KJN

Porous silicon nanoparticles are loaded with bpV(HOpic), a tropomyosin‐related kinase receptor type B RNA aptamer, or nerve growth factor using three distinct loading chemistries. They are incorporated into aligned poly(lactic‐co‐ glycolic acid) nanofibers using an airbrush, and the nanofiber hybrids release their payloads over varying timescales. The three released payloads maintain their bioactivity as shown by enhanced neurite extension of dorsal root ganglion explants cultured on the hybrid nanofiber scaffolds.

Abstract

Scaffolds made from biocompatible polymers provide physical cues to direct the extension of neurites and to encourage repair of damaged nerves. The inclusion of neurotrophic payloads in these scaffolds can substantially enhance regrowth and repair processes. However, many promising neurotrophic candidates are excluded from this approach due to incompatibilities with the polymer or with the polymer processing conditions. This work provides one solution to this problem by incorporating porous silicon nanoparticles (pSiNPs) that are preloaded with the therapeutic into a polymer scaffold during fabrication. The nanoparticle‐drug‐polymer hybrids are prepared in the form of oriented poly(lactic‐co ‐glycolic acid) nanofiber scaffolds. Three different therapeutic payloads are tested: bpV(HOpic), a small molecule inhibitor of phosphatase and tensin homolog (PTEN); an RNA aptamer specific to tropomyosin‐related kinase receptor type B (TrkB); and the protein nerve growth factor (NGF). Each therapeutic is loaded using a loading chemistry that is optimized to slow the rate of release of these water‐soluble payloads. The drug‐loaded pSiNP‐nanofiber hybrids release approximately half of their TrkB aptamer, bpV(HOpic), or NGF payload in 2, 10, and >40 days, respectively. The nanofiber hybrids increase neurite extension relative to drug‐free control nanofibers in a dorsal root ganglion explant assay.

Recent progress in computing devices based on carbon nanotubes is reviewed, with an emphasis on the relationship between chirality enrichment and electronic functionality. A range of chirality‐dependent electronic applications is explored including monolithic logic‐memory, optoelectronic integrated circuits, neuromorphic devices, and enantiomer‐recognition sensors. By identifying remaining challenges and opportunities, a roadmap for next‐generation carbon nanotube computing is provided.

Abstract

For the past half century, silicon has served as the primary material platform for integrated circuit technology. However, the recent proliferation of nontraditional electronics, such as wearables, embedded systems, and low‐power portable devices, has led to increasingly complex mechanical and electrical performance requirements. Among emerging electronic materials, single‐walled carbon nanotubes (SWCNTs) are promising candidates for next‐generation computing as a result of their superlative electrical, optical, and mechanical properties. Moreover, their chirality‐dependent properties enable a wide range of emerging electronic applications including sub‐10 nm complementary field‐effect transistors, optoelectronic integrated circuits, and enantiomer‐recognition sensors. Here, recent progress in SWCNT‐based computing devices is reviewed, with an emphasis on the relationship between chirality enrichment and electronic functionality. In particular, after highlighting chirality‐dependent SWCNT properties and chirality enrichment methods, the range of computing applications that have been demonstrated using chirality‐enriched SWCNTs are summarized. By identifying remaining challenges and opportunities, this work provides a roadmap for next‐generation SWCNT‐based computing.

Personalized medicine is transforming how diseases are managed in the clinic. At the same time, biomimetic nanotechnology offers many advantages that can be leveraged toward the design of more effective medical interventions. Recent developments in biomimetic nanovaccines against cancer and bacterial infections are discussed, with a specific emphasis on potential avenues for personalization.

