Controlling the dimension of the quantum resonance in CdTe quantum dot superlattices fabricated via layer-by-layer assembly

Abstract

In quantum dot superlattices, wherein quantum dots are periodically arranged, electronic states between adjacent quantum dots are coupled by quantum resonance, which arises from the short-range electronic coupling of wave functions, and thus the formation of minibands is expected. Quantum dot superlattices have the potential to be key materials for new optoelectronic devices, such as highly efficient solar cells and photodetectors. Herein, we report the fabrication of CdTe quantum dot superlattices via the layer-by-layer assembly of positively charged polyelectrolytes and negatively charged CdTe quantum dots. We can thus control the dimension of the quantum resonance by independently changing the distances between quantum dots in the stacking (out-of-plane) and in-plane directions. Furthermore, we experimentally verify the miniband formation by measuring the excitation energy dependence of the photoluminescence spectra and detection energy dependence of the photoluminescence excitation spectra.

Anisotropic nanocrystal superlattices overcoming intrinsic light outcoupling efficiency limit in perovskite quantum dot light-emitting diodes

“…1c is valid at device level only if individual NCs retain their radiation pattern in the assembled thin films. In practice, many undesirable effects, such as quantum resonance 46 and energy transfer 5 could come into play upon NC assembly. For example, strong face-to-face interactions between CdSe NPLs in the drop-casted film yield the “edge-on” NPL orientation with respect to the substrate, resulting in isotropic radiation pattern 36 .…”

Two-Dimensional Nanoplatelet Superlattices Overcoming Light Outcoupling Efficiency Limit in Perovskite Quantum Dot Light-Emitting Diodes

“…1c is valid at device level only if individual NCs retain their radiation pattern in the assembled thin films. In practice, many undesirable effects, such as quantum resonance 43 and energy transfer 5 could come into play upon NC assembly. For example, strong face-to-face interactions between CdSe NPLs in the drop-casted film yield the "edge-on" NPL orientation with respect to the substrate, resulting in isotropic radiation pattern.…”

Metamaterials‐Based Photoelectric Conversion: From Microwave to Optical Range

“…[5][6][7][8][9][10][11][12][13][14][15] The devices for practical applications should have the advantages of room temperature operation, high responsivity, desirable bandwidth, facile fabrication, low cost, and the like. Many photoelectric devices have been proposed in the past decades by using various structures and materials, such as quantum dots, [16][17][18][19] nanostructured ZnO, [20] optical antennas, [21,22] Schottky barriers, [23][24][25] 2D materials, [26] and electrically small antennas. [27] However, these devices may have drawbacks that limit the practical applications.…”