Chiral 3D structures through multi-dimensional transfer printing of multilayer quantum dot patterns.

Three-dimensional optical nanostructures have garnered significant interest in photonics due to their extraordinary capabilities to manipulate the amplitude, phase, and polarization states of light. However, achieving complex three-dimensional optical nanostructures with bottom-up fabrication has remained challenging, despite its nanoscale precision and cost-effectiveness, mainly due to inherent limitations in structural controllability. Here, we report the optical characteristics of intricate two- and three-dimensional nanoarchitectures made of colloidal quantum dots fabricated with multi-dimensional transfer printing.

Ultrafine Filteration of Metal Catalysts Enables Fabrication of Silicon Nanowires with Diameter Approaching a Unit Cell Size.

Advanced functionalities of silicon nanowires are size-dependent and downscaling of the nanostructure often leads to higher device performances. Single-crystal silicon nanowires with diameters approaching a single unit cell are fabricated using membrane-filtrated catalyst assisted chemical etching. Atomically filtrated gold is used as uniform pattern to direct anisotropic etching of dense silicon nanowire arrays.

Ultrahigh-resolution quantum dot patterning for advanced optoelectronic devices.

Quantum dots have attracted significant scientific interest owing to their optoelectronic properties, which are distinct from their bulk counterparts. In order to fully utilize quantum dots for next generation devices with advanced functionalities, it is important to fabricate quantum dot colloids into dry patterns with desired feature sizes and shapes with respect to target applications. In this review, recent progress in ultrahigh-resolution quantum dot patterning technologies will be discussed, with emphasis on the characteristic advantages as well as the limitations of diverse technologies.

Noninvasive and Direct Patterning of High-Resolution Full-Color Quantum Dot Arrays by Programmed Microwetting.

Although the commercialization of electroluminescent quantum-dot (QD) displays essentially demands multicolor patterning of QDs with sufficient scalability and uniformity, the implementation of QD patterning in a light-emitting diode device is highly challenging, mainly due to the innate vulnerability of QDs and charge-transport layers. Here, we introduce a noninvasive surface-wetting approach for patterning full-color QD arrays on a photoprogrammed hole-transport layer (HTL). To achieve noninvasiveness of QD patterning, surface-specific modification of HTLs was performed without degrading their performance.

Polychromatic Quantum Dot Array to Compose a Community Signal Ensemble for Multiplexed miRNA Detection.

We herein describe a polychromatic quantum dot array (PQDA) to compose a community signal ensemble enabling accurate and precise quantification of miRNAs in a multiplexed manner. Advanced multicomponent ultrahigh-resolution patterning technique achieved by capsulation-assisted transfer printing following self-assembly-based poly(methyl methacrylate) (PMMA) patterning is utilized to manufacture the PQDA, which is designed to discharge a target miRNAs-specific set of fluorescent quantum dots (QDs) through the activity of duplex-specific nuclease (DSN). On the basis of the community signal ensemble produced by the discharged QD profiles, target miRNAs are very specifically identified down to a femtomolar level (1.

Microcellular sensing media with ternary transparency states for fast and intuitive identification of unknown liquids.

Rapid, accurate, and intuitive detection of unknown liquids is greatly important for various fields such as food and drink safety, management of chemical hazards, manufacturing process monitoring, and so on. Here, we demonstrate a highly responsive and selective transparency-switching medium for on-site, visual identification of various liquids. The light scattering–based sensing medium, which is designed to be composed of polymeric interphase voids and hollow nanoparticles, provides an extremely large transmittance window (>95%) with outstanding selectivity and versatility.

Template Dissolution Interfacial Patterning of Single Colloids for Nanoelectrochemistry and Nanosensing.

Deterministic positioning and assembly of colloidal nanoparticles (NPs) onto substrates is a core requirement and a promising alternative to top-down lithography to create functional nanostructures and nanodevices with intriguing optical, electrical, and catalytic features. Capillary-assisted particle assembly (CAPA) has emerged as an attractive technique to this end, as it allows controlled and selective assembly of a wide variety of NPs onto predefined topographical templates using capillary forces. One critical issue with CAPA, however, lies in its final printing step, where high printing yields are possible only with the use of an adhesive polymer film.

Thermodynamic-driven polychromatic quantum dot patterning for light-emitting diodes beyond eye-limiting resolution.

The next-generation wearable near-eye displays inevitably require extremely high pixel density due to significant decrease in the viewing distance. For such denser and smaller pixel arrays, the emissive material must exhibit wider colour gamut so that each of the vast pixels maintains the colour accuracy. Electroluminescent quantum dot light-emitting diodes are promising candidates for such application owing to their highly saturated colour gamuts and other excellent optoelectronic properties.

Order-of-Magnitude, Broadband-Enhanced Light Emission from Quantum Dots Assembled in Multiscale Phase-Separated Block Copolymers.

Achieving high emission efficiency in solid-state quantum dots (QDs) is an essential requirement for high-performance QD optoelectronics. However, most QD films suffer from insufficient excitation and light extraction efficiencies, along with nonradiative energy transfer between closely adjacent QDs. Herein, we suggest a highly effective strategy to enhance the photoluminescence (PL) of QD composite films through an assembly of QDs and poly(styrene--4-vinylpyridine)) (PS--P4VP) block copolymer (BCP).

Topographically-designed triboelectric nanogenerator via block copolymer self-assembly.

Herein, we report a facile and robust route to nanoscale tunable triboelectric energy harvesters realized by the formation of highly functional and controllable nanostructures via block copolymer (BCP) self-assembly. Our strategy is based on the incorporation of various silica nanostructures derived from the self-assembly of BCPs to enhance the characteristics of triboelectric nanogenerators (TENGs) by modulating the contact-surface area and the frictional force. Our simulation data also confirm that the nanoarchitectured morphologies are effective for triboelectric generation.