TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Parameters: All particles in dispersion have size of less than or equal to 200 nm. Number average particle size of particles in aqueous dispersion is 10-50 nm, preferably 10-20 nm. Preferred Processes: Layer is deposited using drop casting, spin coating, slot die coating, inkjet printing, spray coating, flexographic printing, gravure printing, or another scalable deposition technique. Aqueous dispersion is prepared by producing dispersion of photoactive organic substance and fullerene in liquid comprising water and tetrahydrofuran (THF) or another auxiliary solvent in which organic substance is soluble and auxiliary solvent is inter-miscible with water, thereafter removing THF from dispersion before applying dispersion to surface of substrate. Dispersion is produced by mixing 1st dispersion and 2nd dispersion in which 1st dispersion is dispersion of photoactive organic substance in liquid comprising water and THF or another auxiliary solvent and 2nd dispersion is dispersion of fullerene in liquid comprising water and THF or another auxiliary solvent. Preferred Compositions: Fullerene is bucky ball fullerene, preferably selected from underivatized Buckminster fullerene, derivatized Buckminsterfullerene, underivatized 70 carbon bucky ball fullerene, and derivatized 70 carbon bucky ball fullerene in which derivatives may be selected from aryl-fullerene-carboxylic acids, aryl-fullerene-esters, indene-fullerene adducts, perylene derivatives, and tetrabenzoporphyrin derivatives. Weight to weight ratio of THF or other auxiliary solvent to water before removal of THF or other auxiliary solvent is 5:95-50:50, preferably 10:90-30:70.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compositions: Aqueous dispersion comprises greater than or equal to 0.02 wt.%, preferably 0.02-1 wt.% photoactive organic polymer and greater than or equal to 0.02 wt.%, preferably 0.02-1 wt.% fullerene. Photoactive organic substance is selected from polythiopenes, such as poly(3-hexylthiophene), poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene) (MDMO-PPV), poly-benzodithiazoles, poly-vinyl carbazoles, polypiridines, poly-benzodithiophenes, poly-phenylenes, poly-para-phenylenes, poly-fluorenes, poly-pyrroles, and their copolymers.