TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Cell: In the photovoltaic cell, the conductive layer is counter electrode of the cell. The counter electrode is connected to a conductive support layer either directly, or through a current collector connected to an external current. The photovoltaic cell is free of scaffold structure layer. The photovoltaic cell is deposited on a conductive glass substrate.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Element: The element is Ce, Pr, Gd, Eu, Tb, Dy, Er, Tm, Nd or Yb. Preferred Components: The metal cation is selected from metal element of Groups IIIB, IVB, VB, VIB, VIIB, VIIIB, IB, IIB, IIIA, IVA and VA of block d of the Periodic Table of the Elements. The metal cation is Li, Mg, Na, K, Rb, Cs, Be, Ca, Sr, Ba, Sc, Ti, V, Cr, Fe, Ni, Cu, Zn, Y, La, Zr, Nb, Tc, Ru, Mo, Rh, W, Au, Pt, Pd, Ag, Co, Cd, Hf, Ta, Re, Os, Ir, Hg, B, Al, Ga, In, Tl, C, Si, Ge, Sn, Pb, P, As, Sb, Bi, O, S, Se, Te or Po. The metal cation is a transition metal selected from Groups IIIB, IVB, VB, VIB, VIIB, VIIIB, IB and IIB of block d Periodic Table. The transition metal is a metal selected from Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Mo, Rh, W, Au, Pt, Pd, Ag, Mn, Co, Cd, Hf, Ta, Re, Os, Ir and Hg. The metal cation is a post-transition metal selected from Group IIIA, IVA and VA. The metal cation is Al, Ga, In, Tl, Sn, Pb, or Bi. The metal cation is a semi-metal selected from Group IIIA, IVA, VA and VIA. The metal cation is B, Si, Ge, As, Sb or Po. The metal cation is an alkali metal selected from Group IA. The metal cation is an alkali metal Li, Mg, Na, K, Rb or Cs. The metal cation is an alkaline earth metal selected from Group IIA. The metal cation is Be, Ca, Sr or Ba. The metal cation is a lanthanide element. The metal cation is an actinide element. The actinide element is Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No or Lr. The metal cation is a divalent metal cation. The divalent metal is selected from Cu+2, Ni+2, Co+2, Fe+2, Mn+2, Cr+2, Pd+2, Cd+2, Ge+2, Sn+2, Pb+2, Eu+2 and Yb+2. The metal cation is a trivalent metal cation. The trivalent metal is Bi+3 or Sb+3. The metal cation is Pb+2. The anion is selected from anions of an atom selected from S, Se, and Te. The anion is selected from acetate (CH3COO-), formate (HCOO-), oxalate (C2O4-2), and cyanide (CN-). The anion is a oxoanion selected from AsO4-3, AsO3-3, CO3-2, HCO3-, OH-, NO3-, NO2-, PO4-3, HPO4-2, SO4-2, HSO4-, S2O3-2, SO3-2, ClO4-, ClO3-, ClO2-, OCl-, IO3-, BrO3-, OBr-, CrO4-2, and Cr2O7-2. The anion is selected from Br-, I-, NCS-, CN- and NCO-. The anion is selected from IBr-3, Cl2I-3, Br2I-3 and I2Cl-3. The metal is selected from gold, silver, copper, platinum, nickel, palladium, titanium, and iridium. The protective layer is an inorganic material or a metal oxide layer. The protective layer is an anti-reflecting layer. The protective layer is of a dielectric material. The protective layer is ITO or FTO. The metal oxide is selected from SiO, SiO2, Si3N4, TiO2, Ta2O5, Al2O3, ZrO2, Nd2O3, MgF2, MgO, SrF2, ZnO, MoO3, In-ZnO and Hf2O. The protective layer is a moisture barrier. Preferred Substrate: The substrate is an inorganic semiconductor material selected from silicon, tin, compounds of boron, tellurium, geranium, gallium, gallium arsenide (GaAs), gallium phosphide (GaP), cadmium telluride (CdTe), gallium aluminum arsenide (GaAlAs), indium phosphide (InP), gallium arsenide phosphide (GaAsP), cadmium sulfide (CdS), copper indium gallium diselenide (CIGS), mercury cadmium telluride (HgCdTe), and copper indium sulfide or selenide. The substrate is selected from glass, porous glass, quartz, indium tin oxide (ITO), fluorinated tin oxide (FTO), antimony doped tin oxide (ATO), mica, SrGeO3 and zinc oxide. The substrate is selected from SnO2:F, SnO2:Sb, In2SO3:Sn, ZnO:Al, ZnO:Al2O3, and ZnO:Ga2O3. The substrate is indium tin oxide (ITO) or fluorinated tin oxide (FTO). The substrate is a carbon substrate or HOPG (graphite). The substrate is or comprises a metal. The substrate comprise a transition metal selected from Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Mo, Rh, W, Au, Pt, Pd, Ag, Mn, Co, Cd, Hf, Ta, Re, Os, Ir, and Hg. The substrate is a glass or a plastic substrate composed of a glass material coated with a conductive material or metal nanoparticles. The conductive layer is or comprises a metal, a transition metal or a metal alloy, where the metal is Au or Ag. The conductive layer is or comprises a carbon substrate or HOPG (graphite). The conductive layer is or comprises an inorganic semiconductor material, including silicon, tin, compounds of boron, tellurium, geranium, gallium, gallium arsenide (GaAs), gallium phosphide (GaP), cadmium telluride (CdTe), gallium aluminum arsenide (GaAlAs), indium phosphide (InP), gallium arsenide phosphide (GaAsP), cadmium sulfide (CdS), copper indium gallium diselenide (CIGS), mercury cadmium telluride (HgCdTe), and copper indium sulfide or selenide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Element: The element is devoid of a scaffold layer. The element is flexible. The element is formed at low temperatures. The