Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

The Journal of Physical Chemistry Letters

Hybrid halide perovskites are now superstar materials leading the field of low-cost thin film photovoltaics technologies. Following the surge for more efficient and stable 3D bulk alloys, multilayered halide perovskites and colloidal perovskite nanostructures appeared in 2016 as viable alternative solutions to this challenge, largely exceeding the original proof of concept made in 2009 and 2014, respectively. This triggered renewed interest in lower-dimensional hybrid halide perovskites and at the same time increasingly more numerous and differentiated applications. The present paper is a review of the past and present literature on both colloidal nanostructures and multilayered compounds, emphasizing that availability of accurate structural information is of dramatic importance to reach a fair understanding of quantum and dielectric confinement effects. Layered halide perovskites occupy a special place in the history of halide perovskites, with a large number of seminal papers in the 1980s and 1990s. In ...

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Quantum and Dielectric Confinement Effects in Lower-Dimensional Hybrid Perovskite Semiconductors.

Nanolasers generate coherent light at the nanoscale. In the past decade, they have attracted intense interest, because they are more compact, faster and more power-efficient than conventional lasers. Thanks to these capabilities, nanolasers are now an emergent tool for a variety of practical applications. In this Review, we explain the intrinsic merits of nanolasers and assess recent progress on their applications, particularly for optical interconnects, near-field spectroscopy and sensing, optical probing for biological systems and far-field beam synthesis through near-field eigenmode engineering. We highlight the scientific and engineering challenges that remain for forging nanolasers into powerful tools for nanoscience and nanotechnology.

Applications of nanolasers.

Perovskite photodetectors (PPDs), which combine the advantages of perovskite semiconductor materials with superior optical and electronic properties and solution-processed manufacturing, have emerged as a new class of revolutionary optoelectronic devices with potential for various practical applications. Encouraged by the development of various solution-synthesis and film-deposition techniques for controlling the morphology and composition of perovskite materials with interesting optoelectronic properties, increasing research attention is focused on the development of high performance PPDs. In this review, the recent progress on emerging PPDs is comprehensively summarized from the perspective of device physics and materials science. The strategies for extending the spectral response range of PPDs and improving the performance of devices are investigated. Furthermore, the methods for realizing narrowband photodetectors are also discussed, where filter-free and self-filter narrowband PPDs are achieved based on the concept of charge collection narrowing. Meanwhile, the promising future directions in this research field are proposed and discussed, including multifunctional PPDs, perovskite–organic hybrid photodetectors, flexible and transparent PPDs, self-powered PPDs, and photodetector systems and arrays. This review provides valuable insights into the current status of highly sensitive PPDs and will spur the design of new structures and devices to further enhance their photo-detection performances and meet the need of versatility in practical application.

Recent progress on highly sensitive perovskite photodetectors

The achievement of structural color has shown advantages in large-gamut, high-saturation, high-brightness, and high-resolution. While a large number of plasmonic/dielectric nanostructures have been developed for structural color, the previous approaches fail to match all the above criterion simultaneously. Herein we utilize the Si metasurface to demonstrate an all-in-one solution for structural color. Due to the intrinsic material loss, the conventional Si metasurfaces only have a broadband reflection and a small gamut of 78% of sRGB. Once they are combined with a refractive index matching layer, the reflection bandwidth and the background reflection are both reduced, improving the brightness and the color purity significantly. Consequently, the experimentally demonstrated gamut has been increased to around 181.8% of sRGB, 135.6% of Adobe RGB, and 97.2% of Rec.2020. Meanwhile, high refractive index of silicon preserves the distinct color in a pixel with 2 × 2 array of nanodisks, giving a diffraction-limit resolution. Here, the authors fabricate a metasurface with high brightness and large gamut structured colors by combining a silicon metasurface with a refractive index matching layer. The experimentally demonstrated gamut is 181.8% of sRGB, 135.6% of Adobe RGB, and 97.2% of Rec.2020.

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All-dielectric metasurface for high-performance structural color.

Recent Advances in Perovskite Micro- and Nanolasers

Highly reproducible organometallic-halide-perovskite-based devices are fabricated by a manufacturing process, which is demonstrated. Various shapes that are hard to synthesize directly are fabricated, and many unique properties are achieved.The fabrication procedure is utilized to create a photodetector and the detection sensitivity is significantly improved. The results will bring revolutionary advancement to the future of lead-halide-perovskite-based optoelectronic devices.

Highly Reproducible Organometallic Halide Perovskite Microdevices based on Top-Down Lithography.

On-chip integrated mode-division multiplexing (MDM) is an emerging technique for large-capacity data communications. In the past few years, while several configurations have been developed to realize on-chip MDM circuits, their practical applications are significantly hindered by the large footprint and inter-mode cross talk. Most importantly, the high-speed MDM signal transmission in an arbitrarily routed circuit is still absent. Herein, we demonstrate the MDM circuits based on digitized meta-structures which have extremely compact footprints. 112 Gbit/s signals encoded on each mode are arbitrarily routed through the circuits consisting of many sharp bends and compact crossings with a bit error rate under forward error correction limit. This will significantly improve the integration density and benefit various on-chip multimode optical systems. On-chip mode-division multiplexing has many challenges including crosstalk, losses, and footprint.  Here the authors use a nanohole metastructure to create multiplexed bends and crossings for photonic data communications circuit routing with high density that combats these challenges.

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Arbitrarily routed mode-division multiplexed photonic circuits for dense integration.

Discontinuously reinforced titanium matrix composites (DRTMCs), as one of the most important metal matrix composites (MMCs), are expected to exhibit high strength, elastic modulus, high-temperature endurability, wear resistance, isotropic property, and formability. Recent innovative research shows that tailoring the reinforcement network distribution totally differently from the conventional homogeneous distribution can not only improve the strengthening effect but also resolve the dilemma of DRTMCs with poor tensile ductility. Based on the network architecture, multiscale architecture, for example, two-scale network and laminate-network microstructure can further inspire superior strength, creep, and oxidation resistance at elevated temperatures. Herein, the most recent developments, which include the design, fabrication, microstructure, high-temperature performance, strengthening mechanisms, and future research opportunities for DRTMCs with multiscale architecture, are captured. In this regard, the service temperature can be increased by 200 °C, and the creep rupture time by 59-fold compared with those of conventional titanium alloys, which can meet the urgent demands of lightweight nickel-based structural materials and potentially replace nickel base superalloys at 600-800 °C to reduce weight by 45%. In fact, multiscale architecture design strategy will also favorably open a new era in the research of extensive metallic materials for improved performances.

Shuai Wang

Papers

All-dielectric metasurface for high-performance structural color.

Recent Advances in Perovskite Micro- and Nanolasers

Highly Reproducible Organometallic Halide Perovskite Microdevices based on Top-Down Lithography.

Arbitrarily routed mode-division multiplexed photonic circuits for dense integration.

Multiscale Architecture and Superior High-Temperature Performance of Discontinuously Reinforced Titanium Matrix Composites