Uniting aggregation-induced emission and stimuli-responsive aggregation-caused quenching, single molecule achieved multicolour luminescence

A single molecule with multicolour luminescence, especially white emission, is crucial for developing luminescent materials, but it is arduous to be obtained. Herein, we proposed a facile method to fabricate an intriguing single molecule by uniting aggregation-induced emission (AIE) and stimuli-responsive aggregation-caused quenching (ACQ) fluorophores for continuous adjustment of multicolor luminescence. Such a method overcame the challenge and readily achieved a broad, continuous and distinguishable multicolour fluorescence by dual regulation (pH and water fraction) only. By simply tuning pH and water fraction, AIE, ACQ and FRET (fluorescence resonance energy transfer) effects were synergistically regulated, which enabled us to continuously produce over six luminescent colours including orange-red, orange, white, blue, cyan and green. Significantly, the quantum yield of white-light emission with Commission International de L'Eclairage (CIE) coordinates of (0.31, 0.29) could reach up to 12.2%. Furthermore, this unimolecular entity could be applied for multicolour gels and multichannel cell imaging with preferable stability, flexibility and versatility. Particularly, the innovative design concept of synergistically uniting AIE and a responsive ACQ chromophore paves a new way for multifunctional materials in colour-on-demand fields.