TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the method, the first graphene oxide species comprises oxygen-containing groups attached to the first graphene oxide species and dispersed over a surface of the first graphene oxide species; and the heating step causes at least some of the oxygen-containing groups to rearrange and/or migrate to a different location on the surface of the graphene oxide. The heating step is performed at less than or equal to 125 degrees C, preferably less than or equal to 50 degrees C, for at least 5 days, preferably at least 20 days, and at a atmospheric pressure and/or at a pH of 7. In the method: the second graphene oxide species absorbs at least 20% more photons, preferably 40% more photons in the visible range than the first graphene oxide species, when placed under essentially identical conditions; the second graphene oxide species exhibits a sheet resistance of less than or equal to 1x 109 ohms/sq, preferably 1x 105 ohms/sq; the first graphene oxide species exhibits a first peak emission wavelength and the second graphene oxide species exhibits a second peak emission wavelength, where the second peak emission wavelength is at least 50 nm less or 100 nm less than the first peak emission wavelength; the second graphene oxide species exhibits a peak emission wavelength of less than or equal to 500 nm; the second graphene oxide species has a band gap of less than or equal to 5 eV, preferably less than or equal to 0.5 eV; the second graphene oxide species is arranged in a device and/or in contact with at least one electrode. Preferred Components: The atomic % (at.%) of oxygen in the second graphene oxide species is at least 50 at.%, preferably at least 90 at.% of at.% of oxygen in the first graphene oxide species, or the at.% of oxygen in the second graphene oxide species is greater than 20 at.%, preferably greater than 35 at.%. The second composition comprises: a first set of domains comprising carbon atoms substituted with oxygen-containing groups; and a second set of domains comprising carbon atoms that are substantially free of oxygen-containing groups, where the at.% of oxygen in the first set of domains is greater than or equal to 40 at.%, preferably greater than or equal to 50 at.%. The chemical reagent is a reducing agent and/or a strong base. The first and second compositions are in substantially solid form. The first and second compositions further comprise a fluid carrier, where the fluid carrier is a non-aqueous solution, an aqueous solution, or water. The oxygen-containing groups comprise epoxy groups, carboxy groups, carbonyl groups, lactol groups, and/or hydroxy groups. The composition exhibits a peak emission wavelength of less than or equal to 500 nm. In the composition, the at.% of oxygen of the graphene oxide species is greater than 20 at.%. EXAMPLE - No suitable example given.