A method is presented that allows for the first time the preparation of highly defined polymer brush coatings on the wafer-scale under ambient conditions (room temperature, exposure to air) from a broad variety of monomers. The discovered high oxygen-tolerance of the surface-initiated Cu(0)-mediated controlled radical polymerization (SI-CuCRP) yields entire wafers homogeneously covered by a polymer brush of linear, high molar mass polymers with narrow dispersities (Đ = 1.1) at extremely high grafting densities (≈1 chain per nm 2 ). The low-tech and air tolerant method requires only ≲4 mL reaction solution containing a monomer and a ligand between two facing substrates. Thus, the SI-CuCRP is scalable to any surface area with minimal costs and minimal equipment. Despite the simplicity of the method, the high endgroup fidelity of SI-CuCRP is demonstrated by the preparation of a tetrablock copolymer brush which is the first example of a higher order block copolymer brush prepared by any surface-initiated polymerization. Finally, we present a new facile lithographic technique, the copper plate proximity printing (CP 3 ), which relies on the proximity of the bulk copper surface to the initiator-bearing substrate. The CP 3 is resist-and development-free and transfers the copper plate profile (of a copper coin) directly into an image composed of a 3D polymer brush. † Electronic supplementary information (ESI) available. See

Nature has created an efficient sterilization model, i.e., the in situ bacterial capture and killing process via bacteriophages. The bacteriophage is a virus with a unique spiny tail foot; in general, it can capture bacteria and subsequently release nucleic acid to achieve replication and kill bacteria. We define this two-steps process as the localized "capture and killing" (LCK) action. Therefore, it is believed that this bioinspired LCK action may provide massive possibilities for developing efficient disinfection strategies as alternatives to conventional clinical antibiotic treatments. Two concepts must be carefully designed and integrated to construct the bionic nanosystem with LCK action. i) Developing the spiky nanostructures to enhance the interactions between nanomaterials and pathogenic bacteria; [11,12] meanwhile, the spiky structure must be mesoporous to load and release bactericidal substances. [13] ii) Second, developing an efficient and robust bactericidal system without using any antibiotics. [14-18] Compared to many traditional bactericidal molecules, antibacterial strategies based on reactive oxygen species (ROS) have been intensively studied. [19] Due to its short life cycle, ROS can only cause irreversible damage to substances immediately around it. This spatially confined activity helps to develop targeted applications as well as guarantee excellent biocompatibility during usage. [20,21] Moreover, the molecular weight of ROS is very Besides the pandemic caused by the coronavirus outbreak, many other pathogenic microbes also pose a devastating threat to human health, for instance, pathogenic bacteria. Due to the lack of broad-spectrum antibiotics, it is urgent to develop nonantibiotic strategies to fight bacteria. Herein, inspired by the localized "capture and killing" action of bacteriophages, a virus-like peroxidase-mimic (V-POD-M) is synthesized for efficient bacterial capture (mesoporous spiky structures) and synergistic catalytic sterilization (metalorganic-framework-derived catalytic core). Experimental and theoretical calculations show that the active compound, MoO 3 , can serve as a peroxocomplex-intermediate to reduce the free energy for catalyzing H 2 O 2 , which mainly benefits the generation of •OH radicals. The unique virus-like spikes endow the V-POD-M with fast bacterial capture and killing abilities (nearly 100% at 16 µg mL-1). Furthermore, the in vivo experiments show that V-POD-M possesses similar disinfection treatment and wound skin recovery efficiencies to vancomycin. It is suggested that this inexpensive, durable, and highly reactive oxygen species (ROS) catalytic active V-POD-M provides a promising broad-spectrum therapy for nonantibiotic disinfection. The global pandemic caused by the outbreak of coronavirus has aroused tremendous attention across broad scientific communities. Besides the coronavirus pandemic, many other pathogenic microbes also pose a devastating threat to human health. For instance, pathogenic bacteria have infected millions of people and caused almos...

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Second-order Raman modes correlate with the electrical properties of reduced graphene oxide measured at the nanoscale by atomic force microscopy.

It is believed that plasmon-excited electrons from Ag and Au nanostructures can induce photochemical reactions. However, the influence of heat generated by nanoparticle (NP) hotspots during light irradiation was not systematically studied yet. To evaluate the role of plasmonic heating, we performed a surface-enhanced Raman spectroscopy study of the photocatalytic conversion of 4-nitrobenzenthiol to 4-aminobenzenthiol by metal NPs with different compositions and shapes having localized surface plasmon resonances (LSPRs) spanning the whole visible range. Our collective results based on temperature-dependent studies and multiwavelength analyses show that contrary to the previous reports, the photocatalytic reaction is not only determined by the excitation of LSPRs or by the NP material (Ag or Au) but also drastically dependent on the plasmon-induced heating. This work has strong implications for the development and engineering of novel plasmonic and photonic applications where the role of localized temperature must be considered.

Tip-enhanced Raman spectroscopy (TERS) has been rapidly improved over the past decade and opened up opportunities to study phonon properties of materials at the nanometer scale. In this Letter, we report on TERS of an ultrathin MoS flake on a nanostructured Au on silicon surface forming a two-dimensional (2D) crystal/plasmonic heterostructure. Au nanostructures (shaped in triangles) are prepared by nanosphere lithography, and then MoS is mechanically exfoliated on top of them. The TERS spectra acquired under resonance conditions at 638 nm excitation wavelength evidence strain changes spatially localized to regions as small as 25 nm in TERS imaging. We observe the highest Raman intensity enhancement for MoS on top of Au nanotriangles due to the strong electromagnetic confinement between the tip and a single triangle. Our results enable us to determine the local strain in MoS induced during heterostructure formation. The maximum frequency shift of E mode is determined to be (4.2 ± 0.8) cm, corresponding to 1.4% of biaxial strain induced in the MoS layer. We find that the regions of maximum local strain correspond to the regions of maximum topographic curvature as extracted from atomic force microscopy measurements. This tip-enhanced Raman spectroscopy study allows us to determine the built-in strain that arises when 2D materials interact with other nanostructures.

Two-dimensional (2D) van derWaals semiconductors have been the subject of intense research due to their low dimensionality and tunable optoelectronic properties. However, the stability of these materials in air is one of the important issues that needs to be clarified, especially for technological applications. Here the time evolution of GaSe oxidation from monolayer to bulk is investigated by Raman spectroscopy, photoluminescence emission, and x-ray photoelectron spectroscopy. The Raman spectroscopy study reveals that GaSe monolayers become oxidized almost immediately after exposure to air. However, the oxidation is a self-limiting process taking roughly 5 h to penetrate up to 3 layers of GaSe. After oxidation, GaSe single-layers decompose into amorphous Se which has a strong Raman cross section under red excitation. The present study provides a clear picture of the stability of GaSe in air and will guide future research of GaSe from single-to few-layers for the appropriate development of novel technological applications for this promising 2D material.

Gallium selenide (GaSe) is a layered semiconductor and a well-known nonlinear optical crystal. The discovery of graphene has created a new vast research field focusing on two-dimensional materials. We report on the nonlinear optical properties of few-layer GaSe using multiphoton microscopy. Both second- and third-harmonic generation from few-layer GaSe flakes were observed. Unexpectedly, even the peak at the wavelength of 390 nm, corresponding to the fourth-harmonic generation or the sum frequency generation from third-harmonic generation and pump light, was detected during the spectral measurements in thin GaSe flakes.