| A remarkable example of E-type delayed fluorescence has been discovered in colloidal nanocrystals. This talk will describe the synthesis and spectroscopy of colloidal Mn2+-doped semiconductor nanocrystals that show pronounced intrinsic high-temperature dual emission arising from fast population exchange between luminescent Mn2+ and excitonic excited states of the same nanocrystal. The emission spectrum is strongly temperature dependent, reflecting thermal control of population distributions between the two emissive states. The temperature window over which pronounced dual emission is observed can be tuned by changing the energy gap between the two states during growth. The ratio of the two intensities is independent of nonradiative effects. This new class of intrinsic dual emitters is shown to be attractive for ratiometric optical thermometry and thermography. |
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