Pyrene as emitting chromophore in organic–inorganic lead halide-based layered perovskites with different halides

The absorption, emission and excitation spectra of layered perovskites consisting of inorganic layers of lead halide and organic layers with the chromophore pyrene are investigated. The emitting species is the organic chromophore. By variation of the halide composition in the inorganic layer, one can shift the energy of the inorganic excitonic band in these compounds. This also has an influence on the chromophore phosphorescence in the organic layer. Its triplet lifetime and its excimeric emission in the presence of the different halides is discussed in terms of the heavy-atom effect, the crystal structure and an efficient energy transfer between the organic and inorganic layers.