyl groups having from 1 to 12 carbon atoms, linear or branched, saturated or unsaturated, wherein one or more hydrogen atoms are substituted with a hydroxylgroup. Said C2-C12 alkyl groups substituted with 1 to 5 hydroxyl groups may be optionally substituted with one or more groups, identical or different from each other, selected from: alkyl groups; ether groups; ester groups; carbonyl groups. Specific examples of C2-C12 alkyl groups substituted with 1 to 5 hydroxyl groups are the following groups represented as radicals:

[0044] OH OH

[0045] * OH

[0046] OH 5

[0047] OH

[0048] OH

[0049]

[0050]

[0051] wherein the asterisk represents the nitrogen atom of the general formula (I).

[0052] For the purpose of the present description and of the following claims, the term " aryl groups substituted with 1 to 5 hydroxyl groups" indicates aryl groups having from 6 to 14 carbon atoms wherein one or more hydrogen atoms are substituted with a hydroxyl group. These aryl groups substituted with 1 to 5 hydroxyl groups may optionally be substituted with one or more groups, identical or different from each other, selected from: alkyl groups; ether groups; ester groups; carbonyl groups. Specific examples of aryl groups substituted with 1 to 5 hydroxyl groups are the following groups represented as radicals:

[0053] OH

[0054] OH

[0055] OH

[0056]

[0057] wherein the asterisk represents the nitrogen atom of the general formula (I). For the purpose of the present description and of the following claims, the term “cycloalkyl groups substituted with 1 to 5 hydroxyl groups” indicates cycloalkyl groups having from 3 to 10 carbon atoms wherein one or more hydrogen atoms are substituted with a hydroxyl group. These cycloalkyl groups substituted with 1 to 5 hydroxyl groups may optionally be substituted with one or more groups, identical or different from each other, selected from: alkyl groups; ether groups; ester groups; carbonyl groups. Specific examples of cycloalkyl groups substituted with 1 to 5 hydroxyl groups are the following groups represented as radicals:

[0058] OH

[0059]

[0060] wherein the asterisk represents the nitrogen atom of the general formula (I).

[0061] In accordance with a preferred embodiment of the present invention, said amino alcohol having general formula (I) can be selected, for example, from: 3- aminopropane-l,2-diol, 2-aminopropane- 1,3 -diol (serinol), 2-amino-2- hydroxymethylpropane- 1,3 -diol (tromethamine), 4-(2-aminoethyl)benzene- 1,2- diol (dopamine), 4-aminoresorcinol, or mixtures thereof. 2-Aminopropane-l,3- diol (serinol), 3 -aminopropane- 1,2-diol, 2-amino-2-hydroxymethylpropane-l,3- diol (tromethamine), are preferred.

[0062] For the purpose of the present invention, said amino alcohol having general formula (I) can be dissolved in an organic solvent.

[0063] Specific examples of organic solvents advantageously usable for the purpose of the present invention are: aromatic hydrocarbons such as, for example, toluene,benzene, o-xylene, p-xylene, m-xylene, or mixtures thereof; linear esters such as, for example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, butyl propionate, ethyl butyrate, propyl butyrate, butyl butyrate; cyclic esters such as, for example, y-butyrolactone, 5-valerolactone, or mixtures thereof; ethers such as, for example, diethyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethoxyethane, or mixtures thereof; amides such as, for example, N,N-dimethylformamide, N-methylpyrrolidone, dimethylacetamide, or mixtures thereof; sulfoxides such as, for example, dimethyl sulfoxide, diethyl sulfoxide, or mixtures thereof; nitriles such as, for example, acetonitrile, propionitrile, butyronitrile, benzonitrile, or mixtures thereof; alcohols such as, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, or mixtures thereof; ketones such as, for example, acetone, methyl ethyl ketone, cyclohexanone, or mixtures thereof; chlorinated solvents such as, for example, chloroform, methylene chloride, dichloroethane, tetrachloroethane, chlorobenzene, or mixtures thereof; or mixtures of said solvents.

[0064] It should be noted that:

[0065] in the case wherein the organic solvent is selected from among organic solvents defined as anti solvents of perovskite such as, for example, aromatic solvents, chlorinated solvents, linear esters, ethers, ketones, nitriles, alcohols, said solvents being selected from among those listed above, the aforementioned solution containing the amino alcohol having general formula (I) can be directly used for surface treatment of the perovskite photoactive layer (surface treatment) wherein a layer of the resulting solution is deposited above and / or below the perovskite photoactive layer, preferably above; or

[0066] in the case wherein the organic solvent used is selected from among organic solvents capable of dissolving perovskite such as, for example, sulfoxides, amides, cyclic esters, said solvents being selected from among those listed above, the aforementioned solution containing the amino alcohol having general formula (I) can be directly used in a mixture with the perovskiteprecursors with subsequent formation of the perovskite photoactive layer (“bulk” treatment).

[0067] More information relative the antisolvents used in photovoltaic cells (or solar cells) based on perovskite is reported, for example, by Ghosh S. et al. in " Advanced Materials Interfaces" (2020), Vol. 7, 200950, DOI: 10.1002 / admi.202000950.

[0068] In accordance with a preferred embodiment of the present invention, said at least one amino alcohol having general formula (I) can be present in the perovskite photoactive layer in an amount comprised between 0.01 millimoles and 5 millimoles, preferably comprised between 0.02 millimoles and 2 millimoles, with respect to the millimoles of lead.

[0069] In accordance with a preferred embodiment of the present invention, said at least one amino alcohol having general formula (I) can be present in the solution used in the surface treatment in order to obtain the layer positioned above and / or below the perovskite photoactive layer, in concentration comprised between 0.01 millimoles / litre and 100 millimoles / litre, preferably comprised between 0.1 millimoles / litre and 20 millimoles / litre.

