Fig. 1: Design of QDs-hydrogel integrated grating for directional PL emission and radiation control.
From: Switchable unidirectional emissions from hydrogel gratings with integrated carbon quantum dots
a Schematic of the designed architecture for steering the guided mode emission into free space. The in-plane momentum k// of QDs emission could be redirected and coupled to leaky waves due to the grating momentum kG accumulation from hydrogel grating. The excitation wavelength is 532 nm (green) and the PL peak wavelength is 575 nm (orange). b Operation principle for unidirectional emission and radiation control. The spatial location of the excitation manipulates the direction of in-plane momentum for passing through the grating. The grating efficiency could be tuned by changing the relative humidity around the sample due to the hydrogel morphology alteration, enabling the radiation energy switch. The inset represents the phase change of hydrogel grating and the PL energy variation under middle RH (red) and high RH (golden) conditions.
