Excellent Near-infrared Absorption Research Articles

Metal-Determined Explosive Characteristics of M(NO3)2(1-AT)x of Thermal and Laser Ignition (M2+ = Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+; x = 2 or 3).

Optical and thermal ignition are two common pathways to initiate the explosion of primary explosives, where laser ignition is a more reliable and safer initiation method. Caused by the current-applied laser igniter with the wavelength of 1064 or 915 nm, the energetic complexes with strong absorption in the near-infrared (NIR) region are possibly applied as laser-ignited explosives. Recently, [Cu(NO3)2(1-AT)3] complex has been synthesized with excellent NIR absorption properties, where 1-amino-5H-tetrazole (1-AT) has been proved to be a promising laser-ignited energetic ligand. To confirm the structure-thermal/optical explosive characteristics, based on the structure of synthesized [Cu(NO3)2(1-AT)3], the commonly used transition-metal cations (M2+ = Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+) have been selected to construct the series of complexes of M(NO3)2(1-AT)x (x = 2 or 3) theoretically. Car-Parrinello molecular dynamics (CPMD) method has been applied to unveil the role of center metals in the initiation and growth pathways. Time-dependent density functional theory (TD-DFT) method is used to explore their charge-transfer (CT) characteristics. The optical characteristic of the metal complex is mainly determined by the behaviors of the 3d electrons of center metals in excitation, where the activity of β-d electrons is an important factor to affect the NIR characteristic of complexes.

Mechanism of Self-Oxidative Copolymerization and its Application with Polydopamine-pyrrole Nano-copolymers.

Currently, the copolymer of dopamine (DA) and pyrrole (PY) via chemical and electrochemical oxidation usually requires additional oxidants, and lacks flexibility in regulating the size and morphology, thereby limiting the broad applications of DA-PY copolymer in biomedicine. Herein, the semiquinone radicals produced by the self-oxidation of DA is ingeniously utilized as the oxidant to initiate the following copolymerization with PY, and a series of quinone-rich polydopamine-pyrrole copolymers (PDAm -nPY) with significantly enhanced absorption in near-infrared (NIR) region without any additional oxidant assistance is obtained. Moreover, the morphology and size of PDAm -nPY can be regulated by changing the concentration of DA and PY, thereby optimizing nanoscale PDA0.05 -0.15PY particles (≈ 150nm) with excellent NIR absorption and surface modification activity are successfully synthesized. Such PDA0.05 -0.15PY particles show effective photoacoustic (PA) imaging and photothermal therapy (PTT) against 4T1 tumors in vivo. Furthermore, other catechol derivatives canalso copolymerize with PY under the same conditions. This work by fully utilizing the semiquinone radical active intermediates produced through the self-oxidation of DA reduces the dependence on external oxidants in the synthesis of composite materials and predigests the preparation procedure, which provides a novel, simple, and green strategy for the synthesis of other newly catechol-based functional copolymers.

Photothermally boosted Fenton-like activity of copper sulfide toward the catalytic degradation of 4-chlorophenol

Fenton/Fenton-like reactions have promising implications in biomedicine and environment-related remediation. However, their applications are still limited because of incomplete light utilization, low energy-conversion efficiency, and inefficient H2O2 utilization. Herein, near infrared (NIR) light absorbance and photothermal conversion were utilized for H2O2 activation to achieve 4-chlorophenol (4-CP) elimination from water by using a typical doped copper sulfide (Cu2−xS) semiconductor developed via a hydrothermal method. The obtained CuS is not only an attractive Fenton-like agent but also exhibits efficient photothermal conversion performance in the NIR spectral range, which broadens the use of the solar spectrum and is beneficial to the photothermal-enhanced Fenton-like degradation process. As expected, by irradiating with an NIR laser (1064 nm), the CuS exhibits excellent NIR absorption capacity and produces hyperpyrexia above 50 ℃. Importantly, the photothermal effects of the CuS nanosheets significantly enhanced the yield of the Fenton-like reaction by accelerating the generation and diffusion of free radicals (h+, •O2-, 1O2, and especially •OH), which enabled the key mechanism for pollutant degradation. In addition, CuS nanosheets exhibited good stability during the degradation of 4-CP, with low metal-ion leakage and a broad pH range applicability, and the degradation rate was hardly affected by laser power, catalyst concentration, and the presence of metal ions. These results demonstrate the strong potential of the photothermal-enhanced Fenton-like effect in pollutant degradation and propose a promising strategy for environmental remediation with the effective utilization of solar energy.

