Self‐Assembly of Semiconductor Quantum Dots using Organic Templates

Abstract

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are regarded as brightly photoluminescent nanomaterials possessing outstanding photophysical properties, such as high photodurability and tunable absorption and emission wavelengths. Therefore, QDs have great potential for a wide range of applications, such as in photoluminescent materials, biosensors and photovoltaic devices. Since the development of synthetic methods for accessing high‐quality QDs with uniform morphology and size, various types of QDs have been designed and synthesized, and their photophysical properties dispersed in solutions and at the single QD level have been reported in detail. In contrast to dispersed QDs, the photophysical properties of assembled QDs have not been revealed, although the structures of the self‐assemblies are closely related to the device performance of the solid‐state QDs. Therefore, creating and controlling the self‐assembly of QDs into well‐defined nanostructures is crucial but remains challenging. In this Minireview, we discuss the notable examples of assembled QDs such as dimers, trimers and extended QD assemblies achieved using organic templates. This Minireview should facilitate future advancements in materials science related to the assembled QDs.

A Highly Ordered Quantum Dot Supramolecular Assembly Exhibiting Photoinduced Emission Enhancement

“…On the other hand, understanding the physical properties derived from inter‐QD interactions observed in the solid condition of QDs is quite important for the development of QD‐based materials science [20–23] . Although QD structures could be formed on substrates by the evaporation of solvents, such an assembly method gives rise to the formation of inhomogeneous and ill‐defined structures, and furthermore, the formation of assembled QDs in solution is quite difficult [24] . Recently, we proposed a strategy to form assembled QDs assisted by the self‐assembly of organic dyes [25] .…”

Coupling in quantum dot molecular hetero-assemblies

“…In the last few years, a great scientific effort has been made to deeply understand the coupling mechanisms among colloidal quantum dots (QDs) interacting with each other when spaced at nanometric and sub-nanometric distances. [1][2][3][4][5][6][7][8][9] The elucidation of the interaction mechanisms among the QDs both in solution and in solid-state can open the opportunity to realize highly efficient charge transfer systems for optoelectronic devices and take a jump towards new fancy applications like quantum computing, [2,3,10] spintronic devices, [11] biosensors, [12,13] solar cells [14,15] and chiralinduced spin selectivity effect. [16] In these applications, the surface chemistry of the QDs, often controlled by the ligands, [17] plays a key role and an adequate understanding of the type of coupling involved that takes also in consideration the role of the organic capping layer is needed.…”

Real-time observation of nucleation and growth of Au on CdSe quantum dot templates

“…Size dependence of semiconducting QDs with tunable band-gap affect their optical properties. A sharp size distribution and a long-range order of QDs is beneficial, because it leads to a more uniform emission spectrum 11 . The photoluminescence can be further enhanced and the emission spectrum be broadened by combining these semiconductor QD with metals, such as Au or Ag, having plasmonic properties.…”