NOVELTY - A method (M1) of processing a solution involves processing a solution comprising a compound (E1) to form a photoactive layer, where the compound (E1) is selected from alkane (substituted by halo, cyano, carboxylic acid or alkyl carboxylate), cyclopentadithiophene, fluorine, thiophene, benzothiadiazole, naphthalene, and 1,2,3,4-tetrahydronaphthalene (all optionally substituted).    USE - For forming a photoactive layer which is useful in photovoltaic cells (claimed), photovoltaic modules to transfer energy in the form of light into energy in the form of electricity; and for preparing other electronic devices and systems including organic semiconductive devices, such as field effect transistors, photodetectors (e.g. infrared (IR) detectors), photovoltaic detectors, imaging devices (e.g. red green blue (RGB) imaging devices for cameras or medical imaging systems), light emitting diodes (LEDs) (e.g. organic LEDs or IR or near IR LEDs), lasing devices, conversion layers (e.g. layers that convert visible emission into IR emission), amplifiers and emitters for telecommunication (e.g. dopants for fibers), storage elements (e.g. holographic storage elements), and electrochromic devices (e.g. electrochromic displays).    ADVANTAGE - The processing additive selectively dissolves the electron acceptor material, but does not dissolve the electron donor material (e.g. a polythiophene such as poly(3-hexylthiophene) (P3HT)). As such, when the coating composition containing such a processing additive is applied to a surface to form a photoactive layer, the processing additive facilitates phase separation between the electron acceptor material and the electron donor material in the photoactive layer and therefore enhances the efficiency of the photovoltaic cell thus formed. The processing additive has a higher boiling temperature than the solvent in the coating composition and during the drying of the coating composition to form a photoactive layer, the electron acceptor material tends to remain in solution longer than the electron donor material, thereby facilitating phase separation between these two photoactive materials and resulting in an enhanced efficiency of the photovoltaic cell thus formed. The processing additive can reduce the need of post-processing (e.g. temperature annealing or solvent annealing) of photoactive layer. The photoactive layers exhibits finer domain size and more elongated domains.    DETAILED DESCRIPTION - A method (M1) of processing a solution involving processing a solution comprising a compound (E1) to form a photoactive layer, where the compound (E1) is selected from alkane (substituted by halo, CN, or COOR'), cyclopentadithiophene, fluorine, thiophene, benzothiadiazole, naphthalene, and 1,2,3,4-tetrahydronaphthalene (all optionally substituted by 1-10C alkyl).    R'=H or 1-10C alkyl.    INDEPENDENT CLAIMS are included for the following:    (1) a composition (C1) comprising a polymer, and the compound (E1), or a compound containing a substituted alkane, where at least one substituent on the alkane is not SH;    (2) an article comprising a substrate, and the composition (C1), where the composition (C1) is supported by the substrate; and    (3) an article (A1) comprising first and second electrodes, and a photoactive layer between the first and second electrodes, where the photoactive layer contains at least two separated phases, at least one of the separated phases having an average grain size of at least 20 nm; and the article (A1) is configured as a photovoltaic cell.