In many aggregates or solids of fluorophores, fluorescence tends to be quenched . Optical properties of monomer, dimer and trimer in solution were studied in depth for known fluorophores, such as rhodamine G , that elucidated lowered quantum efficiencies for aggregates. Isolated fluorophore in solids or in diluted solutions can therefore exhibit enhanced emission. On the other hand, there are interesting cases in which fluorescence is enhanced or induced by aggregation .