Abstract

While traditional approaches for disease management in the era of modern medicine have saved countless lives and enhanced patient well‐being, it is clear that there is significant room to improve upon the current status quo. For infectious diseases, the steady rise of antibiotic resistance has resulted in super pathogens that do not respond to most approved drugs. In the field of cancer treatment, the idea of a cure‐all silver bullet has long been abandoned. As a result of the challenges facing current treatment and prevention paradigms in the clinic, there is an increasing push for personalized therapeutics, where plans for medical care are established on a patient‐by‐patient basis. Along these lines, vaccines, both against bacteria and tumors, are a clinical modality that could benefit significantly from personalization. Effective vaccination strategies could help to address many challenging disease conditions, but current vaccines are limited by factors such as a lack of potency and antigenic breadth. Recently, researchers have turned toward the use of biomimetic nanotechnology as a means of addressing these hurdles. Recent progress in the development of biomimetic nanovaccines for antibacterial and anticancer applications is discussed, with an emphasis on their potential for personalized medicine.

Can you easily recognize spoiled fish? In article number https://doi.org/10.1002/adma.2019070641907064, Sung Yeon Hwang, Jeyoung Park, Dongyeop X. Oh, and co‐workers present innovative time–temperature indicators that show whether fresh foods are diverged from a cold‐supply chain. A self‐healing nanofiber mat enables highly sensitive, tamper‐proof, damage‐tolerant, and self‐responsive changes in transparency by the flow of thermodynamic free energy.

A structure and function integrated printing method is proposed for preparing 3D facade‐based photodetectors between predesigned gold electrodes. Due to the enlarged cross section in the 3D asymmetric rectangular structure, the facade photodetectors with branched geometry achieve the omnidirectional angle detection. This strategy provides a general guidance toward novel 3D nanostructured photoelectric devices.

Abstract

Integration of photovoltaic materials directly into 3D light–matter resonance architectures can extend their functionality beyond traditional optoelectronics. Semiconductor structures at subwavelength scale naturally possess optical resonances, which provides the possibility to manipulate light–matter interactions. In this work, a structure and function integrated printing method to remodel 2D film to 3D self‐standing facade between predesigned gold electrodes, realizing the advancement of structure and function from 2D to 3D, is demonstrated. Due to the enlarged cross section in the 3D asymmetric rectangular structure, the facade photodetectors possess sensitive light–matter interaction. The single 3D facade photodetectors can measure the incident angle of light in 3D space with a 10° angular resolution. The resonance interaction of the incident light at different illumination angles and the 3D subwavelength photosensitive facade is analyzed by the simulated light flow in the facade. The 3D facade structure enhances the manipulation of the light–matter interaction and extends metasurface nanophotonics to a wider range of materials. The monitoring of dynamic variation is achieved in a single facade photodetector. Together with the flexibility of structure and function integrated printing strategy, three and four branched photodetectors extend the angle detection to omnidirectional ranges, which will be significant for the development of 3D angle‐sensing devices.

A centimeter‐scale, visible wavelength light‐emitting display is demonstrated utilizing a tungsten disulfide monolayer synthesized via chemical vapor deposition. Operated in the transient mode, the device exhibits bright red emission from an emission layer measuring 0.7 nm in thickness. This work highlights the potential use of monolayer semiconductors in ultrathin displays, taking advantage of their high luminescence quantum yields.

Abstract

Monolayer 2D transition metal dichalcogenides (TMDCs) have shown great promise for optoelectronic applications due to their direct bandgaps and unique physical properties. In particular, they can possess photoluminescence quantum yields (PL QY) approaching unity at the ultimate thickness limit, making their application in light‐emitting devices highly promising. Here, large‐area WS₂ grown via chemical vapor deposition is synthesized and characterized for visible (red) light‐emitting devices. Detail optical characterization of the synthesized films is performed, which show peak PL QY as high as 12%. Electrically pumped emission from the synthetic WS₂ is achieved utilizing a transient‐mode electroluminescence device structure, which consists of a single metal–semiconductor contact and alternating gate fields to achieve bipolar emission. Utilizing this aforementioned structure, a centimeter‐scale (≈0.5 cm²) visible (640 nm) display is demonstrated, fabricated using TMDCs to showcase the potential of this material system for display applications.

Incorporation of various single amino acids into the structure of Cu₂O semiconductor leads to continuous variations in its band gap. A strong blueshift in the band gap of up to 18% is achieved via the bioinspired route.

