The field of chiral inorganic nanostructures is rapidly expanding. It started from the observation of strong circular dichroism during the synthesis of individual nanoparticles (NPs) and their assemblies and expanded to sophisticated synthetic protocols involving nanostructures from metals, semiconductors, ceramics, and nanocarbons. Besides the well-established chirality transfer from bioorganic molecules, other methods to impart handedness to nanoscale matter specific to inorganic materials were discovered, including three-dimentional lithography, multiphoton chirality transfer, polarization effects in nanoscale assemblies, and others. Multiple chiral geometries were observed with characteristic scales from angstroms to microns. Uniquely high values of chiral anisotropy factors that spurred the development of the field and differentiate it from chiral structures studied before, are now well understood; they originate from strong resonances of incident electromagnetic waves with plasmonic and excitonic st...

Chiral Inorganic Nanostructures

In quantum-confined semiconductor nanostructures, electrons exhibit distinctive behavior compared with that in bulk solids. This enables the design of materials with tunable chemical, physical, electrical, and optical properties. Zero-dimensional semiconductor quantum dots (QDs) offer strong light absorption and bright narrowband emission across the visible and infrared wavelengths and have been engineered to exhibit optical gain and lasing. These properties are of interest for imaging, solar energy harvesting, displays, and communications. Here, we offer an overview of advances in the synthesis and understanding of QD nanomaterials, with a focus on colloidal QDs, and discuss their prospects in technologies such as displays and lighting, lasers, sensing, electronics, solar energy conversion, photocatalysis, and quantum information.

Semiconductor quantum dots: Technological progress and future challenges

Throughout the 19th and 20th century, chirality has mostly been associated with chemistry. However, while chirality can be very useful for understanding molecules, molecules are not well suited for understanding chirality. Indeed, the size of atoms, the length of molecular bonds and the orientations of orbitals cannot be varied at will. It is therefore difficult to study the emergence and evolution of chirality in molecules, as a function of geometrical parameters. By contrast, chiral metal nanostructures offer an unprecedented flexibility of design. Modern nanofabrication allows chiral metal nanoparticles to tune the geometric and optical chirality parameters, which are key for properties such as negative refractive index and superchiral light. Chiral meta/nano-materials are promising for numerous technological applications, such as chiral molecular sensing, separation and synthesis, super-resolution imaging, nanorobotics, and ultra-thin broadband optical components for chiral light. This review covers some of the fundamentals and highlights recent trends. We begin by discussing linear chiroptical effects. We then survey the design of modern chiral materials. Next, the emergence and use of chirality parameters are summarized. In the following part, we cover the properties of nonlinear chiroptical materials. Finally, in the conclusion section, we point out current limitations and future directions of development.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adom.201700182

Chirality and Chiroptical Effects in Metal Nanostructures: Fundamentals and Current Trends

Metal Halide Perovskites in Quantum Dot Solar Cells: Progress and Prospects

Plasmon-coupled circular dichroism has emerged as a promising approach for ultrasensitive detection of biomolecular conformations through coupling between molecular chirality and surface plasmons. Chiral nanoparticle assemblies without chiral molecules present also have large optical activities. We apply single-particle circular differential scattering spectroscopy coupled with electron imaging and simulations to identify both structural chirality of plasmonic aggregates and plasmon-coupled circular dichroism induced by chiral proteins. We establish that both chiral aggregates and just a few proteins in interparticle gaps of achiral assemblies are responsible for the ensemble signal, but single nanoparticles do not contribute. We furthermore find that the protein plays two roles: It transfers chirality to both chiral and achiral plasmonic substrates, and it is also responsible for the chiral three-dimensional assembly of nanorods. Understanding these underlying factors paves the way toward sensing the chirality of single biomolecules.

Unraveling the origin of chirality from plasmonic nanoparticle-protein complexes

Circular dichroism spectroscopy is essential for structural characterization of proteins and chiral nanomaterials. Chiral structures from plasmonic materials have extraordinary strong circular dichroism effects compared to their molecular counterparts. While being extensively investigated, the comprehensive account of circular dichroism effects consistent with other plasmonic phenomena is still missing. Here we investigated the circular differential scattering of a simple chiral plasmonic system, a twisted side-by-side Au nanorod dimer, using single-particle circular dichroism spectroscopy complimented with electromagnetic simulations. This approach enabled us to quantify the effects of structural symmetry breaking, namely, size-mismatch between the constituent Au nanorods and large twist angles on the resulting circular differential scattering spectrum. Our results demonstrate that, if only scattering is considered as measured by dark-field spectroscopy, a homodimer of Au nanorods with similar sizes prod...