DNA Damage Inducer Mitoxantrone Amplifies Synergistic Mild-Photothermal Chemotherapy for TNBC via Decreasing Heat Shock Protein 70 Expression.

Patients with triple-negative breast cancer (TNBC) have the worst clinical outcomes when compared to other subtypes of breast cancer. Nanotechnology-assisted photothermal therapy (PTT) opens new opportunities for precise cancer treatment. However, thermoresistance caused by PTT, as well as uncertainty in the physiological metabolism of existing phototherapeutic nanoformulations, severely limit their clinical applications. Herein, based on the clinically chemotherapeutic drug mitoxantrone (MTO), a multifunctional nanoplatform (MTO-micelles) is developed to realize mutually synergistic mild-photothermal chemotherapy. MTO with excellent near-infrared absorption (≈669nm) can function not only as a chemotherapeutic agent but also as a photothermal transduction agent with elevated photothermal conversion efficacy (ƞ = 54.62%). MTO-micelles can accumulate at the tumor site through the enhanced permeability and retention effect. Following local near-infrared irradiation, mild hyperthermia (<50°C) assists MTO in binding tumor cell DNA, resulting in chemotherapeutic sensitization. In addition, downregulation of heat shock protein 70 (HSP70) expression due to enhanced DNA damage can in turn weaken tumor thermoresistance, boosting the efficacy of mild PTT. Both in vitro and in vivo studies indicate that MTO-micelles possess excellent synergetic tumor inhibition effects. Therefore, the mild-photothermal chemotherapy strategy based on MTO-micelles has a promising prospect in the clinical transformation of TNBC treatment.

Thermochromic Ni(II) Organometallics With High Optical Transparency and Low Phase-Transition Temperature for Energy-Saving Smart Windows.

Thermochromic smart windows with rational modulation in indoor temperature and brightness draw considerable interest in reducing building energy consumption, which remains a huge challenge to meet the comfortable responsive temperature and the wide transmittance modulation range from visible to near-infrared (NIR) light for their practical application. Herein, a novel thermochromic Ni(II) organometallic of [(C2 H5 )2 NH2 ]2 NiCl4 for smart windows is rationally designed and synthesized via an inexpensive mechanochemistry method, which processes a low phase-transition temperature of 46.3 °C for the reversible color evolution from transparent to blue with a tunable visible transmittance from 90.5% to 72.1%. Furthermore, cesium tungsten bronze (CWO) and antimony tin oxide (ATO) with excellent NIR absorption in 750-1500 and 1500-2600nm are introduced in the [(C2 H5 )2 NH2 ]2 NiCl4 -based smart windows, realizing a broadband sunlight modulation of a 27% visible light modulation and more than 90% of NIR shielding ability. Impressively, these smart windows demonstrate stable and reversible thermochromic cycles at room temperature. Compared with the conventional windows in the field tests, these smart windows can significantly reduce the indoor temperature by 16.1 °C, which is promising for next-generation energy-saving buildings.

Effects of crystal structure and morphology on the electrochromic properties of CsxWO3

Smart windows have been used to reduce indoor energy consumption by utilizing materials with excellent near-infrared absorption properties, among which cesium tungsten bronze CsxWO3 is one of the widely used materials. However, the stability of CsxWO3 during applications is a very challenging problem. The electrochromic technology can be used to solve it. Here, nano CsxWO3 with space group P63/mcm has been synthesized to study the effects of the crystal structure and morphology on the electrochromic properties by tailoring the reaction condition during the solvothermal process. The sizes of hexagonal and trigonal channels in WO6 framework change with the reaction condition of samples and reach to their maximum values at the highest Cs content. The cluster-shaped grains uniformly distribute in the sample with the highest Cs content. Both of the transmittance modulation range and coloration efficiency of this sample are about several times than those of other samples. The large-size channels in WO6 framework and rod-like cluster morphology facilitate the enhancement of electrochromic properties.

