Abstract: A tandem solar cell comprises a front subcell; a back subcell; and an interconnecting layer of Cr/MoO3 between the front subcell and the back subcell and connecting the two subcells in series. The back subcell may be an isoindigo-based polymer. The front subcell may comprise a carbazole-thienyl-benzothiadiazole based polymer. The front subcell may comprise an isoindigo-based polymer. The isoindigo-based polymer is a repeating 2-thiophene-terminated polymer. A tandem solar cell comprises a substrate layer; a layer of PCDTBT:PC71BM applied on the substrate layer; a bilayer of chromium and MoO3 applied to the PCDTBT:PC71BM layer; a layer of P(T3-il)-2:PC71BM applied on the bilayer of chromium and MoO3; and Ca and Al electrode layer on the top.

Abstract: A tandem solar cell comprises a back subcell; a front subcell; and an interconnecting layer of Cr/MoO3 between the back subcell and the front subcell and connecting the two subcells in series. The front subcell may comprise a carbazole-thienyl-benzothiadiazole based polymer and the back subcell may comprise an isoindigo-based polymer. A method for making a tandem solar cell comprises a) providing a substrate layer; b) applying a layer of PCDTBT:PC71BM to the substrate layer; c) applying a bilayer of chromium and MoO3 to the PCDTBT:PC71BM layer; d) applying a layer of P(T3-iI)-2:PC71BM on the bilayer of chromium and MoO3; and e) applying a Ca and Al electrode layer on the top.

Abstract: A tandem solar cell comprises a front subcell; a back subcell; and an interconnecting layer of Cr/MoO3 between the front subcell and the back subcell and connecting the two subcells in series. The back subcell may be an isoindigo-based polymer. The front subcell may comprise a carbazole-thienyl-benzothiadiazole based polymer. The front subcell may comprise an isoindigo-based polymer. The isoindigo-based polymer is a repeating 2-thiophene-terminated polymer. A tandem solar cell comprises a substrate layer; a layer of PCDTBT:PC71BM applied on the substrate layer; a bilayer of chromium and MoO3 applied to the PCDTBT:PC71BM layer; a layer of P(T3-il)-2:PC71BM applied on the bilayer of chromium and MoO3; and Ca and Al electrode layer on the top.

Abstract: A method for increasing the speed of aerosol jet assisted printing a layered perovskite structure comprises applying a PEDOT:PSS layer to a substrate; applying an aerosol mist containing methylammonium iodide and lead iodide, with or without additives, atop the PEDOT:PSS layer with an aerosol jet nozzle; and holding the structure to form a methylammonium lead iodide (CH3NH3PbI3) perovskite thin film layer. The substrate may be an ITO glass or plastic substrate, and the PEDOT:PSS layer may be applied by a process selected from spin-coating, inkjet-printing, slot-die-coating, aerosol jet printing, physical vapor deposition, chemical vapor deposition, and electrochemical deposition. The aerosol mist is generated from a single ink comprising all the constituents of methylammonium lead iodide either dissolved or suspended in one or more compatible solvents or co-solvents. The holding of the CH3NH3PbI3 layer may be performed at about 25-120° C. or lower for 96 hours or less.

Abstract: A method for aerosol-jet printing a layered perovskite structure by applying a PEDOT:PSS layer to a substrate; applying a layer of lead iodide (PbI2) to the PEDOT:PSS layer; and applying an aerosol mist of methylammonium iodide (CH3NH3I) atop the PbI2 layer with an aerosol-jet nozzle to form a CH3NH3PbI3 perovskite film layer. The substrate may be an ITO glass substrate, and the PEDOT:PSS layer may be applied by a process selected from spin-coating, inkjet-printing, slot-die-coating, aerosol-jet printing, physical vapor deposition, chemical vapor deposition, and electrochemical deposition. The PbI2 layer may be applied by a process selected from spin-coating, aerosol-jet printing, inkjet-printing, slot-die-coating, physical vapor deposition, chemical vapor deposition, and electrochemical deposition, and the PbI2 for application to the PEDOT:PSS layer may be in a solution of DMF, DMSO, ?-butyrolactone, or a combination thereof.

