Directing Singlet and Triplet Energy Transfer Pathways in Halide Perovskite QD-Chromophore Assemblies

Semiconductor-multiple chromophore hybrids modulated through bandgap engineering also allow switching from down conversion to upconversion of the incident light. By carefully selecting the donor (CsPbBr₃ or CsPbI₃ ) we can either induce down conversion with singlet energy cascade in CsPbBr3-Rubrene-Perylene dye films, or upconversion with triplet-triplet annihilation in Perovskite-rubrene-perylene dye films. The primary step in these two examples is either singlet or triplet energy transfer between excited perovskite nanocrystal and the dye. Factors such as bandgap energy of the semiconductor, energy levels of acceptor and spectral overlap between donor emission and acceptor absorption play a major role in dictating the mechanism of energy transfer. The factors that control the energy transfer pathways will be discussed. Identifying optimum conditions of energy transfer pathways and ability to tune individual energy transfer steps can enable the design of multi chromophore assembly for designing light harvesting assembly or display devices.