Photoswitching of triplet-triplet annihilation upconversion showing large emission shifts using a photochromic fluorescent dithienylethene-Bodipy triad as a triplet acceptor/emitter.
A photoswitchable fluorescent triad based on dithienylethene and Bodipy was used as a triplet acceptor/emitter for reversible photoswitching of triplet-triplet-annihilation upconversion (with Pd(II) tetraphenyltetrabenzoporphyrin as a triplet photosensitizer), which shows green/near IR emission changes with an emission energy difference of 0.79 eV (Δλ = 268 nm).