Saturation of Exciton Absorption in CdSe/CdS Nanoplatelets under Transient Excitation Conditions

Determination of the Single-Exciton Two-Photon Absorption Cross Sections of Semiconductor Nanocrystals through the Measurement of Saturation of Their Two-Photon-Excited Photoluminescence

“…This discrepancy may have been due to the fact that an extremely large pump fluence is usually used in measuring TPE processes (1 mJ per 30-μm spot for 110 fs). In this case, the pump fluence may be orders of magnitude higher than that required to generate up to 20 excitons in one NPL. , Therefore, TPACS estimation by the z -scan method may reflect not only the probability of generation of one exciton, but also a superposition of these probabilities for each of the multiple excitons generated in individual NPLs. However, despite the high probability of multiple exciton generation in NPLs, the PL QY and lifetime of multiexciton states in SNCs are very low .…”

“…Another significant disadvantage of the z -scan method as applied to SNCs is the possible generation of several exciton states simultaneously in one nanoparticle . For example, the number of exciton states per NPL may reach 20 . Thus, the number of absorption events per laser pulse can be much larger than the number of nanocrystals.…”

“…15 For example, the number of exciton states per NPL may reach 20. 16 Thus, the number of absorption events per laser pulse can be much larger than the number of nanocrystals.…”