Fig. 4. Optical properties of assembled NPLs.
a Anisotropic emission properties of CdSe NPLs assembled at a liquid interface. Back focal plane imaging (experiment and theory) for two different assembly configurations (face down and edge up) showing the orientation of the emission dipole. Adapted from ref. 89. Copyright American Chemical Society 2017. b (bottom) Scheme of the FRET occurring in face-to-face stacked nanoplatelets. (middle–top) Microfluorescence images showing assemblies of stacked 5 ML NPLs. (top) Wide-field excitation shows the elongated shape of the assemblies. (middle) Localized laser excitation shows that the fluorescence extends beyond the excitation area (white circle) and demonstrates that the energy transfer occurs on large length scales. Adapted with permission from ref. 113. Copyright American Chemical Society 2020. c Effect of the number of layers on the emission spectra of NPL films. The onset of a second emission feature as the pump fluence intensity is increased is typical of amplified spontaneous emission. The gain threshold decreases as the number of layers increases. Adapted with permission from ref. 91. Copyright 2019 American Chemical Society.