A Hierarchical Anodic Aluminum Oxide Template

Efficient Photothermal Catalytic Oxidation Enabled by Three-Dimensional Nanochannel Substrates

Photothermal catalysis exhibits promising prospects to overcome the shortcomings of high-energy consumption of traditional thermal catalysis and the low efficiency of photocatalysis. However, there is still a challenge to develop catalysts with outstanding light absorption capability and photothermal conversion efficiency for the degradation of atmospheric pollutants. Herein, we introduced the Co3O4 layer and Pt nanoclusters into the three-dimensional (3D) porous membrane through the atomic layer deposition (ALD) technique, leading to a Pt/Co3O4/AAO monolithic catalyst. The 3D ordered nanochannel structure can significantly enhance the solar absorption capacity through the light-trapping effect. Therefore, the embedded Pt/Co3O4 catalyst can be rapidly heated and the O2 adsorbed on the Pt clusters can be activated to generate sufficient O2- species, exhibiting outstanding activity for the diverse VOCs (toluene, acetone, and formaldehyde) degradation. Optical characterization and simulation calculation confirmed that Pt/Co3O4/AAO exhibited state-of-the-art light absorption and a notable localized surface plasmon resonance (LSPR) effect. In situ diffuse reflectance infrared Fourier transform spectrometry (in situ DRIFTS) studies demonstrated that light irradiation can accelerate the conversion of intermediates during toluene and acetone oxidation, thereby inhibiting byproduct accumulation. Our finding extends the application of AAO's optical properties in photothermal catalytic degradation of air pollutants.

Electron-beam writing of a relaxor ferroelectric polymer for multiplexing information storage and encryption

To meet the strong demand for high-level encryption security, several efforts have been focused on developing new encryption techniques with high density and data security. Herein we employed a template-free electron beam lithography (EBL) technique to write various nanopatterns on poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CTFE)) films and applied it to electron-beam/electric multiplexing memory. Furthermore, electron beams can arbitrarily tailor down the domain structure evolutions and dipole directions, as proved by a combination of AFM-IR and PFM. Finally, our devices could function concurrently as an electron-beam write-only-memory (EB-WOM) and FeRAM, where the information could be encoded with the metastable phase evolutions from the ferroelectric phase to the paraelectric phase and variable bi-level ferroelectric signals. Our systematic study provides an inspiring idea for the design of information encryption devices with high-security requirements in flexible electronic fields.

A microfluidic chip using Au@SiO2 array-based highly SERS-active substrates for ultrasensitive detection of dual cervical cancer-related biomarkers

In this work, a microfluidic chip using Au@SiO₂ array-based highly active SERS substrates was developed for quantitative detection of squamous cell carcinoma antigen (SCCA) and carcinoembryonic antigen (CEA) associated with cervical cancer. The chip consisted of six functional units with pump-free design, enabling parallel detection of multiple samples in an automatic manner without external pumps and improving the portability. Ag nanocubes (AgNCs) were labeled with Raman reporters and coupled with antibodies (labeling) to prepare SERS tags, while the Au nanoparticle-modified SiO₂ microsphere (Au@SiO₂) array was conjugated with antibodies (coating) to generate the highly SERS-active capturing substrate. In the presence of target biomarkers, they were captured by SERS tags and capturing substrate, resulting in the formation of "sandwich" structures which were trapped in the detection chamber. As the immune reaction proceeded, a large number of "hot spots" were generated by the proximity of the Au@SiO₂ array substrate and AgNCs, greatly amplifying SERS signals. With this chip, the limits of detection of the SCCA and CEA levels in human serum were estimated to be as low as 0.45 pg mL^-1 and 0.36 pg mL^-1, respectively. Furthermore, the good selectivity and reproducibility of this chip were confirmed. Finally, clinical serum samples were analyzed by this chip, and the outcomes were consistent with those of enzyme-linked immunosorbent assay (ELISA). Thus, the proposed microfluidic chip can be potentially applied for the clinical diagnosis of cervical cancer.

Au Polyhedron Array with Tunable Crystal Facets by PVP-Assisted Thermodynamic Control and Its Sharp Shape As Well As High-Energy Exposed Planes Co-Boosted SERS Activity

A route is developed for directly growing 2D Au polyhedron arrays with controllable exposed facets of polyhedron by utilizing the substrate-supported 2D Au quasi-spherical nanoparticle arrays as the Au seed arrays, which cannot be realized by traditional lithography. In the reaction system, polyvinyl pyrrolidone (PVP) plays a vital role in guiding the reduced Au atoms and stabilizing the substrate-supported Au seeds. More importantly, by thermodynamic control, PVP as a capping agent can further direct the formation of {111} facets. The key to guarantee the integrity and periodicity of array is a proper reduction of Au ions and low growth rate of crystal. Benefiting from the higher electric field intensity near the sharp vertexes and edges of Au polyhedra and the exposed {110} facets with high energy, the Au polyhedron array with {110} facets encasing polyhedron exhibits good, stable surface enhanced Raman scattering activity toward 4-aminothiophenol among the involved arrays. The proposed fabrication approach tremendously enriches the structural diversity of Au nanoarrays on substrates and greatly overcomes the shortcoming of traditional lithography.

A Self-Ordered Nanostructured Transparent Electrode of High Structural Quality and Corresponding Functional Performance

The preparation of a highly ordered nanostructured transparent electrode based on a combination of nanosphere lithography and anodization is presented. The size of perfectly ordered pore domains is improved by an order of magnitude with respect to the state of the art. The concomitantly reduced density of defect pores increases the fraction of pores that are in good electrical contact with the underlying transparent conductive substrate. This improvement in structural quality translates directly and linearly into an improved performance of energy conversion devices built from such electrodes in a linear manner.