Abstract

Semiconductors have numerous applications in both science and technology. Several methods have been developed to engineer their band gap, which is one of the most important parameters of semiconductors. Here, it is shown that the incorporation of various amino acids into the crystal lattice of copper (I) oxide, akin to the way living organisms incorporate organic macromolecules into minerals during biomineralization, leads to significant shrinkage in the volume of the host unit cell and a strong blueshift in the band gap of up to ≈18%. In examining the potential location of the bio‐organic molecules within the inorganic host's lattice, a very good fit between the proposed model of incorporation and experimental findings is found. The bioinspired phenomenon of band gap widening is thought to be attributable to the void‐induced quantum confinement effect, even though observed in micrometer‐sized crystals. This hypothesis is supported by developing a tight‐binding model that is found to fit well with the experimental data. The outcome of this research could profoundly impact the fields of light‐emitting and spin‐based devices as well as opens up a new bioinspired route to tune the band gap of semiconductors.

Stable and efficient mixed tin–lead (Sn–Pb) perovskite solar cells (PSCs) are demonstrated by defect passivation with ultrathin layered perovskites. The passivation layer provides defect passivation both at the film surface and the grain boundaries, without blocking the carrier transport. The devices exhibit a certified power conversion efficiency (PCE) of 18.95%, and a 200 h diurnal operating stability.

Abstract

The development of narrow‐bandgap (E _g ≈ 1.2 eV) mixed tin–lead (Sn–Pb) halide perovskites enables all‐perovskite tandem solar cells. Whereas pure‐lead halide perovskite solar cells (PSCs) have advanced simultaneously in efficiency and stability, achieving this crucial combination remains a challenge in Sn–Pb PSCs. Here, Sn–Pb perovskite grains are anchored with ultrathin layered perovskites to overcome the efficiency‐stability tradeoff. Defect passivation is achieved both on the perovskite film surface and at grain boundaries, an approach implemented by directly introducing phenethylammonium ligands in the antisolvent. This improves device operational stability and also avoids the excess formation of layered perovskites that would otherwise hinder charge transport. Sn–Pb PSCs with fill factors of 79% and a certified power conversion efficiency (PCE) of 18.95% are reported—among the highest for Sn–Pb PSCs. Using this approach, a 200‐fold enhancement in device operating lifetime is achieved relative to the nonpassivated Sn–Pb PSCs under full AM1.5G illumination, and a 200 h diurnal operating time without efficiency drop is achieved under filtered AM1.5G illumination.

A generic strategy is demonstrated to eliminate the van der Waals (vdW) gap in a broad class of heterostructures. The vdW gap is bridged via strong orbital hybridization, resulting in reduced interface transfer resistance. The photon‐triggered on/off ratio and photoresponse time of the bridged heterostructures are several orders of magnitude higher than that of common vdW heterostructures.

Abstract

Van der Waals (vdW) heterostructures exhibit excellent optoelectronic properties and novel functionalities. However, their applicability is impeded due to the common issue of the tunneling barrier, which arises from the vdW gap; this significantly increases the injection resistance of the photoexcited carriers. Herein, a generic strategy is demonstrated to eliminate the vdW gap in a broad class of heterostructures. It is observed that the vdW gap in the interface is bridged via strong orbital hybridization between the interface dangling bonds of nonlayered chalcogenide semiconductors and the artificially induced vacancies of transition metal chalcogenides (TMDCs). The photoresponse times of bridged PbS/ReS₂, PbS/MoSe₂, and PbS/MoS₂ are ≈30, 51, and 43 µs, respectively. The photon‐triggered on/off ratio of the bridged PbS/MoS₂, ZnSe/MoS₂, and ZnTe/MoS₂ heterostructures exceed 10⁶, 10⁵, and 10⁵, respectively. These are several orders of magnitude higher than common vdW heterostructures. The findings obtained in this study present a versatile strategy for overcoming the performance limitations of vdW heterostructures.