TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The n-type material comprises fullerene derivative(s) of formula Fasterisk-(R)n and its solvates, salts, and mixtures.n= greater than or equal to 1;Fasterisk=comprises fullerene having a surface, which comprises 6-membered and 5-membered rings;andR=comprises at least one optionally substituted, optionally saturated, carbocyclic, or heterocyclic first ring, which directly bonds to fullerene (preferably indene, naphthyl, Ph, pyridinyl, quinolinyl, cyclohexyl, or cyclopentyl (all optionally substituted)).The first solvent comprises toluene, o-xylene, m-xylene, p-xylene, and/or tetralin. The second solvent comprises salicylaldehyde, methylsalicylate, anisol, tetralin, cyclopentane, cyclopentanone, cyclohexanone, methylbenzoate, anisaldehyde, mesitylene, and/or 2-methoxybenzaldehyde. Preferred Composition: The active layer ink composition comprises second solvent (0.01-10 wt.%). Preferred Parameter: The second solvent has a dispersion Hansen solubility parameter of 15-20 MPa0.5; polarity Hansen solubility parameter of 5-15 MPa0.5; and hydrogen bonding Hansen solubility parameter of 0.5-18 MPa0.5.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The p-type material comprises regioregular polythiophene derivative(s). Preferred Method: The method further comprises annealing the active layer ink composition after the composition is applied to the surface at a temperature and duration to evaporate greater than or equal to 99 wt.% of the first and second solvents. EXAMPLE - An active layer ink composition was made, in an inert atmosphere, by dissolving poly-3-hexylthiophene (18.90 mg) and indene di-substituted 60C fullerene (18.90 mg) in a solvent system including salicylaldehyde (0.09 g) and toluene (2.07 g). The active layer ink was placed on a shaker at 70 degrees C overnight, to allow the material to completely dissolve before the active layer deposition. The efficiency of photovoltaic device having an active layer formed using the resulting active layer ink composition was 5.12%.