Abstract
Light switches: UV irradiation induces Rhodamine B (RhB) aggregation into nanoparticles and changes RhB photoluminescent emissions from yellow to white light (see graphic). The UV-induced changes are reversible. A novel approach to generate organic fluorescent nanoparticles and to prepare white-light-emitting fluorescent materials is demonstrated. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.