Triplet sensitization by perovskite nanocrystals for photon upconversion

The potential of three-dimensional (3D) metal-halide perovskites to sensitize organic triplets is unveiled. Nanocrystals of surface-modified inorganic cesium lead halide perovskites (CsPbX3, X = Br/I) are found to work as efficient triplet sensitizers for photon upconversion based on triplet–triplet annihilation (TTA-UC) at low excitation intensity.