TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: The method comprises: the step of removing solvent if there is a solvent present in the organic charge transporting composition before application to the optionally sensitized surface of the semiconductor; and the step of increasing the viscosity of the liquid hole conducting material by gelling, crosslinking and/or polymerizing the liquid charge transporting material, following the step of applying the liquid charge transporting material to the optionally sensitized surface of the semiconductor. The liquid charge transporting material is applied onto the surface of the semiconductor by pouring. The counter-electrode is applied before the step of applying the solvent-free, liquid charge transporting composition, so as to provide a solar cell comprising an inner, air-occupied space. The solvent-free, liquid charge transporting composition is applied through a hole in an electrode of the solar cell. The charge transporting material is liquid at a temperature of less than or equal to 150 degrees C, preferably less than or equal to 25 degrees C. Preferred Components: The charge transporting material has the capacity of transporting charges by electronic motion and/or charge hopping. The charge transporting composition does not transport charges by material migration. The charge transporting composition comprises 70-100 wt.% of the organic charge transporting material. The charge transporting composition comprises further components (a) one or more dopants, (b) one or more solvents, and (c) one or more other additives such as ionic compounds. The charge transporting material is non-charged during the method of preparing the solar cell. The charge transporting material has a viscosity of less than 15000 cPs (centipoises) when measured with a Brookfield DV-II+ viscosimeter on 0.5 ml of sample at the indicated temperature. The solar cell comprises a semiconductor electrode comprising a layer of the semiconductor, the counter electrode opposed to the semiconductor electrode, and a charge transporting layer disposed between the semiconductor electrode and the counter electrode, where the charge transporting layer is provided by the charge transporting composition. The solar cell is a dye-sensitized solar cell. Preferred Components: The liquid charge transporting material has a structure of formulae ((R1a)x-A-(R1p)z) (I), ((R1a)x-(A)v(-R1p)z-N-(R)w) (II), (-(-A(-R(a/b))x/z-N(-A1-(R1(a/b)))-A2(-R2(a/b))-)n-) (III), (-(-A(-R(a/b)x/z)-N(-A1-(R1(a/b))x/z)-A2(-R2(a/b))x/z-N(-A3-(R3(a/b))x/z)-A4(-R4(a/b))x/z)-)n-) (IV), and/or (-(-A(-R(a/b)x/z-N(-A1-(R1(a/b))x/z)-A2(-R2(a/b))x/z-A3(-(R3(a/b))x/z)-N(-A4-(-R4(a/b))x/y)-)n-) (V).n = 1-20;A = a mono-, or polycyclic system comprising at least one pair of a conjugated double bond (-C=C-C=C-), where the cyclic system optionally comprises one or several heteroatom, and optionally substituted;A1-A4 (if present) = A;v = 1-3;(R)w = a hydrocarbon residue comprising 1-30C (optionally substituted and optionally comprising 1 or several heteroatom);w = 0-2;R1a = an alkyl or a residue comprising one or several O atoms, where the alkyl and/or O atom comprising residue is optionally halogenated;x = 0 to a maximum possible number of substituents of a respective A comprising the number x of other residues R1a linked to another A optionally present;R1p = an optional residue enabling a polymerization reaction with compounds comprising structure (I-V) used as monomers, and/or a crosslinking between different compounds comprising structures (I-V), where R1p is linked to an N-atom, to an A and/or to a substituent R1p of other structures according (I-V), resulting in repeated, crosslinked and/or polymerized moieties of (I-V);z = 0-2 or number of other residues R1p linked to another A optionally present; andR(a/p)x/z, R1-4(a/p)x/z = R1a or R1p.Provides that: In (I)-(V), at least one R1a is an oxygen containing residue; and two or more R1a may form an oxygen-containing ring; and v+w does not exceed 3, and, if w is 2.