[0070] In accordance with a preferred embodiment of the present invention, said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” -PSC) comprises:

[0071] a glass substrate covered with at least one layer of transparent and conductive oxide (" Transparent Conductive Oxide" - TCO), said oxide being preferably selected from fluorine doped tin oxide (SnO2:F) (" Fluorinedoped Tin Oxide" - FTO), indium tin oxide (" Indium Tin Oxide" - ITO), aluminium zinc oxide (AZO), indium zinc oxide (" Indium Zinc Oxide" IZO), hydrogenated indium oxide (" Hydrogenated Indium Oxide - IO: H), which constitutes the anode;

[0072] at least one layer based on a hole transport material (" Hole Transport Layer" - HTL), said material being preferably selected from (2-(3,6-dimethoxy-9H- carbazol-9-yl)ethyl phosphonic acid (MeO-2PACz)], 2-(9H-carbazol-9- yl)ethyl phosphonic acid (2PACz), nickel oxide (NiOx), coppersulfocyanide (CuSCN), copper iodide (Cui), copper oxide (CuOx), copper sulphide (CuS), or a combination of layers of the aforementioned materials; optionally at least one layer based on a material useful for improving wettability, preferably a layer of nanoparticles of aluminium oxide (n-AI2O3);

[0073] optionally, at least one layer containing at least one amino alcohol having general formula (I);

[0074] a photoactive layer comprising at least one perovskite preferably selected from cesium methylammonium lead iodide bromide [Cs₀.₀₅(CH₃NH₃)₀.₉₅PbI₂.₅₅Br₀.₄₅], cesium formamidinium lead iodide bromide [Cs₀.₁₇FA₀.₈₃PbI₂.₇₉Br₀.₃], more preferably cesium methylammonium lead iodide bromide [Cs₀.₀₅(CH₃NH₃)₀.₉₅PbI₂.₅₅Br₀.₄₅), and optionally, at least one amino alcohol having general formula (I), preferably 2-aminopropane-l,3-diol (serinol), 3 -aminopropane- 1,2-diol, 2-amino-2-hydroxymethylpropane- 1,3 -diol (tromethamine);

[0075] optionally, at least one layer comprising at least one amino alcohol having general formula (I);

[0076] at least one layer based on an electron transport material (" Electron Transport Layer" - ETL), said material being preferably selected from methyl ester of the [6,6]-phenyl-C6i-butyric acid (PC₆₁BM), fullerene (C60), tin oxide (SnOx), polyethyleneimine (PEI), ethoxylated polyethyleneimine (PEIE), or a combination of layers of the aforementioned materials; optionally, at least one layer based on a hole blocking material (" Hole Blocking Layer" - HBL), preferably 2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline (Batocuproine - BCP);

[0077] a cathode consisting of:

[0078] a metal contact known as "back contact" preferably a layer of gold, silver, or metallic aluminium; or,

[0079] a layer of transparent and conductive oxide (" Transparent Conductive Oxide" - TCO) and metal grids.

[0080] It should be noted, in fact, that in the case of tandem perovskite / siliconphotovoltaic cells (or solar cells) in the photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) the aforementioned metal contact known as “back contact” will be replaced by a layer of transparent and conductive oxide (“Transparent Conductive Oxide”-TCO) and metal grids forming the cathode.

[0081] In accordance with a preferred embodiment of the present invention, the electric energy generated by said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) may be transported using a "wiring system" which is connected with said photovoltaic cell (or solar cell) based on perovskite.

[0082] Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) can be prepared in accordance with processes known in the art.

[0083] For example, said photovoltaic cell (or solar cell) based on perovskite (“'Perovskite Solar Cell” - PSC) can be prepared by a process comprising the following stages:

[0084] (a) preparing a glass substrate covered with a layer of transparent and conductive oxide (TCO) (anode);

[0085] (b) depositing at least one layer based on hole transport material (" Hole Transport Layer" - HTL) on the substrate obtained in said stage (a);

[0086] (c) optionally, depositing on the layer based on a hole transport material (" Hole Transport Layer" - HTL) obtained in said stage (b) at least one layer based on a material for improving wettability;

[0087] (d) optionally depositing on the layer based on a hole transport material (“Hole Transport Layer” - HTL) obtained in said stage (b), or on the layer based on a material for improving wettability obtained in said stage (c), at least one layer comprising at least one amino alcohol having general formula (I); (e) preparing a mixture comprising perovskite precursors and, optionally, at least one amino alcohol having general formula (I);

[0088] (f) depositing, in the presence or absence of air, the mixture obtained in said stage (e) on the layer based on a hole transport layer (" Hole Transport Layer" - HTL) obtained in said stage (b), or on the layer based on a material forimproving wettability obtained in said stage (c), or on the layer comprising at least one amino alcohol having general formula (I) obtained in said stage (d), obtaining a photoactive layer;

[0089] (g) optionally, depositing on the photoactive layer obtained in said stage (f) at least one layer comprising at least one amino alcohol having general formula (I);

[0090] (h) depositing at least one layer based on an electron transport material (“Electron Transport Layer” - ETL), on the photoactive layer obtained in said stage (f) or on the layer comprising at least one amino alcohol having general formula (I) obtained in said stage (g);

[0091] (i) optionally, depositing on the layer based on an electron transport material (" Electron Transport Layer" - ETL) obtained in said stage (g), a layer based on a hole blocking material (" Hole Blocking Layer" - HBL);

[0092] (1) depositing a cathode comprising a metal contact known as a "back contact" preferably a gold, silver or aluminium metal layer, or, a cathode consisting of a transparent conductive oxide (" Transparent Conductive Oxide" - TCO) layer and metal grids, on the layer based on an electron transport layer (" Electron Transport Layer" - ETL) obtained in said stage (h), or on the layer based on a hole blocking material (" Hole Blocking Layer" - HBL) obtained in said stage (i).

[0093] It should be noted, in fact, that in the case of tandem perovskite / silicon photovoltaic cells (or solar cells) in said stage (1), on the layer based on an electron transport material (“Electron Transport Layer” - ETL) obtained in said stage (h) or on the layer based on a hole blocking material (“Hole Blocking Layer” - HBL) obtained in said step (i), a layer of transparent and conductive oxide (“Transparent Conductive Oxide” - TCO) and metal grids forming the cathode will be deposited.

[0094] For the purpose of the aforementioned process, said transparent conductive oxide (“Transparent Conductive Oxide” - TCO), said layer based on a hole transport material (“Hole Transport Layer” - HTL), said layer based on an electron transport material (“Electron Transport Layer” - ETL), said layer based on a material for improving wettability, said layer based on a hole blocking material(“Hole Blocking Layer” - HBL) and said metallic contact known as “back contact” are selected from those set forth above.

