Iron oxide (Fe3O4), polydopamine (PDA), and in particular their composites are examples of the safest nanomaterials for developing multifunctional nanodevices to perform noninvasive tumor diagnosis and therapy. However, the structures and performances of Fe3O4-PDA nanocomposites should be further perfected to enhance the theranostic efficiency. In this work, we demonstrate the fabrication of PDA-capped Fe3O4 (Fe3O4@PDA) superparticles (SPs) employing preassembled Fe3O4 nanoparticles (NPs) as the cores. Owing to the collective effect of preassembled Fe3O4 NPs, the superparamagnetism and photothermal performance of Fe3O4@PDA SPs are greatly enhanced, thus producing nanodevices with improved magnetic resonance imaging (MRI)-guided photothermal efficiency. Systematical studies reveal that the molar extinction coefficient of the as-assembled Fe3O4 SPs is 3 orders of magnitude higher than that of individual Fe3O4 NPs. Also due to the high aggregation degree of Fe3O4 NPs, the T2-weighted MRI contrast is greatly enhanced for the SPs with r2 relaxivity of 230.5 mM(-1) s(-1), which is ∼2.5 times larger than that of individual Fe3O4 NPs. The photothermal stability, physiological stability, and biocompatibility, as well as the photothermal performance of Fe3O4 SPs, are further improved by enveloping with PDA shell.

Photothermal therapy using inorganic nanoparticles (NPs) is a promising technique for the selective treatment of tumor cells because of their capability to convert the absorbed radiation into heat energy. Although anisotropic gold (Au) NPs present an excellent photothermal effect, the poor structural stability during storage and/or upon laser irradiation still limits their practical application as efficient photothermal agents. With the aim of improving the stability, in this work we adopted biocompatible polypyrrole (PPy) as the shell material for coating urchinlike Au NPs. The experimental results indicate that a several nanometer PPy shell is enough to maintain the structural stability of NPs. In comparison to the bare NPs, PPy-coated NPs exhibit improved structural stability toward storage, heat, pH, and laser irradiation. In addition, the thin shell of PPy also enhances the photothermal transduction efficiency (η) of PPy-coated Au NPs, resulting from the absorption of PPy in the red and near-infrared (NIR) regions. For example, the PPy-coated Au NPs with an Au core diameter of 120 nm and a PPy shell of 6.0 nm exhibit an η of 24.0% at 808 nm, which is much higher than that of bare Au NPs (η = 11.0%). As a primary attempt at photothermal therapy, the PPy-coated Au NPs with a 6.0 nm PPy shell exhibit an 80% death rate of Hela cells under 808 nm NIR laser irradiation.

A new and efficient defect post-healing method for carbon-based mesoscopic perovskite solar cells was developed via hydrophobic ligand (TOPO) coordination.

This paper describes the detection of volatile organic compounds (VOCs) using an e-nose type integrated microfabricated sensor array, in which each resonator is coated with different supramolecular monolayers: p-tert-butyl calix[8]arene (Calix[8]arene), 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine (Porphyrin), β-cyclodextrin (β-CD), and cucurbit[8]uril (CB[8]). Supramolecular monolayers fabricated by Langmuir-Blodgett techniques work as specific sensing interface for different VOCs recognition which increase the sensor selectivity. Microfabricated ultrahigh working frequency film bulk acoustic resonator (FBAR) transducers (4.4 GHz) enable their high sensitivity toward monolayer gas sensing which facilitate the analyses of VOCs adsorption isotherms and kinetics. Two affinity constants (K1, K2) are obtained for each VOC, which indicate the gas molecule adsorption happen inside and outside of the supramolecular cavities. Additional kinetic information on adsorption and desorption rate constants (ka, kd) are obtained as well from exponential fitting results. The five parameters, one from the conventional frequency shift signals of mass transducers and the other four from the indirect analyses of monolayer adsorption behaviors, thus enrich the sensing matrix (Δf, K1, K2, ka, kd) which can be used as multiparameter fingerprint patterns for highly selective detection and discrimination of VOCs.

