Optical properties and carrier dynamics in transition metal dichalcogenides and halide perovskites (Conference Presentation)

Atomically thin transition metal dichalcogenides (TMDs) and halide perovskites have rapidly grown as promising materials for efficient optoelectronic devices. In both material classes, the dynamics of optical excitations and their interactions on ultrafast timescales are still debated. Using a newly developed theory, we discuss the interaction of TMD excitons and unbound charge carriers with optical phonons in the dielectric environment of the 2d layer. We find a significant reduction of exciton binding energies as well as linewidth broadening due to the dynamical coupling to environmental phonons. Moreover, we investigate near-band-edge optical transitions in CsPbBr3 single crystals at room temperature by combining ultrafast two-dimensional electronic spectroscopy and semiconductor Bloch equation calculations. An exciton binding energy of ~30 meV and remarkably short <30-fs carrier relaxation rates are extracted.