Architectural tuning of color chromaticity by controlled nonradiative resonance energy transfer in CdTe nanocrystal solids

In recent years, precisely tuning shades of white across color chromaticity diagram has become critically important in solid state lighting, especially to achieve application specific spectrally tuned illumination [1]. In this respect, semiconductor quantum dot nanocrystals (NCs) have attracted significant attention for their use as luminophors in light-emitting diodes (LEDs). This is mainly because it is possible to conveniently control the electronic structure of these nanocrystals by adjusting their size, shape, and composition [2]. However, such tuning is only limited to the process of nanocrystal synthesis in which the size, shape, and composition are controlled. Here we propose and demonstrate an alternative, post-synthesis, architectural approach to tune the color of nanocrystal emitters by controlling their radiative decay kinetics and steady state spontaneous emission using nonradiative Förster resonance energy transfer (FRET). For the proof-of-concept demonstration of such FRET-controlled tuning, we constructed nanocrystal solids that are layer by layer assembled with interlayer spacings between them precisely controlled at the nanoscale [3].