[0095] For the purpose of the aforementioned process, said mixture comprising perovskite precursors and optionally at least one amino alcohol having general formula (I), comprises:

[0096] at least one halide selected from among the halides of the monovalent organic cations or monovalent inorganic cations above reported, preferably iodides, chlorides, bromides, more preferably iodides and bromides, and at least one halide selected from among the halides of the bivalent metal cations above reported, preferably iodides, chlorides, bromides, more preferably iodides and bromides [for example, cesium iodide (CsI₂), lead iodide (PbI₂), lead bromide (PbBr₂)] as perovskite precursors; optionally at least one amino alcohol having general formula (I).

[0097] For the purpose of the aforementioned process, said stage (b), (c), (d), (e), (f), (g), (h) and (i) can be carried out according to depositing techniques known in the art such as, for example, “spray-coating”, “ink-jet printing”, “slot die coating”, “gravure printing”, “Physical Vapor Deposition” (PVD), “Radio Frequency Sputtering” (“RF-sputtering”), “Direct Current sputtering” (“DC-sputtering”), “Magnetron sputtering”, “Thermal evaporation”, “Electron Beam Evaporation” (EBE), “Chemical Vapor Deposition” (CVD), “Pulsed Laser Deposition (PLD), “Atomic Layer Deposition” (ALD): the technique used will vary depending on the layer considered.

[0098] For the purpose of the aforementioned process, said step (1) can be carried out according to techniques known in the art such as, for example, evaporation, cathodic sputtering, electron beam assisted depositing, “Physical Vapor Deposition” (PVD), “Radio Frequency Sputtering” (“RF-sputtering”), “Direct Current sputtering” (“DC-sputtering”).

[0099] As mentioned above, said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) can be part of a tandem perovskite / silicon photovoltaic cell (or solar cell).

[0100] Accordingly, it is a further object of the present invention a tandemperovskite / silicon photovoltaic cell (or solar cell) comprising:

[0101] a silicon photovoltaic cell (or solar cell);

[0102] a photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) comprising at least one layer comprising at least one amino alcohol having general formula (I), positioned above said silicon photovoltaic cell (or solar cell).

[0103] In accordance with a preferred embodiment of the present invention, the electric energy generated by said tandem perovskite / silicon photovoltaic cell (or solar cell) may be transported using a wiring system which is connected with said tandem perovskite / silicon photovoltaic cell (or solar cell).

[0104] As mentioned above, said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be advantageously used in various applications that require the generation of electricity by exploiting light energy, in particular the energy of solar radiation, such as, for example: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings. Said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) and said tandem perovskite / silicon photovoltaic cell (or solar cell) can be used either in stand-alone mode or in modular systems.

[0105] Accordingly, a further object of the present invention is the use of said photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” -PSC) or said tandem perovskite / silicon photovoltaic cell (or solar cell) in: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings.

[0106] As mentioned above, it is also a further object of the present invention a composition comprising at least one perovskite and at least one amino alcohol having general formula (I).

[0107] Accordingly, it is also a further object of the present invention a composition comprising at least one perovskite and at least one amino alcohol having general formula (I).

[0108] Said at least one perovskite can be selected from among those above reported.The present invention will now be illustrated in greater detail through an embodiment with reference to Figure 1 below reported.

[0109] In particular, Figure 1 depicts a cross-sectional view of a perovskite-based photovoltaic cell (or solar cell) (“Perovskite Solar Cell” - PSC) (1) comprising the following layers: a glass substrate (7) covered with a transparent conductive oxide (“TCO”) layer (anode) [e.g., indium tin oxide (“Indium Tin Oxide” - ITO)] (2); a layer based on a hole transport material (“Hole Transport Layer” - HTL) [e.g., (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl phosphonic acid (MeO-2PACz)] (3); optionally, a layer based on a material useful for improving wettability, (not shown in Figure 1); optionally, a layer comprising at least one amino alcohol having general formula (I) (not shown in Figure 1); a photoactive layer comprising at least one perovskite [e.g., cesium methylammonium lead iodide bromide (Cs0.05(CH3NH3)0.95PbI2.55Br0.45)) and optionally at least one amino alcohol having general formula (I), preferably 2-aminopropane-l,3-diol (serinol), 3-amino-propane-l,2-diol, 2-amino-2-hydroxymethylpropane- 1,3 -diol (tromethamine) (4); optionally a layer comprising at least one amino alcohol having general formula (I) (not shown in Figure 1); a layer based on an electron transport material [“Electron Transport Layer” (ETL)] (e.g., methyl ester of [6,6]-phenyl-C6i-butyric acid (PC₆₁BM)] (5a); a layer based on a hole blocking material (“Hole Blocking Layer” (HBL)) [e.g, 2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline (Batocuproine - BCP)] (5b); a metal contact known as a “back contact” that forms the cathode [e.g., a silver layer] (6).

[0110] In order to better understand the present invention and to put it into practice, some illustrative and non-limiting examples thereof are below reported.

[0111] In the following examples, for the sake of simplicity, the term "solar cell" is used, which is to be intended to have the same meaning as "photovoltaic cell".

[0112] EXAMPLE 1 (comparative)

[0113] Preparation of a perovskite-based solar cell (“Perovskite Solar Cell” - PSC)

[0114] For this purpose, a perovskite-based solar cell (“Perovskite Solar Cell” -PSC) was prepared on a glass substrate coated with ITO (“Indium Tin Oxide”) (Kintec KT18086-1) and patterned (dimensions 15x15x1 mm; “sheet resistance”equal to 12 Q / cm2) previously subjected to a cleaning process consisting of manual cleaning by wiping with a lint-free cloth soaked in a detergent diluted with deionized water. The substrate was then rinsed with deionized water. Subsequently, the substrate was thoroughly cleaned using the following methods in sequence: ultrasonic baths in (i) deionized water plus detergent (followed by manual drying with a lint-free cloth); (ii) distilled water [followed by manual drying with a lint-free cloth]; (iii) acetone (Merck) and (iv) iso-propanol (Merck) in sequence. In particular, the substrate was placed in a beaker containing the solvent, placed in an ultrasonic bath, kept at 40°C, for a treatment of 10 minutes. After treatments (iii) and (iv), the substrate was dried with a compressed nitrogen flow.