Near‐Infrared Light‐Activatable Bismuth‐Based Nanomaterials for Antibacterial and Antitumor Treatment

AbstractThe treatment of diseases through precision phototherapy has attracted growing interest during the last decade. Remarkably, biocompatible bismuth‐based nanomaterials can be effectively activated by near‐infrared (NIR) light to fight bacterial infections and tumors. In addition, bismuth‐containing nanostructures are easy to be synthesized and exhibit excellent NIR absorption, ideal photothermal conversion, and X‐ray sensitivity for diagnosis and treatment. This review outlined the recent development of bismuth‐based nanomaterials in NIR phototherapy. The three most commonly used NIR‐responsive bismuth‐based nanomaterials including pristine bismuth nanomaterials, bismuth‐based compound nanomaterials, and bismuth‐based composite nanomaterials are exemplified. Furthermore, their photothermal and photodynamic therapy mechanisms, antibacterial, and antitumor applications are summarized. In addition, their NIR phototherapy enhancement strategies are also highlighted. Finally, the key issues and future directions of bismuth‐based nanomaterial phototherapy systems are discussed in detail. It is believed that the emerging NIR light‐activatable bismuth‐based nanomaterials can realize the actual antibacterial and antitumor via unremitting efforts of scientific researchers in the near future.

NIR-driven PtCu-alloy nanocages via photothermal enhanced fenton catalytic degradation of pollutant dyes under neutral pH

In this work, near-infrared (NIR) light driven concave octopod PtCu alloy nanocages (OPtCu-NCs) were fabricated and first developed as photothermal synergetic Fenton catalyst for degradation of pollutant dyes. Moreover, by irradiating with NIR laser (808 nm), the obtained OPtCu-NCs exhibit excellent NIR absorption capacity and thus produce hyperpyrexia over 50 °C. Concomitantly, by the photothermal effect, the OPtCu-NCs nanocatalysts was used for elimination of organic dyes such as Methylene blue (MB) and Rhodamine B (RhB). The NIR-driven photothermal degradation mechanism under NIR irradiation can be attributed to the Fenton-like catalytic performance of Cu ions, then -NC- and/or C-C bonds in the molecular skeleton were fractured and electrons were donated intensively. As confirmed by a typical radical trapping experiment, electrons trigger the formation of miscellaneous reactive species (O2-, HO2, especially •OH) subsequently. Moreover, the photothermal Fenton-catalytic activity of the as-prepared OPtCu-NCs had maintained at 93.15% (for MB) and 91.87% (for RhB) after ten circulating degradation processes. All acquired results reveal that the OPtCu-NCs have the potential applied value in dyestuff-wastewater treatment under neutral pH.

Filament Development for Laser Assisted FFF 3D Printing

The aim of this paper was to develop filaments which can be used for laser assisted fused filament fabrication (FFF) 3D printing in order to increase the inter-layer bonding strength of the printed part. The filaments were developed from the most commonly used filament materials, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) with the addition of different polymer additives. After performing near infrared (NIR) absorption tests, graphite was selected for further development as it possesses excellent NIR absorption capabilities whilst resulting in consistent filaments’ diameter and being economically viable. A conventional FFF 3D printer was initially used to test the printability of the developed filaments. Afterwards, a fiber couple laser diode was integrated within the printing head to heat up the previously extruded layer. The produced filaments were used to 3D print specimens for shear and tensile testing. With the laser heating, an increase of 14.5% in the elastic modulus and an increase of 27.8% in the tensile strength of the printed parts were noticed. This showed that adding additives into filament materials for localized laser heating is an effective method of increasing the inter-layer bonding, and therefore, the overall strength and durability of FFF 3D printed parts.

Folic Acid Functionalized Carbon Dot/Polypyrrole Nanoparticles for Specific Bioimaging and Photothermal Therapy.