element is in a solid state. Preferred Substrate: The substrate is a flexible or rigid substrate, selected amongst two-dimensional and a three-dimensional surface. The substrate is a solid material selected from glass, paper, semiconductor inorganic or organic material, a polymeric material and a ceramic surface. The substrate is flexible, conductive and transparent. Preferred Components: The perovskite layer on the substrate provides a planar junction. The perovskite layer is positioned directly on the substrate. The perovskite is an organic-inorganic hybrid material. The perovskite material is a three-dimensional material or a two-dimensional material. The perovskite material is of formula selected from AMX3, AMX4, A2MX4, A3MX5, A2A'MX5 and AMX3-nX'n. The organic cation comprises at least one organic moiety. The organic moiety is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, heterocyclyl, -NR1R2, -OR3, -SR4, -S(O)R5, alkylene-COOH, or ester (all optionally substituted). The perovskite is one species of a perovskite material. The perovskite is a combination of several different species of different perovskite materials. The number of different species of different perovskite materials is 2-10 different perovskite species. The perovskite layer is a multilayer structure of layered perovskite materials, where each layer is different and comprises either a different species of a perovskite material, or a different mixture of several different species of perovskite materials. Each layer in a perovskite multilayer is made of a different combination or the same combination but with different ratios of perovskite materials. The multilayer perovskite comprises 2-10 perovskite layers. The anion is a halide anion, a chalcogenide anion, an organic anion or an oxoanion. The anion is selected from O-2, N-3, or S-2. The anion is a halide anion. The perovskite material is an organic-inorganic perovskite hybrid. In an organic-inorganic perovskite hybrid, the organic cation is an organic monovalent cation; the organic cation is a primary, a secondary, a tertiary or a quaternary organic ammonium compound; and the organic cation is a carbon (hydrocarbon) chain comprising at least one heteroatom selected from N, O and S, preferably N. The carbon chain comprises halogens, a heterocyclyl or heteroaryl. The organic cation is a primary, a secondary, a tertiary or a quaternary organic ammonium compound having two positively charged nitrogen atoms. The organic cation is selected from (RR1R2R3N)+. The cation is selected from RNH3, RR1NH2, RR1R2NH, or NH3RNH3. The cation is selected from RNH=R1, NH2=R, RN=R1R1, R1=N=R, RR1N=R=NR2R3, H2N=R=NH2, and RR'n=CHNR2R3. The cation is (H2N=CHNH2)+. The perovskite material is of formula AMX3, AMX'X2, and RNH3MX'X2. The perovskite material comprises or is selected from CH3NH3PbF3, CH3NH3PbCl3, CH3NH3PbI3, CH3NH3PbBr3, CH3NH3PbBrI2, CH3NH3PbBrCl2, CH3NH3PbIBr2, CH3NH3PbICl2, CH3NH3PbClBr2 and CH3NH3PbI2Cl. The perovskite material comprises or is selected from CH3NH3SnICl2, CH3NH3SnBrI2, CH3NH3SnBrCl2, CH3NH3SnF2Br, CH3NH3SnIBr2, CH3NH3SnF2I, CH3NH3SnClBr2, CH3NH3SnI2Cl and CH3NH3SnF2Cl. The perovskite material is of the formula RNH3MX3. The perovskite material comprises or is selected from CH3NH3PbF3, CH3NH3PbCl3, CH3NH3PbI3 and CH3NH3PbBr3, preferably CH3NH3PbI3. The perovskite material is of formula (NH2=CH-NH2)MX3. The perovskite material comprises or is selected from (NH2=CH-NH2)PbBr3, (NH2=CH-NH2)PbI3, (NH2=CH-NH2)PbCl3, (NH2=CH-NH2)PbFCl2, (NH2=CH-NH2)PbBrCl2, (NH2=CH-NH2)PbICl2, (NH2=CH-NH2)PbFCl2, (NH2=CH-NH2)PbFBr2, (NH2=CH-NH2)PbFI2 and (NH2=CH-NH2)PbIBr2. The perovskite material is of formula M'MX'X2. The perovskite material comprises or is selected from CsPbI2Cl, CsPbICl2, CsPbI2F, CsPbIF2, CsPbI2Br and CsPbIBr2. The perovskite material comprises or is selected from CsSnI2F, CsSnIF2, CsSnI2Cl, CsSnICl2, CsSnI2Br and CsSnIBr2. The additional layer is not a scaffold layer. The additional layer is positioned (a) between the perovskite layer and the substrate; and/or (b) between the perovskite layer and the conductive layer; and/or (c) between at least two perovskite layers. The additional layer is a protective layer. The additional layer is a hole-transport material. The hole transport material is made of a conductive polymer. The element excluding the substrate is flexible. The heterojunction is in a solid state.A and A'=organic cation or metal cation;M=metal cation;X and X'=anions;n=0-3;R, R1, R2 and R3=H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, heterocyclyl, halo, alkylene-COOH, ester, -OH, -SH, or -NH.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The substrate is formed of a polymeric material (conductive polymer), selected from polyazulenes, polyphenylenes, polypyrenes, polynaphthalenes, polyester (PET), polyimide, poly(pyrrole)s, (PPY), poly(thiophene)s (PT), poly(3,4-ethylenedioxythiophene) (PEDOT), polyazepines, polyindoles, polycarbazoles, poly(p-phenylene vinylene) (PPV), Poly(acetylene)s (PAC), poly(p-phenylene sulfide) (PPS), poly-3-hexyl thiophene (P3HT) and polyanilines. The protective layer comprises fluorinated polymers.