[0115] Subsequently, the glass / ITO was further cleaned by treatment in an ozone device (UV Ozone Cleaning System EXPO3 - Astel), immediately before proceeding to the next step.

[0116] The substrate thus treated was ready for the deposition of the layer based on a hole transport material (“Hole Transport Layer” - HTL). For this purpose, a solution of (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl phosphonic acid (MeO-2PACz) (Merck) in anhydrous ethanol (max. 0.003% by weight of water - VWR) at a concentration equal to 0.5 mg / ml was deposited by means of “spin-coating”, operating at a rotation speed equal to 3000 rpm (acceleration equal to 100 rpm / s), for 30 seconds: the whole was subjected to heat treatment (“annealing”), at 100°C, for 10 minutes. The layer based on a hole transport material (“Hole Transport Layer” - HTL) is a “self-assembly monolayer” with a thickness of < 1 nm.

[0117] On top of the layer based on a hole transport material (“Hole Transport Layer” - HTL) the cesium methylammonium lead iodide bromide layer [Cs0.05(CH3NH3)0.95PbI2.55Br0.45) was deposited (“band gap” of 1.67 eV) operating as follows. For this purpose, cesium iodide (CsI) (ultra dry purity 99.999% - Alfa Aesar) (15.6 mg - 0.06 mmoles), lead iodide (PbI2) (ultra dry purity 99.999% -Alfa Aesar) (428.7 mg - 0.93 mmoles), lead bromide (PbBr₂) (ultra dry purity 99.999% - Alfa Aesar) (99 mg - 0,27 mmoles) were dissolved in a mixture of anhydrous N,N-dimethylformamide (DMF) (purity 99.9% - Merck) (628.8 pl) andanhydrous dimethyl sulphoxide (DMS) (purity 99.8% - Merck) (157.2 pl), operating under stirring, at 130°C, for 5 minutes. Subsequently, after allowing the temperature to drop spontaneously to room temperature (25°C), methylammonium iodide (MAI) (CH3NH3I) - (Merck) (181,5 mg - 1.14 mmol) was added to the obtained solution and the whole was left, under stirring, at room temperature (25°C), for 10 minutes.

[0118] The solution thus obtained was deposited on top of the layer based on a hole transport material (“Hole Transport Layer” - HTL), by means of “spin coating” operating at a rotation speed equal to 4000 rpm (acceleration equal to 1000 rpm / s), for 30 seconds, with the addition of 300 pl of antisolvent (i. e. ethylacetate -Merck) after 8 seconds from the start of the operation, and the whole was subjected to heat treatment (“annealing”), at 100°C, for 30 minutes, operating in an uncontrolled atmosphere, in the presence of air. The thickness of the layer of perovskite was found to be equal to 330 nm.

[0119] The substrate thus obtained was ready for the deposition of the layer based on an electron transport material (“Electron Transport Layer” - ETL). For this purpose, a filtered solution of methyl ester of [6,6]-phenyl-C6i-butyric acid (PC₆₁BM) (Nano-C Products) (25 mg) in anhydrous chlorobenzene (purity 99.8% - Merck) (1 ml), was deposited, by means of “spin coating” operating at a rotation speed equal to 2000 rpm (acceleration equal to 500 rpm / s), for 60 seconds: the substrate obtained was allowed to rest, at room temperature (25°C), for 5 minutes. The thickness of the layer based on an electron transport material (“Electron Transport Layer” - HTL) was found to be equal to 50 nm.

[0120] The substrate thus obtained was ready for the deposition of the layer based on a hole blocking material (“Hole Blocking Layer” - HBL). For this purpose, a solution of 2,9-dimethyl-4,7-diphenyl-l,10-phenatroline (Batocuproine - BCP) (purity 96% - Merck) (9 mg) in anhydrous / .w-propyl alcohol (purity 99.5%-Merck) (18 ml) obtained by operating under stirring at 60°C, for 3 hours, was deposited, by spin coating operating at a rotation speed equal to 6000 rpm (acceleration equal to 1000 rpm / s), for 20 seconds, the substrate obtained was allowed to rest, at room temperature (25°C), for 5 minutes. The thickness of thelayer based on a hole blocking material (“Hole Blocking Layer” - HBL) was found to be equal to 5 nm.

[0121] Subsequently, silver (Ag) "back contact" (cathode) was deposited on said layer based on a hole blocking material (“Hole Blocking Layer” - HBL) by means of evaporation. For this purpose, a Kurt J. Lesker evaporator was used, operating at a pressure equal to 2xl0'6mmHg and a speed equal to 0.1 Angstrom / sec, suitably masking the area of the solar cell so as to obtain an active area equal to 4 mm2. The thickness of the silver (Ag) "back contact" (cathode) was found to be equal to 80 nm.

[0122] The thicknesses were measured by scanning electron microscopy using a Sigma-Zeiss Scanning Electron Microscope (SEM), equipped with a field emission electron gun, operating at an accelerating voltage equal to 5 kV, and exploiting the signal from secondary electrons.

[0123] The electrical characterization of the obtained perovskite-based solar cell was carried out at room temperature (25°C) operating as follows.

