Extended Data Fig. 5: Transient photoluminescence (PL) measurements of the undoped and Mn-doped PbSe/CdSe QDs.
From: Spin-exchange carrier multiplication in manganese-doped colloidal quantum dots
Two-dimensional plots of time- and spectrally-resolved PL of Mn-doped QDs (sample Mn-1) (a) and reference, undoped QDs (b). These data were collected using excitation with hvp = 3.1 eV and 〈Nph〉 < 0.1. In addition to the band-edge NIR emission from the core (hvPbSe = 0.83 eV), the Mn-doped sample exhibits a higher-energy NIR band at 1.28 eV (hvSE), which is absent for the undoped sample. This band emerges due to radiative spin-flip relaxation of the excited Mn ion which produces a NIR photon and a PbSe-core-based exciton (see main article). Instantaneous emission spectra of the doped (c) and the undoped (d) sample obtained from ‘a’ and ‘b’, respectively, by ‘slicing’ the two-dimensional plots at 10 ns. These spectra have been corrected for energy-dependent sensitivity of the detection system used in the measurements. The experimental spectra are fitted to Gaussian bands whose centres yield the positions of the PbSe core emission (hvPbSe, red) and the spin-exchange band (hvSE1, green). The Mn-doped QDs show both the hvPbSe and hvSE1 features, whereas the undoped QDs exhibit only the hvPbSe band.