Abstract: Techniques for fabrication of kesterite Cu—Zn—Sn—(Se,S) films and improved photovoltaic devices based on these films are provided. In one aspect, a method of fabricating a kesterite film having a formula Cu2?xZn1+ySn(S1?zSez)4+q, wherein 0?x?1; 0?y?1; 0?z?1; and ?1?q?1 is provided. The method includes the following steps. A substrate is provided. A bulk precursor layer is formed on the substrate, the bulk precursor layer comprising Cu, Zn, Sn and at least one of S and Se. A capping layer is formed on the bulk precursor layer, the capping layer comprising at least one of Sn, S and Se. The bulk precursor layer and the capping layer are annealed under conditions sufficient to produce the kesterite film having values of x, y, z and q for any given part of the film that deviate from average values of x, y, z and q throughout the film by less than 20 percent.

Abstract: A method for aerosol jet printing a layered perovskite structure comprises applying a PEDOT:PSS layer to a substrate; applying a layer of lead iodide (PbI2) to the PEDOT:PSS layer; and applying an aerosol mist of methylammonium iodide (CH3NH3I) atop the PbI2 layer with an aerosol jet nozzle to form a CH3NH3PbI3 perovskite film layer. The substrate may be an ITO glass substrate, and the PEDOT:PSS layer may be applied by a process selected from spin-coating, inkjet-printing, slot-die-coating, aerosol jet printing, physical vapor deposition, chemical vapor deposition, and electrochemical deposition. The PbI2 layer may be applied by a process selected from spin-coating, aerosol jet printing, inkjet-printing, slot-die-coating, physical vapor deposition, chemical vapor deposition, and electrochemical deposition, and the PbI2 for application to the PEDOT:PSS layer may be in a solution of DMF, DMSO, ?-butyrolactone, or a combination thereof. The annealing of the PbI2 layer may be performed at about 80° C. or lower.

Abstract: A layered perovskite structure comprising a substrate having an upper surface and a lower surface; and a layer of a perovskite film on the upper surface. A passivating layer may be applied to the upper surface of the substrate to which the perovskite film is attached. The passivating layer comprises at least one a chalcogenide-containing species with the general chemical formula (E3E4)N(E1E2)N?C?X where any one of E1, E2, E3 and E4 is independently selected from C1-C15 organic substituents comprising from 0 to 15 heteroatoms or hydrogen, and X is S, Se or Te, thiourea, thioacetamide, selenoacetamide, selenourea, H2S, H2Se, H2Te, or LXH wherein L is a Cn organic substituent comprising heteroatoms and X?S, Se, or Te. The substrate comprises PEDOT:PSS, and may further comprise a layered glass/ITO/PEDOT:PSS structure. A passivating layer is applied to the PEDOT:PSS layer, and a top electrode may be applied over the perovskite film.

Abstract: A method for making a layered perovskite structure comprises: a) performing a vapor assisted surface treatment (VAST) of a substrate with a surface passivating agent; b) applying a layer of PbI2 to the passivating agent; c) exposing the PbI2 to methylammonium iodide (CH3NH3I) in an orthogonal solvent; and d) annealing the structure. A PEDOT:PSS coated ITO glass substrate may be used. The surface passivation agent may be one a chalcogenide-containing species with the general chemical formula (E3E4)N(E1E2)N?C?X where any one of E1, E2, E3 and E4 is independently selected from C1-C15 organic substituents comprising from 0 to 15 heteroatoms or hydrogen, and X is S, Se or Te, thiourea, thioacetamide, selenoacetamide, selenourea, H2S, H2Se, H2Te or LXH wherein L is a Cn organic substituent comprising heteroatoms and X?S, Se, or Te. The passivating agent may be applied by spin-coating, inkjet-printing, slot-die-coating, aerosol-jet printing, PVD, CVD, and electrochemical deposition.

Abstract: A method of forming perovskite thin films with micron-sized perovskite grains is provided. A layer of PbX2 in a solution containing a metal ion additive is applied to a structure. The structure with the PbX2 layer is annealed a first time. The PbX2 is exposed to CH3NH3X in a solvent. The structure with the exposed PbX2 layer is annealed a second time resulting in a CH3NH3PbX3 layer. X is selected from a group consisting of Cl, Br, I, CN, and SCN.