[0124] The current-voltage density (J-V) curves were acquired with a Keithley® 2400 digital multimeter connected to a personal computer for data collection. The photocurrent was measured by exposing the solar cell to the light of a Sinus-270 solar simulator (Class AAA - Wavelabs) placed at a distance of 10 mm from said solar cell, providing a solar spectrum classified as AM 1.5G and having an irradiance equivalent to 1 sun (100 mW / cm2), using an illumination spot of 100 mm x 100 mm. The AM 1.5G spectrum was calibrated using a certified silicon cell (Open RR-1002, KG5 window). Current-voltage characteristic curves were acquired in both the “reverse scan” direction i.e. from Voc“Open Circuit Voltage” to Jsc“short-circuit photocurrent density” and the “forward scan” direction i.e. from Jsc “short-circuit photocurrent density” to Voc“Open Circuit Voltage”, keeping the other acquisition parameters fixed. Table 1 shows the average and maximum “Power Conversion Efficiency” (PCE) and the “Hysteresis Index” (HI) calculated as the difference between the “Power Conversion Efficiency” (PCE) in the “reverse scan” direction and the “Power Conversion Efficiency” (PCE) in the “forward scan” direction, divided by the “Power Conversion Efficiency” (PCE) inthe “reverse scan direction”, all multiplied by 100, according to the following formula:

[0125] HY (%) = |((PCEreverse scan- PCEforward scan) / PCEreverse scan) × 100|

[0126]

[0127] PCEreverse scanThe result obtained is shown in Table 1 as an absolute value. Table 1 also shows the values of FF (“Fill Factor”), Voc (“Open Circuit Voltage”) and Jsc (“short-circuit photocurrent density”).

[0128] EXAMPLE 2 (invention)

[0129] Preparation of a solar cell based on perovskite (surface treatment)

[0130] A solar cell based on perovskite was prepared by operating as described in Example 1, with the only difference being the surface treatment of the perovskite photoactive layer.

[0131] For this purpose, 4.6 mg serinol (Merck) (0.05 mmol) was dissolved in 100 ml of iso-propanol (Merck) and the solution thus obtained was heated at 45°C, for 30 minutes, under stirring. Subsequently, 40 pl of the solution thus obtained was deposited on said perovskite photoactive layer by means of spin coating operating at a rotational speed of 5000 r.p.m. (acceleration equal to 2000 rpm / s), for 30 seconds, and the whole was subjected to heat treatment (“annealing”), at 100°C, for 30 minutes, operating in an uncontrolled atmosphere, in the presence of air. The thickness of the active layer was found to be equal to 330 nm.

[0132] The electrical characterisation of the solar cell based on perovskite thus obtained was carried out as described above: Table 1 shows the results obtained.

[0133] EXAMPLE 3 (invention)

[0134] Preparation of a solar cell based on perovskite (surface treatment)

[0135] A solar cell based on perovskite was prepared by operating as described in Example 1, with the only difference being the surface treatment of the perovskite photoactive layer.

[0136] For this purpose, 9.2 mg serinol (Merck) (0.1 mmol) was dissolved in 100 ml of iso-propanol (Merck) and the solution thus obtained was heated at 45°C, for 30 minutes, under stirring. Subsequently, 40 pl of the solution thus obtained was deposited on said perovskite photoactive layer by means of spin coating operating at a rotational speed of 5000 r.p.m. (acceleration equal to 2000 rpm / s), for 30seconds, and the whole was subjected to heat treatment (“annealing”), at 100°C, for 30 minutes, operating in an uncontrolled atmosphere, in the presence of air. The thickness of the active layer was found to be equal to 330 nm.

[0137] The electrical characterisation of the solar cell based on perovskite thus obtained was carried out as described above: Table 1 shows the results obtained.

[0138] EXAMPLE 4 (invention)

[0139] Preparation of a perovskite-based solar cell (“bulk” treatment)

[0140] A perovskite-based solar cell was prepared by operating as described in Example 1, with the only difference being the “bulk” treatment of the perovskite photoactive layer.

[0141] To this end, 4.6 mg of serinol (Merck) (0.05 mmol) [0.042 millimoles of amino alcohol having general formula (I) relative to millimoles of lead] was added to the solution of perovskite precursors obtained as shown in Example 1 above, and the resulting solution was heated to 45°C, for 30 minutes, under stirring. Subsequently, 20 pl of the solution thus obtained was deposited above the layer based on a hole transport material (“Hole Transport Layer” - HTL), by means of “spin coating” operating at a rotation speed equal to 4000 rpm (acceleration equal to 1000 rpm / s), for 30 seconds, with the addition of 300 pl of antisolvent (i.e. ethylacetate - Merck) after 8 seconds from the start of the operation, and the whole was subjected to heat treatment (“annealing”), at 100°C, for 30 minutes, operating in an uncontrolled atmosphere, in the presence of air. The thickness of the layer of perovskite was found to be equal to 330 nm.

[0142] The electrical characterisation of the perovskite-based solar cell obtained was carried out as described above: Table 1 shows the results obtained.

[0143] EXAMPLE 5 (invention)

[0144] Preparation of a perovskite-based solar cell (“bulk” treatment)

[0145] A perovskite-based solar cell was prepared by operating as described in Example 1, with the only difference being the “bulk” treatment of the perovskite photoactive layer.

[0146] To this end, 9.2 mg of serinol (Merck) (0.1 mmol) [0.083 millimoles of amino alcohol having general formula (I) relative to millimoles of lead] was addedto the solution of perovskite precursors obtained as shown in Example 1 above, and the resulting solution was heated to 45 °C, for 30 minutes, under stirring. Subsequently, 20 pl of the solution thus obtained was deposited on top of the layer based on a hole transport material (“Hole Transport Layer” - HTL), by means of “spin coating” operating at a rotation speed equal to 4000 rpm (acceleration equal to 1000 rpm / s), for 30 seconds, with the addition of 300 pl of antisolvent (i.e. ethylacetate - Merck) after 8 seconds from the start of the operation, and the whole was subjected to heat treatment (“annealing”), at 100°C, for 30 minutes, operating in an uncontrolled atmosphere, in the presence of air. The thickness of the layer of perovskite was found to be equal to 330 nm.

[0147] The electrical characterisation of the perovskite-based solar cell obtained was carried out as described above: Table 1 shows the results obtained.

[0148] Table 1

[0149] Example PCE(1)PCE(1)HI'21FF(3)Voc(4)Jsc(5)average maximum (%)

[0150] (%) (V) (mA / cm2) 1 13.87 14.97 2.00 69.5 1.104 18.1 (comparative)

[0151] 2 18.81 21.12 0.74 79.7 1.167 20.1 (invention)

[0152] 3 19.24 20.86 0.35 80.4 1.165 20.5 (invention)

[0153] 4 16.57 18.18 0.78 76.7 1.155 19.2 (invention)

[0154] 5 18.73 19.43 0.66 80.0 1.173 19.4

[0155]

[0156] (invention)

[0157] Power Conversion Efficiency;

[0158] (2): Hysteresis Index;

[0159] (3): Fill Factor;

[0160] (4): Open Circuit Voltage;

[0161] (5): short-circuit photocurrent density.

