Tsokkou, Demetra Yu, Xiaoyun Sivula, Kevin Banerji, Natalie 2016-10-13 Solution-processed semiconducting transition metal dichalcogenides are emerging as promising two-dimensional materials for photovoltaic and optoelectronic applications. Here, we have used transient absorption spectroscopy to provide unambiguous evidence and distinct signatures of photogenerated excitons and charges in solution- processed few-layer MoS₂ nanoflakes (10–20 layers). We find that photoexcitation above the direct energy gap results in the ultrafast generation of a mixture of free charges in direct band states and of excitons. While the excitons are rapidly trapped, the free charges are long-lived with nanosecond recombination times. The different signatures observed for these species enable the experimental extraction of the exciton binding energy, which we find to be ∼80 meV in the nanoflakes, in agreement with reported values in the bulk material. Carrier-density-dependent measurements bring new insights about the many-body interactions between free charges resulting in band gap renormalization effects in the few-layer MoS₂ nanoflakes. application/pdf https://folia.unifr.ch/global/documents/305233 https://folia.unifr.ch/documents/305233/files/ban_ref.pdf https://folia.unifr.ch/documents/305233/files/ban_ref_sm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1021/acs.jpcc.6b09267 info:eu-repo/semantics/openAccess License undefined The Journal of Physical Chemistry C. - 2016, vol. 120, no. 40, p. 23286–23292 info:eu-repo/classification/udc/54 The role of excitons and free charges in the excited-state dynamics of solution-processed few-layer MoS₂ nanoflakes http://purl.org/coar/resource_type/c_6501