Mechanically controlled FRET to achieve an independent three color switch

A high color contrast mechanochromic blend TP-1/Rh-2 was constructed from the two components of a triphenylacrylonitrile derivative TP-1 (donor) and a rhodamine B derivative Rh-2 (acceptor). A reversible and independent three color switch was achieved by the stimulus of external force at ambient temperature. The crucial point for realizing the tricolored switch with a high color contrast is dependent on mechanically controlled FRET to suppress the emission crosstalk between the Y phase of TP-1 and the R phase of Rh-2.