[0162] From the data shown in Table 1, it can be seen that the perovskite-based solar cells of the present invention (Examples 2-5) have both good power conversion efficiency (PCE) (i.e. PCE > 16%) [higher than that of the comparison solar cells (Example 1)], and low hysteresis values (i.e. values lower than 1%) [lower than those of the comparison solar cells (Example 1)], and good electrical properties, i.e. good values of FF (“Fill Factor”), Voc (“Open Circuit Voltage”);Jsc (“short-circuit photocurrent density”).

Claims

CLAIMS1. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) comprising at least one layer comprising at least one amino alcohol having general formula (I):I1N— R3(I)R2wherein:Ri and R2, identical or different from each other, represent a hydrogen atom or a methyl group; or they are selected from C2-C4 alkyl groups, linear or branched, saturated, wherein one or more hydrogen atoms are optionally substituted with a hydroxyl group; preferably, a hydrogen atom; R3 is selected from C2-C12 alkyl groups, preferably C2-C8, linear or branched, saturated or unsaturated, aryl groups, cycloalkyl groups, said alkyl, aryl and cycloalkyl groups being substituted with 1 to 5, preferably 1 to 3, hydroxyl groups and, optionally, with at least one group selected from alkyl groups, ether groups, ester groups, carbonyl groups.

2. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to claim 1, wherein said at least one layer is the perovskite photoactive layer.

3. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell " - PSC) according to claim 1, wherein said at least one layer is a layer positioned above and / or below the perovskite photoactive layer, preferably it is a layer positioned above the perovskite photoactive layer.

4. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to claim 1, comprising:at least one layer positioned above and / or below the perovskite photoactive layer, preferably a layer positioned above the perovskite photoactive layer, comprising at least one amino alcohol having general formula (I); and a perovskite photoactive layer comprising at least one amino alcohol having general formula (I).

5. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein said perovskite is selected from organometallic trihalides having general formula ABX3wherein:A represents a monovalent organic cation such as methylammonium (CH3NH3+), formamidinium [CH(NH2)2+], / / -butylammonium (C4H9NH3+), tetra-butylammonium (C16H36N+), guanidinium [NH2(NH2)2+], or combinations thereof; or A represents a monovalent inorganic cation such as cesium (Cs+), rubidium (Rb+), potassium (K+), lithium (Li+), sodium (Na+), copper (Cu+), silver (Ag+), or combinations thereof; or combinations of at least one monovalent organic cation and at least one monovalent inorganic cation;B represents a divalent metallic cation such as lead (Pb2+), tin (Sn2+), or combinations thereof;X represents a halide anion such as iodide (P), chloride (CP), bromide (Br‘), or combinations thereof.

