Activating room-temperature phosphorescence of 1,8-naphthalimide by doping into aromatic dicarboxylic acids

The room-temperature phosphorescence of 1,8-naphthalimide was activated by doping it into aromatic dicarboxylic acids. The doping system gives a bright yellow afterglow and 1,8-naphthalimide and isophthalic acid (0.02 mol% doping content) afford a phosphorescent lifetime of 403 ms and a quantum yield of 4.2%. Both energy transfer from the host to the guest and the formation of an intermolecular hydrogen-bonding network are responsible for the observed efficient and long-lived phosphorescence. The parent 1,8-naphthalimide, which is otherwise room-temperature phosphorescence inert, was activated by doping into aromatic dicarboxylic acids, leading to efficient and long-lived phosphorescent emission.