Optical Properties, Synthesis, and Potential Applications of Cu-Based Ternary or Quaternary Anisotropic Quantum Dots, Polytypic Nanocrystals, and Core/Shell Heterostructures

Abstract

This review summaries the optical properties, recent progress in synthesis, and a range of applications of luminescent Cu-based ternary or quaternary quantum dots (QDs). We first present the unique optical properties of the Cu-based multicomponent QDs, regarding their emission mechanism, high photoluminescent quantum yields (PLQYs), size-dependent bandgap, composition-dependent bandgap, broad emission range, large Stokes’ shift, and long photoluminescent (PL) lifetimes. Huge progress has taken place in this area over the past years, via detailed experimenting and modelling, giving a much more complete understanding of these nanomaterials and enabling the means to control and therefore take full advantage of their important properties. We then fully explore the techniques to prepare the various types of Cu-based ternary or quaternary QDs (including anisotropic nanocrystals (NCs), polytypic NCs, and spherical, nanorod and tetrapod core/shell heterostructures) are introduced in subsequent sections. To date, various strategies have been employed to understand and control the QDs distinct and new morphologies, with the recent development of Cu-based nanorod and tetrapod structure synthesis highlighted. Next, we summarize a series of applications of these luminescent Cu-based anisotropic and core/shell heterostructures, covering luminescent solar concentrators (LSCs), bioimaging and light emitting diodes (LEDs). Finally, we provide perspectives on the overall current status, challenges, and future directions in this field. The confluence of advances in the synthesis, properties, and applications of these Cu-based QDs presents an important opportunity to a wide-range of fields and this piece gives the reader the knowledge to grasp these exciting developments.

Giant Stokes Shifts in AgInS2 Nanocrystals with Trapped Charge Carriers

“…In the last years, ternary I-III-VI (I = Cu, Ag; III = In, Sn, Ga, Al and VI = S, Se, Te) nanocrystals have received significant attention due to their compositional and structural versatility and unique optical properties. [1][2][3][4][5] These materials are promising candidates for the eco-friendly replacement of broadly studied II-VI and IV-VI binary nanocrystals containing inherently toxic elements such as Cd or Pb 5,6 . Particularly interesting examples of Cd-free ternary nanocrystals are CuInS 2 and AgInS 2 showing strong defect-state photoluminescence in the visible and near-infrared regions with comparatively high photoluminescence quantum yields exceeding 90%.…”

Synthesis of emission tunable AgInS2/ZnS quantum dots and application for light emitting diodes

“…Both sample heterogeneities including size polydispersity and random positioning of the emitting center are considered to be account for the broad emission of PL. It is still remained unclear whether the observed wide FWMH is an intrinsic optical property [13,14,34]. During the process of QD solution transferring to QD film, solvent evaporation and ligand detachment caused by spinning, annealing or other handling will increase the dot concentration and lead to the dot aggregation.…”

“…In recent years, I-III-VI QDs, such as CuInS 2 (CIS) and AgInS 2 (AIS), being free of heavy metals, have attracted substantial attention. Generally, I-III-VI QDs exhibit large Stokes' shift and wide full-width at half-maximum (FWHM), which enable them to be excellent color-converters for fabricating photoluminescent white LEDs with high color render index (CRI) [13,14]. They also have been reported to be used to assemble electroluminescent LEDs.…”

Design Principle of Reactive Components for Dimethacrylate‐Terminated Quantum Dots: Preserved Photoluminescent Quantum Yield, Excellent Pattern Uniformity, and Suppression of Aggregation in the Matrix

“…Semiconductor quantum dots (e.g., II‐VI, IV‐VI QDs)1–3 attract a lot of attention due to their excellent optical properties (e.g., narrow emission, high luminous efficiency) and the ease of adjustment of solution processing4–10 based on surface chemistry 11–14. As a result, applications for cost‐effective wet‐based manufacturing systems as well as various optoelectronic devices, for example, color converting thin‐films and printable inks for advanced liquid crystal displays,4,15,16 micro‐light emitting diodes,17 luminescent solar concentrators,18,19 and smart lighting systems (e.g., visible light communication),20–23,15 are being actively developed.…”

“…QD photopolymerizable composite systems consist of various reactive components (e.g., reactive monomers including oligomers, any types of additives, diluents), and processability/film properties (e.g., adhesion, hardness and softness, and chemical resistances) depend on the physicochemical properties and stoichiometric adjustments of the components. However, such additives are often incompatible with typical QDs1–3 and surface modified QDs, resulting in degradation of optical properties and severe aggregation in the matrix. Therefore, the need for a simple component system that enables direct patterning is steadily increasing.…”