Polypyrrole nanoparticles (PPy-NPs) with excellent near-infrared absorption are commonly used as photothermal therapy (PTT) agents; however, PTT using PPy-NPs has a limitation in that it is difficult to maximize their therapeutic effect because of the lack of specific targeting. In this study, to overcome the difficulty of targeting, folic acid functionalized carbon dots (FA-CDs) with bright green fluorescence properties were combined with carboxylated PPy-NPs via the EDC/NHS coupling reaction to yield a PTT imaging agent. The synthesized FA-CD/PPy-NPs with excellent photostability performed folate receptor (FR) positive HeLa cancer cell imaging by green fluorescence signals of FA-CDs and exhibited high cell viability (above 90%) even at 500 μg/mL. The viability of HeLa cells incubated with 200 μg/mL FA-CD/PPy-NPs was dramatically decreased to 25.02 ± 1.85% by NIR laser irradiation, through photothermal therapeutic effects of FA-CD/PPy-NPs with high photothermal conversion efficiency (η = 40.80 ± 1.54%). The cancer cell death by FA-CD/PPy-NPs was confirmed by fluorescence imaging of FA-CDs as well as live/dead cell staining assay (calcein-AM/PI). These results demonstrate that the FA-CD/PPy-NPs can be utilized as multifunctional theranostic agents for specific bioimaging and treatment of FR-positive cancer cells.

Photochemical Activity of Black Phosphorus for Near‐Infrared Light Controlled In Situ Biomineralization

The photochemical activity of black phosphorus (BP) in near‐infrared (NIR) light controlled in situ biomineralization is investigated. Owing to the excellent NIR absorption, irradiation with NIR light not only promotes degradation of BP into PO4 3−, but also enhances the chemical activity to accelerate the reaction between PO4 3− and Ca2+ and promote in situ biomineralization. Mineralization of hydrogels is demonstrated by the preparation of BP incorporated hydrogel (BP@Hydrogel) which delivers greatly improved biomineralization performance under NIR illumination. The biomineralization process which can be controlled by modulating the light irradiation time and location has a high potential in controlling the mechanical properties and osteoinductive ability in tissue engineering. This study also provides insights into the degradation, photochemical activity, and new biological/biomedical applications of BP.

Synthesis of GO-Fe3O4-PANI nanocomposite with excellent NIR absorption property

Photothermal therapy is considered as an alternative to conventional cancer therapy methods, which is a mild practice compared to chemotherapy, radiotherapy, and surgery. The purpose of this study is to synthesize a photosensitizing agent having strong near-infrared (NIR) (˜808 nm) absorption, low cytotoxicity, magnetic properties, and excellent stability. For this purpose, graphene oxide-iron (II,III) oxide-polyaniline (GO-Fe3O4-PANI) was synthesized for the first time towards photothermal application and characterized by UV–vis, FTIR, XRD, TEM, and VSM analyses. The photothermal performance of the nanocomposite was investigated at various concentrations (0.1, 0.05, 0.025 mg/mL) under 1, 1.5, and 2.5 W/cm2 laser power density values. Photothermal conversion efficiency values of the samples were calculated by time constant method and a maximum of 65.80% efficiency was obtained (0.1 g/mL concentration at 1.5 W/cm2 for 5 min). This novel nanocomposite demonstrated superior results among PANI based photosensitizing agents.

Precursor reactivity differentiation for single-step preparation of Ag2Se@Ag2S core–shell nanocrystals with distinct absorption and emission properties enabling sensitive near-infrared photodetection

To obtain dual active near-infrared (NIR) nanomaterial with strong absorption and emission properties, we report herein a novel precursor reactivity differentiation strategy, i.e., utilizing 1-octadecene (ODE)–Se having the ability to react with Ag salts much stronger and faster than ODE–thiourea, for single-step preparation of Ag2Se@Ag2S nanocrystals (NCs). With this strategy, we were able to synthesize high-quality Ag2Se@Ag2S NCs with both excellent NIR absorption and emission properties. Particularly, these nanocrystals possess a rather strong and sharp excitonic absorption peak with a full width at half maximum less than 70 nm and a maximum fluorescence quantum yield as high as 24.3%. Their appealing optical properties and structural features were founded to be highly dependent on the Se to S precursor ratio in the reaction solutions, owing to such a ratio exerting a direct influence on the core sizes and shell thicknesses of the as-formed NCs. Taking advantage of their remarkable NIR absorption properties, self-powered photoelectrochemical-type photodetectors based on the as-prepared Ag2Se@Ag2S NCs were successfully fabricated, which demonstrate a much better response performance and photostability in comparison with those based on Ag2Se NCs.

