Colloidal Quantum Dots: Synthesis, Composition, Structure, and Emerging Optoelectronic Applications

Abstract

In recent decades, quantum dots (QDs) with tunable bandgap, large absorption coefficient, high quantum yield, multiexciton effect, and easy solution processing have unparalleled advantages in photoelectric conversion. Optoelectronic devices based on QDs of different composition have made great progress. However, there is still a lack of reviews on comparing the optoelectronic application level of semiconductor quantum dots (SQDs), perovskite quantum dots (PQDs), and carbon quantum dots (CDs), and also rarely providing a comprehensive summary of photocatalysis. First, this review almost completely summarizes advantages and disadvantages of common synthesis methods for QDs, especially pointing out the importance of optimization strategies for preparing high‐quality QDs such as ligand engineering, ion exchange, and purification separation. Then, compositions of SQD, PQD, CD, and corresponding optoelectronic properties are introduced, respectively. Next, the strengths and weaknesses of the four QDs structures are compared in detail. Finally, the flourishing development in various optoelectronic applications is separately demonstrated, and development degree of SQDs, PQDs, and CDs is compared to discover the most suitable application scenarios for each. On these bases, bottlenecks and opportunities are also put forwarded, hoping to stimulate more breakthroughs in this field.

An ultra-sensitive colloidal quantum dot infrared photodiode exceeding 100 000% external quantum efficiency via photomultiplication

“…Colloidal quantum dots (CQDs) are promising next-generation materials for optoelectronic devices because of their lowtemperature solution-based processability [13][14][15] coupled with high adsorption and crystalline robustness, which allow them to be directly deposited on silicon readout integrated circuits. 16,17 In particular, lead chalcogenide (PbE) (PbS and PbSe) CQDs have been used as IR absorbing materials owing to their widely programmable absorption range from visible to short wavelength IR coupled with their high intrinsic absorption coefficient (410 4 cm À1 ) and high electron and hole mobility (410 À1 cm V À1 s À1 ).…”

Engineering and Controlling Perovskite Emissions via Optical Quasi‐Bound‐States‐in‐the‐Continuum

“…[9,10] However, the nature of such bottom-up methods inevitably leads to some degree of nonuniformity in the particle morphology, which can result in line broadening and inconsistent emission wavelengths due to the quantum confinement effect. [11] Furthermore, after the chemical reaction is completed, the luminescence properties of the perovskite are fixed and cannot be fine-tuned in situ. Such drawbacks are detrimental in applications that require the refined tuning of emissions at specific wavelengths, such as light-emitting diodes (LEDs), [12][13][14][15] photodetectors, [16][17][18] single-photon sources, [19] and lasers.…”

Size- and Shape-Dependent Separation of Multinary Quantum Dots with Plasmonic Thin-Layer Chromatography

“…Semiconductor quantum dots (QDs) with particle sizes of typically less than 10 nm exhibit unique electrical and optical properties that are different from those of bulk materials. − These properties, which are influenced by size and chemical composition, are of great interest for applications in photovoltaics, photocatalysis, biomarkers, and light-emitting devices (LEDs). − In recent years, multinary QDs composed of environmentally friendly group I–III–VI semiconductors, such as AgInS 2 and CuInS 2 , and their solid solutions with ZnS have attracted increasing attention as safer alternatives to conventional binary QDs containing highly toxic heavy metal elements such as CdSe, CdTe, and PbS. − These I–III–VI-based QDs exhibit unique physicochemical properties, which are dependent not only on size and chemical composition but also on shape. For example, rod-shaped QDs exhibited a higher photocatalytic activity than that of their spherical counterparts for H 2 evolution. − Therefore, precise control of the morphology of QDs is a prerequisite for improving their performance.…”