6. Photovoltaic cell (or solar cell) based on perovskite (“Perovskite Solar Cell” - PSC) according to any one of the preceding claims, wherein said perovskite is selected from: methylammonium lead iodide [CH3NH3PbI3], formamidinium lead iodide [CH(NH2)2PbI3], cesium lead iodide [CsPbI3], methylammonium formamidinium lead iodide [(CH3NH3)x(CH(NH2)2)i-xPbI3], cesium methylammonium lead iodide [Csx(CH3NH3)i-xPbI3], cesium formamidinium lead iodide [Csx(CH(NH2)2)i-xPbI3], cesium methylammonium formamidinium lead iodide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbI3], methylammonium lead bromide [CH3NH3PbBr3], formamidinium lead bromide [CH(NH2)2PbBr3], cesium lead bromide [CsPbBr3], methylammonium formamidinium lead bromide [(CH3NH3)x(CH(NH2)2 i-\PbBr3], cesium methylammonium lead bromide [Csx(CH3NH3)i.xPbBr3], cesium formamidinium lead bromide [CSX(CH(NH2)2)I-xPbBr3], cesium methylammonium formamidinium lead bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbBr3], methylammonium lead chloride [CH3NH3PbCl3], formamidinium lead chloride [CH(NH2)2PbCl3], cesium lead chloride [CsPbCl3], methylammonium formamidinium lead chloride [(CH3NH3)X(CH(NH2)2)i-xPbCh], cesium methylammonium lead chloride [CSX(CH3NH3)I-xPbCh], cesium formamidinium lead chloride [Csx(CH(NH2)2)i-xPbC13], cesium methylammonium formamidinium lead chloride [(CsxCHsNHslvfCHfNI-b Ji-x-yPbCh], methylammonium lead iodide bromide [CftNHaPbh-wBrw], formamidinium lead iodide bromide [CH(NH2)2Pbl3-wBrw], cesium lead iodide bromide [CsPbl3-wBrw], methylammonium formamidinium lead chloride bromide [(CH3NH3)x(CH(NH2)2)i-xPbl3-wBrw],cesium methylammonium lead iodide bromide [Csx(CH3NH3)i-xPbl3-wBrw], cesium formamidinium lead iodide bromide [Csx(CH(NH2)2)i-xPbl3-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-wBrw], methylammonium lead iodide chloride [CH3NH3Pbl3-wClw], formamidinium lead iodide chloride [CH(NH2)2Pbl3-wClw], cesium lead iodide chloride [CsPbl3-wClw], methylammonium formamidinium lead iodide chloride [(CH3NH3)x(CH(NH2)2)i-xPbl3-wClw], cesium methylammonium lead iodide chloride [Csx(CH3NH3)i-xPbl3-wClw], cesium formamidinium lead iodide chloride [Csx(CH(NH2)2)i-xPbl3-wClw], cesium methylammonium formamidinium lead iodide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-wClw], methylammonium lead bromide chloride [CH3NH3PbBr3-wClw], formamidinium lead bromide chloride [CH(NH2)2PbBr3-wClw], cesium lead bromide chloride [CsPbBr3-wClw], methylammonium formamidinium lead bromide chloride [(CHaNHa (CH(NH2)2)i-xPbBr3-wClw], cesium methylammonium lead bromide chloride [Csx(CH3NH3)i-xPbBr3-wClw], cesium formamidinium lead bromide chloride [Csx(CH(NH2)2)i-xPbBr3.wClw], cesium methylammonium formamidinium lead bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbBr3-wClw], methylammonium lead iodide bromide chloride [CH3NH3PbI3-w-vBrwClv], formamidinium lead iodide bromide chloride [CH(NH2)2Pbl3-w-vBrwClv], cesium lead iodide bromide chloride [CsPbl3-w-vBrwClv], methylammonium formamidinium lead iodide bromide chloride [(CH3NH3)x(CH(NH2)2)i-xPbl3-w-vBrwClv], cesium methylammonium lead iodide bromide chloride [Csx(CH3NH3)i-xPbl3-w-vBrwClv], cesium formamidinium lead iodide bromide chloride [Csx(CH(NH2)2)i-xPbl3-w-vBrwClv], cesium methylammonium formamidinium lead iodide bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-w-vBrwClv], methylammonium tin iodide [CH3NH3SnI3], formamidinium tin iodide [CH(NH2)2SnI3], cesium tin iodide [CsSnI3], methylammonium formamidinium tin iodide [(CH3NH3)X(CH(NH2)2)I-xSnt], cesium methylammonium tin iodide [Csx(CH3NH3)i-xSnl3], cesium formamidinium tin iodide [Csx(CH(NH2)2)i-xSnl3], cesium methylammonium formamidinium tin iodide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3], methylammonium tin bromide [CH3NH3SnBr3], formamidinium tin bromide [CH(NH2)2SnBr3], cesium tin bromide [CsSnBr3], methylammonium formamidinium tin bromide [(CH3NH3)x(CH(NH2)2)1-xSnBr3], cesium methylammonium tin bromide [Csx(CH3NH3)i-xSnBr3], cesium formamidinium tin bromide [Csx(CH(NH2)2)i-xSnBr3], cesium methylammonium formamidinium tin bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnBr3], methylammonium tin chloride [CJbNEhSnCh], formamidinium tin chloride [CH(NH2)2SnCh], cesium tin chloride [CsSnCh], methylammonium formamidinium tin chloride [(CH3NH3)x(CH(NH2)2)i-xSnC13], cesium methylammonium tin chloride [Csx(CH3NH3)i-xSnC13], cesium formamidinium tin chloride [CSX(CH(NH2)2)I-xSnCh], cesium methylammonium formamidinium tin chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnC13], methylammonium tin iodide bromide [CH3NH3Snl3-wBrw], formamidinium tin iodide bromide [CH(NH2)2Snl3-wBrw], cesium tin iodide bromide [CsSnl3-wBrw], methylammonium formamidinium tin iodide bromide [(CHaNHa (CH(NH2)2)i-xSnl3-wBrw], cesium methylammonium tin iodide bromide [Csx(CH3NH3)i-xSnl3-wBrw], cesium formamidinium tin iodide bromide [Csx(CH(NH2)2)1-xSnI3-wBrw], cesium methylammonium formamidinium tin iodide bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3-wBrw], methylammonium tin iodide chloride [CftNHaSnh-wClw], formamidinium tin iodide chloride [CH(NH2)2Snl3-wClw], cesium tin iodide chloride [CsSnl3-wClw], methylammonium formamidinium tin iodide chloride [(CH3NH3)X(CH(NH2)2)I-xSnh-wClw], cesium methylammonium tin iodide chloride [Csx(CH3NH3)i-xSnl3-wClw], cesium formamidinium tin iodide chloride [Csx(CH(NH2)2)i-xSnl3-wClw], cesium methylammonium formamidinium tin iodide chloride[(CsxCH3NH3)y(CH(NH2)2)i-x-ySnl3.wClw], methylammonium tin bromide chloride [CH3NH3SnBr3.wClw], formamidinium tin bromide chloride [CH(NH2)2SnBr3.wClw], cesium tin bromide chloride [CsSnBr3.wClw], methylammonium formamidinium tin bromide chloride [(CH3NH3)X(CH(NH2)2)I-xSnBr3.wClw], cesium methylammonium tin bromide chloride [CSX(CH3NH3)I-xSnBr3.wClw], cesium formamidinium tin bromide chloride [CSX(CH(NH2)2)I-xSnBr3.wClw], cesium methylammonium formamidinium tin bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnBr3.wClw], methylammonium tin iodide bromide chloride [CH3NH3SnI3.w-vBrwClv], formamidinium tin iodide bromide chloride [CH(NH2)2SnI3.w-vBrwClv], cesium tin iodide bromide chloride [CsSnI3.w-vBrwClv], methylammonium formamidinium tin iodide bromide chloride [(CH3NH3)x(CH(NH2)2)i-xSnI3.w-vBrwClv], cesium methylammonium tin iodide bromide chloride [Csx(CH3NH3)|. SnI3.w.vBrwClv], cesium formamidinium tin iodide bromide chloride [Csx(CH(NH2)2)i-\SnI3.w.vBrwClv], cesium methylammonium formamidinium tin iodide bromide chloride [(CsxCH3NH3)y(CH(NH2)2)i-x-ySnI3.w-vBrwClv], wherein in the case where only the index x is present, x is comprised between 0.01 and 0.99, in case where the indices x and y are present, the sum of x+y is comprised between 0.01 and 0.99 with x and y different from 0, in case where the only index w is present, w is comprised between 0.01 and 2.99, in case the indices w and v are present, the sum of w+v is comprised between 0.01 and 2.99 with w and v different from 0; preferably, from among: methylammonium lead iodide [CH3NH3PbI3], formamidinium lead iodide [CH(NH2)2PbI3], cesium lead iodide [CsPbI3], methylammonium formamidinium lead iodide [(CH3NH3)x(CH(NH2)2)i-xPbI3], cesium methylammonium lead iodide [Csx(CH3NH3)i-xPbI3], cesium formamidinium lead iodide [CSX(CH(NH2)2)I-xPbI3], cesium methylammonium formamidinium lead iodide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbI3], methylammonium lead iodide bromide [CH3NH3PbI3.wBrw], formamidinium lead iodide bromide [CH(NH2)2PbI3.wBrw], cesium lead iodide bromide [CsPbI3.wBrw], methylammonium formamidinium lead iodide bromide [(CH3NH3)X(CH(NH2)2)i-xPbI3.wBrw], cesium methylammonium lead iodide bromide [Csx(CH3NH3)i-xPbI3.wBrw], cesiumformamidinium lead iodide bromide [Csx(CH(NH2)2)i-xPbl3-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH3NH3)y(CH(NH2)2)i-x-yPbl3-wBrw]; even more preferably from: cesium methylammonium lead iodide bromide [Csx(CH₃NH₃)1-xPbI₃-wBrw], cesium formamidinium lead iodide bromide [Csx(CH(NH₂)₂)1-xPbI₃-wBrw], cesium methylammonium formamidinium lead iodide bromide [(CsxCH₃NH₃)y(CH(NH₂)₂)1-x-yPbI₃-wBrw].

7. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein said perovskite is selected from perovskites having a "band gap" value comprised between 1.60 eV and 1.78 eV, preferably comprised between 1.65 eV and 1.72 eV.

8. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein said amino alcohol having general formula (I) is selected from: 3 -aminopropan- 1,2-diol, 2-aminopropan-l,3-diol (serinol), 2-amino-2-hydroxymethylpropan-l,3-diol (tromethamine), 4-(2-aminoethyl)benzene- 1,2-diol (dopamine), 4-aminoresorcinol, or mixtures thereof; preferably between 2-aminopropane-l,3-diol (serinol), 3 -aminopropane- 1,2-diol, 2-amino-2-hydroxymethylpropane-l,3-diol (tromethamine).

9. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein said at least one amino alcohol having general formula (I) is present in the perovskite photoactive layer in an amount comprised between 0.01 millimoles and 5 millimoles, preferably comprised between 0.02 millimoles and 2 millimoles, with respect to the millimoles of lead.

10. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein said at least one amino alcohol having general formula (I) is present in the solution used in the surface treatment in order to obtain the layer positioned above and / or below the perovskite photoactive layer, in concentration comprised between 0.01 millimoles / litre and 100 millimoles / litre, preferably comprised between 0.1millimoles / litre and 20 millimoles / litre.

11. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, comprising:a glass substrate covered with at least one layer of transparent and conductive oxide (" Transparent Conductive Oxide" - TCO), said oxide being preferably selected from fluorine doped tin oxide (SnO2:F) (FTO), indium tin oxide (ITO), aluminium zinc oxide (AZO), indium zinc oxide (IZO), hydrogenated indium oxide (IO: H), which constitutes the anode; at least one layer based on a hole transport material (" Hole Transport Layer" - HTL), said material being preferably selected from (2- (3,6-dimethoxy- 9H-carbazol-9-yl)ethyl phosphonic acid (MeO-2PACz)], 2-(9H-carbazol-9- yl)ethyl phosphonic acid (2PACz), nickel oxide (NiOx), copper sulfocyanide (CuSCN), copper iodide (Cui), copper oxide (CuOx), copper sulphide (CuS), or a combination of layers of the aforementioned materials; optionally at least one layer based on a material useful for improving wettability, preferably a layer of nanoparticles of aluminium oxide (n-Al2O3);optionally, at least one layer containing at least one amino alcohol having general formula (I);a photoactive layer comprising at least one perovskite preferably selected from cesium methylammonium lead iodide bromide [Cs₀.₀₅(CH₃NH₃)₀.₉₅PbI₂.₅₅Br₀.₄₅], cesium formamidinium lead iodide bromide [Cs₀.₁₇FA₀.₈₃PbI₂.₇₉Br₀.₃], more preferably cesium methylammonium lead iodide bromide [Cs₀.₀₅(CH₃NH₃)₀.₉₅PbI₂.₅₅Br₀.₄₅), and optionally, at least one amino alcohol having general formula (I), preferably 2-aminopropane-l,3-diol (serinol), 3 -aminopropane- 1,2-diol, 2- amino-2-hydroxymethylpropane- 1,3 -diol (tromethamine);optionally, at least one layer comprising at least one amino alcohol having general formula (I);at least one layer based on an electron transport material (" Electron Transport Layer" - ETL), said material being preferably selected frommethyl ester of the [6,6]-phenyl-C6i-butyric acid (PC₆₁BM), fullerene (C60), tin oxide (SnOx), polyethyleneimine (PEI), ethoxylated polyethyleneimine (PEIE), or a combination of layers of the aforementioned materials; optionally, at least one layer based on a hole blocking material (" Hole Blocking Layer" - HBL), preferably 2,9-dimethyl-4,7-diphenyl-l,10- phenanthroline (Batocuproine - BCP);a cathode consisting of:a metal contact known as "back contact" preferably a layer of gold, silver, or metallic aluminium; or,a layer of transparent and conductive oxide (" Transparent Conductive Oxide" - TCO) and metal grids.

12. Photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of the preceding claims, wherein the electric energy generated by said photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) is transported using a wiring system which is connected with said perovskite-based photovoltaic cell (or solar cell).

13. Tandem perovskite / silicon photovoltaic cell (or solar cell) comprising: a silicon photovoltaic cell (or solar cell);a photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) comprising at least one layer comprising at least one amino alcohol having general formula (I) according to any one of the preceding claims, disposed above said silicon photovoltaic cell (or solar cell).

14. Tandem perovskite / silicon photovoltaic cell (or solar cell) according to claim 12, wherein the electric energy generated by said tandem perovskite / silicon photovoltaic cell (or solar cell) is transported using a wiring system which is connected with said tandem perovskite / silicon photovoltaic cell (or solar cell).

15. Use of a photovoltaic cell (or solar cell) based on perovskite (" Perovskite Solar Cell" - PSC) according to any one of claims 1 to 11, or of a tandem perovskite / silicon photovoltaic cell (or solar cell) according to claim 13 or 14 in: photovoltaic fields (or photovoltaic parks), residential use, commercial buildings.

16. Composition comprising at least one perovskite according to any one ofclaims 5 to 7, and at least one amino alcohol having general formula (I) according to claim 1.

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