Fig. 1: Proposed concept for full-color tuning with a single-wavelength excitation.
From: Full-color tuning in multi-layer core-shell nanoparticles from single-wavelength excitation
a Schematic of up-transition and decay processes in a sensitizer–actator (S-A) coupled system with characteristic rise time (τRt) and decay time (τDt) for an upconverted emission. ET, ETU, Ex, and Em stand for energy transfer, energy transfer upconversion, excitation, and emission, respectively. |A0-2> and |S0,1> stand for energy levels of S and A dopants, respectively. b Schematic of tuning RGB colors through continuous wave (c.w.) (or long pulse, LP) and short pulse (SP) excitations, and time-gating technique. The c.w. (or LP) is used for the emission with a longer rise time, SP for the emission with a shorter rise time, and time-gating for the longer decay emission. c Proposed multi-layer core-shell (MLCS) nanostructure consisting of two complementary luminescent layers for full-color tuning under a single excitation wavelength with suitable modulation modes.