/pdf/circular-differential-scattering-of-single-chiral-self-yov45gcqtl.pdf

Circular Differential Scattering of Single Chiral Self-Assembled Gold Nanorod Dimers

Any new solar photovoltaic (PV) technology must reach low production costs to compete with today's market-leading crystalline silicon and commercial thin-film PV technologies Colloidal quantum dots (QDs) could open up new applications by enabling lightweight and flexible PV modules However, the cost of synthesizing nanocrystals at the large scale needed for PV module production has not previously been investigated Based on our experience with commercial QD scale-up, we develop a Monte Carlo model to analyze the cost of synthesizing lead sulfide and metal halide perovskite QDs using 8 different reported synthetic methods We also analyze the cost of solution-phase ligand exchange for preparing deposition-ready PbS QD inks, as well as the manufacturing cost for roll-to-roll solution-processed PV modules using these materials We find that present QD synthesis costs are prohibitively high for PV applications, with median costs of 11 to 59 $ per g for PbS QDs (015 to 084 $ per W for a 20% efficient cell) and 73 $ per g for CsPbI3 QDs (074 $ per W) QD ink preparation adds 63 $ per g (009 $ per W) In total, QD materials contribute up to 55% of the total module cost, making even roll-to-roll-processed QDPV modules significantly more expensive than silicon PV modules These results suggest that the development of new low-cost synthetic methods is critically important for the commercial relevance of QD photovoltaics Using our cost model, we identify strategies for reducing synthetic cost and propose a cost target of 5 $ per g to move QD solar cells closer to commercial viability

/pdf/synthesis-cost-dictates-the-commercial-viability-of-lead-5bshnykyt9.pdf

Synthesis cost dictates the commercial viability of lead sulfide and perovskite quantum dot photovoltaics

Any new solar photovoltaic (PV) technology must reach low production costs to compete with today's market-leading crystalline silicon and commercial thin-film PV technologies. Colloidal quantum dots (QDs) could open up new applications by enabling lightweight and flexible PV modules. However, the cost of synthesizing nanocrystals at the large scale needed for PV module production has not previously been investigated. Based on our experience with commercial QD scale-up, we develop a Monte Carlo model to analyze the cost of synthesizing lead sulfide and metal halide perovskite QDs using 8 different reported synthetic methods. We also analyze the cost of solution-phase ligand exchange for preparing deposition-ready PbS QD inks, as well as the manufacturing cost for roll-to-roll solution-processed PV modules using these materials. We find that present QD synthesis costs are prohibitively high for PV applications, with median costs of 11 to 59 $ per g for PbS QDs (0.15 to 0.84 $ per W for a 20% efficient cell) and 73 $ per g for CsPbI3 QDs (0.74 $ per W). QD ink preparation adds 6.3 $ per g (0.09 $ per W). In total, QD materials contribute up to 55% of the total module cost, making even roll-to-roll-processed QDPV modules significantly more expensive than silicon PV modules. These results suggest that the development of new low-cost synthetic methods is critically important for the commercial relevance of QD photovoltaics. Using our cost model, we identify strategies for reducing synthetic cost and propose a cost target of 5 $ per g to move QD solar cells closer to commercial viability.

Assessing the Regulatory Requirements of Lead-Based Perovskite Photovoltaics

Efficient, Flexible, and Ultra-Lightweight Inverted PbS Quantum Dots Solar Cells on All-CVD-Growth of Parylene/Graphene/oCVD PEDOT Substrate with High Power-per-Weight

Nicole Moody

Papers

Circular Differential Scattering of Single Chiral Self-Assembled Gold Nanorod Dimers

Synthesis cost dictates the commercial viability of lead sulfide and perovskite quantum dot photovoltaics

Synthesis cost dictates the commercial viability of lead sulfide and perovskite quantum dot photovoltaics

Assessing the Regulatory Requirements of Lead-Based Perovskite Photovoltaics

Efficient, Flexible, and Ultra-Lightweight Inverted PbS Quantum Dots Solar Cells on All-CVD-Growth of Parylene/Graphene/oCVD PEDOT Substrate with High Power-per-Weight