Transient absorption measurements on Zn3N2 colloidal quantum dots
These transient absorption data were acquired from 3 samples of Zn3N2 colloidal quantum dots with different diameters using a system comprising a Helios (Ultrafast Systems LLC) spectrometer, an ultrafast Ti:sapphire amplifier system (Spectra Physics Solstice Ace) and an optical parametric amplifier (Topas Prime) with an associated NIR-UV-Vis unit. This system generated 100 fs pump pulses at 375 nm with a beam diameter of 240 μm. The pulse energy could be reduced using a series of reflective neutral density filters to give pump fluences from 1×1014 to 3.5×1015 photons·per cm2 per pulse. A white light continuum generated by the same laser system which was used as the probe to record changes in absorption between 430 and 913 nm. The samples were magnetically stirred to avoid photocharging effects during the measurements. Steady state absorbance spectra were acquired periodically to monitor and account for changes in absorbance due to oxidation of the Zn3N2 QDs.