Abstract: Techniques for fabrication of kesterite Cu—Zn—Sn—(Se,S) films and improved photovoltaic devices based on these films are provided. In one aspect, a method of fabricating a kesterite film having a formula Cu2?xZn1+ySn(S1?zSez)4+q, wherein 0?x?1; 0?y?1; 0?z?1; and ?1?q?1 is provided. The method includes the following steps. A substrate is provided. A bulk precursor layer is formed on the substrate, the bulk precursor layer comprising Cu, Zn, Sn and at least one of S and Se. A capping layer is formed on the bulk precursor layer, the capping layer comprising at least one of Sn, S and Se. The bulk precursor layer and the capping layer are annealed under conditions sufficient to produce the kesterite film having values of x, y, z and q for any given part of the film that deviate from average values of x, y, z and q throughout the film by less than 20 percent.

Abstract: Techniques for fabrication of kesterite Cu—Zn—Sn—(Se,S) films and improved photovoltaic devices based on these films are provided. In one aspect, a method of fabricating a kesterite film having a formula Cu2?xZn1+ySn(S1?zSez)4+q, wherein 0?x?1; 0?y?1; 0?z?1; and ?1?q?1 is provided. The method includes the following steps. A substrate is provided. A bulk precursor layer is formed on the substrate, the bulk precursor layer comprising Cu, Zn, Sn and at least one of S and Se. A capping layer is formed on the bulk precursor layer, the capping layer comprising at least one of Sn, S and Se. The bulk precursor layer and the capping layer are annealed under conditions sufficient to produce the kesterite film having values of x, y, z and q for any given part of the film that deviate from average values of x, y, z and q throughout the film by less than 20 percent.

Abstract: Techniques for fabrication of kesterite Cu—Zn—Sn—(Se,S) films and improved photovoltaic devices based on these films are provided. In one aspect, a method of fabricating a kesterite film having a formula Cu2?xZn1+ySn(S1?zSez)4+q, wherein 0?x?1; 0?y?1; 0?z?1; and ?1?q?1 is provided. The method includes the following steps. A substrate is provided. A bulk precursor layer is formed on the substrate, the bulk precursor layer comprising Cu, Zn, Sn and at least one of S and Se. A capping layer is formed on the bulk precursor layer, the capping layer comprising at least one of Sn, S and Se. The bulk precursor layer and the capping layer are annealed under conditions sufficient to produce the kesterite film having values of x, y, z and q for any given part of the film that deviate from average values of x, y, z and q throughout the film by less than 20 percent.

Abstract: Soluble chalcogenido clusters together with transition metal ions and main group elements are shown to provide gels having interconnected, open frameworks. Following supercritical drying with liquid carbon dioxide, the chalcogels may be converted to aerogels. The aerogels possess high internal surface areas with a broad pore size distribution that is dependent upon the precursors used and the aging conditions applied. Some of the gels are encompassed by formulas such as M4[M?4Qx]n, M4[M?2Qy]n, M4[M?Qx]n, M3[M?Qx]n, or Me2[M??Qx]n, where M is a divalent, trivalent, or tetravalent metal ion; M?, M?, and M?? are typically Ge, Sn, P, As, Sb, Mo, or W; and Q is typically S, Se, or Te. Methods of preparing the chalcogenido clusters are also provided.

Abstract: Soluble chalcogenido clusters together with transition metal ions and main group elements are shown to provide gels having interconnected, open frameworks. Following supercritical drying with liquid carbon dioxide, the chalcogels may be converted to aerogels. The aerogels possess high internal surface areas with a broad pore size distribution that is dependent upon the precursors used and the aging conditions applied. Some of the gels are encompassed by formulas such as M4[M?4Qx]n, M4[M?2Qy]n, M4[M?Qx]n, M3[M?Qx]n, or Me2[M??Qx]n, where M is a divalent, trivalent, or terravalent metal ion; M?, M?, and M?? are typically Ge, Sn, P, As, Sb, Mo, or W; and Q is typically S, Se, or Te. Methods of preparing the chalcogenido clusters are also provided.