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Glioblastoma (GBM) is a refractory disease that has a highly infiltrative characteristic. Over the past decade, GBM perivascular niche (PVN) has been described as a route of dissemination. Here, we investigated that trailed membrane structures, namely retraction fibers (RFs), are formed by perivascular extracellular matrix (ECM) proteins. By using the anatomical GBM database, we validated that the ECM-related genes were highly expressed in the cells within the PVN where fibronectin (FN) induced RF formation. By disrupting candidates of FN-binding integrins, integrin α5β1 was identified as the main regulator of RF formation. De novo RFs were produced at the trailing edge, and focal adhesions were actively localized in RFs, indicating that adhesive force makes RFs remain at the bottom surface. Furthermore, we observed that GBM cells more frequently migrated along the residual RFs formed by preceding cells in microfluidic channels in comparison to those in the channels without RFs, suggesting that the infiltrative characteristics GBM could be attributed to RFs formed by the preceding cells in concert with chemoattractant cues. Altogether, we demonstrated that shedding membrane structures of GBM cells are maintained by FN-integrin α5β1 interaction and promoted their motility .

In this article, the capabilities of soft and hard X-ray techniques, including X-ray absorption (XAS), soft X-ray emission spectroscopy (XES), resonant inelastic soft X-ray scattering (RIXS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), and their application to solid-state hydrogen storage materials are presented. These characterization tools are indispensable for interrogating hydrogen storage materials at the relevant length scales of fundamental interest, which range from the micron scale to nanometer dimensions. Since nanostructuring is now well established as an avenue to improve the thermodynamics and kinetics of hydrogen release and uptake, due to properties such as reduced mean free paths of transport and increased surface-to-volume ratio, it becomes of critical importance to explicitly identify structure-property relationships on the nanometer scale. X-ray diffraction and spectroscopy are effective tools for probing size-, shape-, and structure-dependent material properties at the nanoscale. This article also discusses the recent development of in-situ soft X-ray spectroscopy cells, which enable investigation of critical solid/liquid or solid/gas interfaces under more practical conditions. These unique tools are providing a window into the thermodynamics and kinetics of hydrogenation and dehydrogenation reactions and informing a quantitative understanding of the fundamental energetics of hydrogen storage processes at the microscopic level. In particular, in-situ soft X-ray spectroscopies can be utilized to probe the formation of intermediate species, byproducts, as well as the changes in morphology and effect of additives, which all can greatly affect the hydrogen storage capacity, kinetics, thermodynamics, and reversibility. A few examples using soft X-ray spectroscopies to study these materials are discussed to demonstrate how these powerful characterization tools could be helpful to further understand the hydrogen storage systems.

The energetic sulfide vapor process on colloidal indium arsenide (InAs) quantum dots (QDs) for integrated optoelectronic devices is demonstrated. X‐ray photoemission spectroscopy supports the presence of sulfur on QD surface, which increases the air stability, and ultraviolet photoemission spectroscopy and field‐effect transistor analysis confirm n‐type charge transport of corresponding QD films with higher electron mobilities. Photoconductivity of the same devices in near‐infrared wavelength shows gate bias‐dependent recombination of photogenerated carriers, coming from charge accumulation and depletion transition of QD channels. The synergetic approach of the vapor process on colloidal QD solids opens a promising opportunity for scalable and complementary metal‐oxide semiconductor‐compatible optoelectronic devices.

Silver dimetal chalcogenide (Ag-V-VI2 ) ternary quantum dots (QDs) are emerging lead-free materials for optoelectronic devices due to their NIR band gaps, large absorption coefficients, and superior electronic properties. However, thin film-based devices of the ternary QDs still lag behind due to the lack of understanding of the surface chemistry, compared to that of lead chalcogenide QDs even with the same crystal structure. Herein the surface ligand interactions of AgSbS2 QDs, synthesized with 1-dodecanethiol used as a stabilizer, are studied. For nonpolar (1 0 0) surfaces, it is suggested that the thiolate ligands are associated with the crystal lattices, thus preventing surface oxidation by protecting sulfur after air-exposure, as confirmed through optical and surface chemical analysis. Otherwise, silver rich (1 1 1) surfaces are passivated by thiolate ligands, allowing ligand exchange processes for the conductive films. This in-depth investigation of the surface chemistry of ternary QDs will prompt the performance enhancement of their optoelectronic devices.

