Recent Advances in Two-Dimensional Quantum Dots and Their Applications

Abstract

Two-dimensional quantum dots have received a lot of attention in recent years due to their fascinating properties and widespread applications in sensors, batteries, white light-emitting diodes, photodetectors, phototransistors, etc. Atomically thin two-dimensional quantum dots derived from graphene, layered transition metal dichalcogenide, and phosphorene have sparked researchers’ interest with their unique optical and electronic properties, such as a tunable energy bandgap, efficient electronic transport, and semiconducting characteristics. In this review, we provide in-depth analysis of the characteristics of two-dimensional quantum dots materials, their synthesis methods, and opportunities and challenges for novel device applications. This analysis will serve as a tipping point for learning about the recent breakthroughs in two-dimensional quantum dots and motivate more scientists and engineers to grasp two-dimensional quantum dots materials by incorporating them into a variety of electrical and optical fields.

Resistive Switching Accompanied by Negative Differential Resistance in Cysteine-Functionalized WS2 Quantum Dots toward Nonvolatile Memory Devices

“…Figure S4 displays the AFM image of cysteine-functionalized WS 2 QDs, indicating that the thickness was ∼3.5–4 nm. The QDs investigated are ∼4–5 layers because the reported thickness of a single-layer WS 2 is about 0.77 nm. , Figure b shows the PL spectrum of cysteine-functionalized WS 2 QDs, similar to those of previous reports. − The PL could originate from the recombination due to excitons and/or localized defect states . The linewidth of PL in cysteine-functionalized WS 2 QDs is broad, which could be attributed to a combination of cascade PL signals due to synergetic effects of defects and size distribution.…”

Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

“…Top-down approaches applying strategies such as oxidative/intercalative delamination, − , ultrasonic waves, ,, ball milling, ,, and electric spark are scalable but often lead to poor control of size distributions and the number of stacked layers . Alternatively, bottom-up strategies such as CVD are more common to prepare high-quality single layers but are limited by their narrow scope, which is limited to certain crystalline phases and elemental compositions. , A limited number of solution-phase synthetic routes involving the condensation of molecular units are more flexible in achieving versatile compositions, subnanometer dimensions (quantum dots, , nanoribbons, , etc. ), and diverse functional-group inclusions in NMs , but require further advancements in strategies and scalability .…”

Colorimetric Sensor Based on Ag-Fe NTs for H2S Sensing

“…Different ratios of ligands on the surface of NTs also determine the distance between particles, which, in turn, controls the plasmonic coupling of the Ag x -Fe 2– x NTs and the color of the solution. − Without using any instrument, it is easy for the naked eye to distinguish the color change. As shown in Figure a, Ag 0.6 -Fe 1.4 NTs react with the increasing concentrations of H 2 S, changing the color of the solution to yellow and finally brown; further, the plasmonic peak originally at ∼346 and ∼376 nm gradually decreases in intensity and eventually disappears, indicating that Ag x -Fe 2– x NTs are gradually etched by H 2 S and eventually no longer have a triangular structure (Supporting Information Figure S1).…”