Organic–inorganic hybrid halide perovskite materials have attracted enormous interest in recent years due to their excellent photovoltaic properties, which are strongly limited by their instability. Solar cells based on the inorganic perovskite materials have been developed rapidly and exhibit excellent stability. The crystalline quality and composition of the perovskite layer play the key role in the efficiency of solar cells. Among the various film deposition techniques, pulsed laser deposition has the distinctive advantages of preparation of thin films of high crystalline quality and close duplication of the composition of the targets. In the work, we applied pulsed laser deposition to prepare a CsPbBr3 thin film that displays good stability in a high-humidity environment. Single crystalline CsPbBr3 powders were grown first by a solution method to prepare the target. The CsPbBr3 plasma produced by focused pulsed laser can permeate into the mesoporous TiO2 layer and distribute uniformly inside. The thickness of mesoporous TiO2 and CsPbBr3 layers has a critical influence on device performance. The device with optimization of the layer thickness can achieve the highest power conversion efficiency of 6.3%.

Copper chalcogenide nanomaterials are promising photothermal materials for establishing novel diagnostic and therapeutic methods owing to the low cost but high photothermal transduction efficiency. Further progresses of the correlated technologies greatly depend on the efforts on design and construction of novel nanostructures. In this paper, we demonstrate a facile one-pot route for constructing CuS nanostructures in aqueous media via a spontaneous assembly process. In the presence of polyvinylpyrrolidone (PVP) as the capping agents, a decomposition of Cu(CH3COSH)x precursors is induced by ammonia, which produces hexagonal CuS nanoparticles (NPs) with the diameter around 22 nm. The primary CuS NPs greatly tend to self-assembly into one-dimensional structures, which are triggered by short-range anisotropic dipolar attraction and enforced by long-range isotropic electrostatic repulsion. The further fusion of the assembled NPs generates 480 × 50 nm(2) CuS nanorods. Because the formation of nanorods enhances the internanorod van der Waals attraction, the nanorods finally self-assembly into shuttle-like bundles in micrometer size. In comparison to isolated NPs, the regular CuS assembly structures exhibit improved molar extinction coefficient up to 9.7 × 10(16) cm(-1) M(-1) by shortening the distance of neighboring CuS NPs and therewith generating new electronic structures of the CuS indirect transition. Consequently, better photothermal performance is achieved.

In the present work, we succeeded in alternatively depositing inorganic nanoparticles and functionalized DNA bases onto the water/oil interface from the water and oil bulk phases. The ligands used were functional thymines and adenines. Their thiol and phosphate groups were used to cap inorganic nanoparticles and their thymine and adenine groups to alter the surface functionality of the nanoparticles, thus enabling a layer-by-layer growth fashion of nanoparticles at the interface. The multiple particle ligation rendered the resulting nanoparticle films rather mechanically robust. As results, the freestanding asymmetric bilayer and trilayer films, composed of negatively-charged Au, positively-charged CdTe, and/or organic Ag nanoparticles were constructed; their areas were as large as over several centimetres, depending on the sizes of the containers used. Our work should bring up a novel methodology to generate asymmetric multilayer films of nanoparticles with a defined control of electron or charge across the films.

Photoelectric conversion efficiency of organic-inorganic perovskite solar cells has been rapidly raised and attracted great attention in recent years. The quality of perovskite films is vital for the performance of devices. We used the anti-solvent method to prepare CH3NH3PbI3 thin films by spin coating and dried them at various temperature to transform adduct MAI·PbI2·DMSO into CH3NH3PbI3. We researched in detail on the relationship between surface morphology of MAPbI3 thin films fabricated by the anti-solvent method and various drying temperature. We found that surface roughness and grain size of CH3NH3PbI3 films together increased with increasing drying temperature. The larger grain size could efficiently reduce crystal boundaries which is advantageous for the suppression of photo-induced charge carrier recombination resulting in increase of FF. However, increase of surface roughness resulted in larger contact area at interface which might produce more tarp states and poorer wettability of HTM solution leading in decrease of Jsc. Surface morphology of MAPbI3 layer on the performance of solar cell devices is also an important research issue. By optimizing the drying temperature to 60 o C, the highest efficiency of 14.4% was achieved for the CH3NH3PbI3-based solar cell devices.