Quantum dots (QDs) are emerging photovoltaic materials that display exclusive characteristics that can be adjusted through modification of their size and surface chemistry. However, designing a QD-based optoelectronic device requires specialized approaches compared with designing conventional bulk-based solar cells. In this paper, design considerations for QD thin-film solar cells are introduced from two different viewpoints: optics and electrics. The confined energy level of QDs contributes to the adjustment of their band alignment, enabling their absorption characteristics to be adapted to a specific device purpose. However, the materials selected for this energy adjustment can increase the light loss induced by interface reflection. Thus, management of the light path is important for optical QD solar cell design, whereas surface modification is a crucial issue for the electrical design of QD solar cells. QD thin-film solar cell architectures are fabricated as a heterojunction today, and ligand exchange provides suitable doping states and enhanced carrier transfer for the junction. Lastly, the stability issues and methods on QD thin-film solar cells are surveyed. Through these strategies, a QD solar cell study can provide valuable insights for future-oriented solar cell technology.

A new configuration of a plasmonic quantum dots solar structure is proposed. Gold-silver core-shell metal nanoparticles (Au@Ag NCs) are incorporated into the TiO2 layer (Au@Ag NCs-HL) of PbS-based solar cells. The TiO2 layer enables the Au@Ag NCs to have broad plasmonic responses and the external quantum efficiency and absorption of the plasmonic devices are significantly enhanced. The electrical performance of the solar cells is also improved.

The absorption and photoluminescence (PL) properties of silicon quantum dots (QDs) are greatly influenced by their size and surface chemistry. Herein, we examined the optical properties of three Si QDs with increasing σ-π conjugation length: octyl-, (trimethylsilyl)vinyl-, and 2-phenylvinyl-capped Si QDs. The PL photon energy obtained from as-prepared samples decreased by 0.1-0.3 eV, while the PL excitation (PLE) extended from 360 nm (octyl-capped Si QDs) to 400 nm (2-phenylvinyl-capped Si QDs). A vibrational PL feature was observed in all samples with an energy separation of about 0.192±0.013 eV, which was explained based on electron-phonon coupling. After soft oxidization through drying, all samples showed blue PL with maxima at approximately 410 nm. A similar high-energy peak was observed with the bare Si QD sample. The changes in the optical properties of Si QDs were mainly explained by the formation of additional states arising from the strong σ-π conjugation and QD oxidation.

Chemically synthesized InP nanocrystals (NCs) are drawing a large interest as a potentially less toxic alternative to CdSe-based nanocrystals. With a bulk band gap of 1.35 eV and an exciton Bohr radius of ∼10 nm the emission wavelength of InP NCs can in principle be tuned throughout the whole visible and near-infrared range by changing their size. Furthermore, a few works reported fluorescence quantum yields exceeding 70% after overcoating the core NCs with appropriate shell materials. Therefore, InP NCs are very promising for use in lighting and display applications. On the other hand, a number of challenges remain to be addressed in order to progress from isolated research results to robust and reproducible synthesis methods for high quality InP NCs. First of all, the size distribution of the as-synthesized NCs needs to be reduced, which directly translates into more narrow emission line widths. Next, reliable protocols are required for achieving a given emission wavelength at high reaction yield and fo...

A novel self-charging platform is proposed using colloidal-quantum-dot (CQD) photovoltaics (PVs) via the near-infrared (NIR) band for low-power electronics. Low-bandgap CQDs can convert invisible NIR light sources to electrical energy more efficiently than wider spectra because of reduced thermalization loss. This energy-conversion strategy via NIR photons ensures an enhanced photostability of the CQD devices. Furthermore, the NIR wireless charging system can be concealed using various colored and NIR-transparent fabric or films, providing aesthetic freedom. Finally, an NIR-driven wireless charging system is demonstrated for a wearable healthcare bracelet by integrating a CQD PVs receiver with a flexible lithium-ion battery and entirely embedding them into a flexible strap, enabling permanent self-charging without detachment.

Colloidal quantum dots (CQDs) are promising light harvesting materials for realization of solution processible, highly efficient multipurpose photovoltaics (PVs). Here, PbS CQD solar cells are reported with improved certified power conversion efficiency performance of 10.4% by simply controlling protic solvents (alcohols) in ligand exchange process. With shorter chain alcohols, the mobility of charge carriers is an order-of-magnitude improved due to the enhanced interparticle coupling; on the other hand, excessive removal of passivating ligands by very protic solvent, methanol (MeOH) induced undesirable traps on CQD surface. Consequently, it has been found that high performance CQD PVs require a solvent engineering for balance between native leaving ligands with incoming ligands during ligand exchange process for well-controlled surfaces of CQDs and enhanced carrier concentration of conductive CQD films.