Laser-induced fabrication of highly branched CuS nanocrystals with excellent near-infrared absorption properties**Project supported by National Natural Science Foundation of China (Grant Nos. 11575102, 11105085, 11405098, and 11375108) and the Fundamental Research Funds of Shandong University, China (Grant No. 2015JC007).

We report on the successful fabrication of highly branched CuS nanocrystals by laser-induced photochemical reaction. Surprisingly, the single-crystalline nature with preferential alignment of the (107) orientation can be well improved during the moderate growth process. The branch length drastically increases from about 5 nm to 6 μm with an increase of photochemical reaction time (0–40 min). The absorption spectra of as-prepared CuS nanodendrites show that localized surface plasmon resonance (LSPR) peaks can be modulated from about 1037 nm to 1700 nm with an increase of branch length. Our results have a promising potential for photodynamic therapy and biological imaging application.

Laser-induced fabrication of highly branched Au@TiO2 nano-dendrites with excellent near-infrared absorption properties

The highly branched Au@TiO2 nano-dendrites with excellent near-infrared absorption properties have been conveniently fabricated via a novel and effective laser-induced strategy.

Co-assembled T4-Cu4In16S35 and Cubic Cu12S8 Clusters: A Crystal Precursor for Near-Infrared Absorption Material

Recently, discrete large Tn clusters have become particularly attractive because they can be used as starting materials not only for constructing porous chalcogenides but also for solution processing of semiconductor film materials with electronic and optical properties. However, the discrete large clusters of main-group metal chalcogenides are difficult to stabilize because of their high negative charge. We report herein a new crystal compound co-assembled by discrete T4 [Cu4In16S35H4]14–and cubic [Cu12S8]4– clusters. It is uncommon that the negatively charged CuS cluster acts as a template to sustain a hexagonal cavity formed by negatively charged T4 clusters. Its degeneration product shows an excellent near-infrared absorption property and photocurrent responsive properties.

Fabrication of LaB6@SiO2/Au composite nanoparticles as a catalyst with near infrared photothermally enhanced activity

Citrate-capped Au nanoparticles have been assembled onto the surface of LaB6 nanoparticles with silica coating and amino-functionalization to develop the LaB6@SiO2/Au composite nanoparticles as a novel catalyst with near-infrared (NIR) photothermally enhanced activity. The basic properties including the morphology, size, structure, zeta potential, and optical property were characterized. They also confirmed the formation of LaB6-SiO2 core–shell structure and the successful assembling of highly dispersed Au nanoparticles on the surface. The resulting LaB6@SiO2/Au composite nanoparticles were demonstrated to possess the excellent NIR absorption and photothermal conversion properties of LaB6 cores and the catalytic capability of Au nanoparticles for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. Under NIR irradiation, they photothermally induced the heating of reaction medium and the presence of possible hot spots on the catalyst surface, leading to the enhancement in the reduction rate of 4-nitropeheol. This result will be helpful for the development of photothermally driven catalytic systems.

Synthesis of One-Dimensional Potassium Tungsten Bronze with Excellent near-Infrared Absorption Property

Potassium tungsten oxide nanofibers were successfully synthesized via a facile hydrothermal reaction route in the presence of sulfate. After reduction under a reductive atmosphere of H(2)(5 vol %)/N(2), the potassium tungsten oxide transformed to potassium tungsten bronze. Because of the lack of free electrons, the potassium tungsten oxide (K(x)WO(3+x/2)) showed no NIR shielding performance; however, the potassium tungsten bronze (K(x)WO(3)) showed promising optical characteristics such as high transmittance for visible light, as well as high shielding performance for near-infrared lights, indicating its potential application as a solar filter. Meanwhile, the potassium tungsten bronze (K(x)WO(3)) showed strong absorption of near-infrared light and instantaneous conversion of photoenergy to heat.