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Practical methodology for <i>in situ</i> measurement of micro flow rates using laser diode absorption sensors
摘要： A laser diode-based flowmeter based on the infrared absorption method that can measure in situ micro flow rates from 0.2 to 20 ml h?1 was developed. A 1450 nm laser absorbed in water was irradiated to form a heated spot at 0 mm, and the temperature was measured upstream and downstream of the heated spot. The flow rate was measured by the temperature difference obtained by two diode lasers and photodetectors upstream and downstream of the heated spot. We measured the temperature profile of the flow rate by changing the temperature measurement position and the heating laser energy upstream and downstream of the heated spot, and compared the measurements with the simulation results. As the flow rate increased, the temperature profile shifted downstream, and the measured temperature upstream and downstream were analyzed according to the flow rate. The flow measurement range was adjusted according to the temperature measurement position. Increasing the energy of the heating laser also improved the measurement accuracy in the lower flow range. The developed flowmeter was calibrated by the gravimetric method, and the deviation and measurement uncertainty according to the flow rate were obtained. The maximum measurement uncertainty was 6.8% at a 1 ml h?1 flow rate, and the minimum measurement uncertainty was 1.78% at 8 ml h?1. Thus, it was confirmed that the flow rate can be measured through the temperature difference gauged using a simple diode laser set. Using the laser diode-based flowmeter developed in this study, one can measure the flow rate in situ without injecting contaminants, such as particles, for measurements without cutting the piping. In addition, it can be manufactured in a miniaturized form at a low cost, and thus, it can be used for multi-drug infusion analysis, semiconductor process monitoring, etc.
关键词： near infrared absorption,diode laser,micro flow rate,thermal mass flowmeter
更新于2025-11-25 10:30:42
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Polyethylene glycol–modified molybdenum oxide as NIR photothermal agent and its ablation ability for HeLa cells
摘要： Molybdenum oxide, as one of the important transition metal semiconductor materials with photothermal property, has received increasing attention in the field of catalysis, sensing, energy storage, and clinical biomedicine. To improve its certain limitations such as poor biocompatibility and easy agglomeration during application as biomaterials and promote its performance as photothermal agent in biomedical fields, polyethylene glycol (PEG)–modified molybdenum oxide was synthesized and the synthesis conditions during the hydrothermal process, including the pH values and the amount of PEG added, were adjusted. Owing to the reduction function of PEG, as-obtained PEG-MoOx showed good photostability and colloidal stability, which were beneficial to its application in long-term clinical photothermal therapy. In addition, cell experiments indicated that PEG-MoOx particles exhibited low cytotoxicity and ability of photothermal killing for HeLa cells. With the increase PEG-MoOx particles in solution, the photothermal ablation ability of PEG-MoOx particles for the HeLa cells was enhanced under an 808-nm NIR laser irradiation. Hence, PEG-MoOx particles have great potential in the photothermal treatment of diseases.
关键词： Photothermal ablation,PEG,Molybdenum oxide,Near-infrared absorption,HeLa cells
更新于2025-09-19 17:15:36
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Flower-like Fe7S8/Bi2S3 Superstructures with Improved Near-Infrared Absorption for Efficient Chemo-Photothermal Therapy
摘要： Although various photothermal therapy (PTT) nanoagents have been developed in recent years, the rational design and easy synthesis of a PTT nanoplatform with improved near-infrared (NIR) absorption remains challenging. Herein, via a facile one-pot solvothermal strategy, hydrophilic nanosheet-assembled flower-like Fe7S8/Bi2S3 superstructures were fabricated successfully. Such nanoflowers exhibit improved NIR absorption, which is 1.54 times higher than that of pure Bi2S3 nanosheets at a wavelength of 808 nm. Attractively, these nanoflowers could be served as a drug delivery carrier with controlled release under pH/NIR stimuli, and display fascinating chemo-photothermal synergetic therapeutic effect both in vitro and in vivo. The resulting nanoflowers may open up a way for the design of other nanoagents with improved NIR absorption as well as chemo-photothermal cancer therapy effect.
关键词： Fe7S8/Bi2S3,chemotherapy,nanoflowers,photothermal therapy,near-infrared absorption,drug delivery
更新于2025-09-19 17:15:36
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Cobalt/Manganese Oxides as Theragnosis Nanoplatforms With Magnetic Resonance/Near-Infrared Imaging for Efficient Photothermal Therapy of Tumors
摘要： The combination of near-infrared (NIR) response and imaging response is a hot research area in which the functions of nanomaterials are maximized. However, the types of such materials reported so far present problems such as requiring complex synthesis. In this study, hydrophilic, porous, and hollow cobalt/manganese oxide (CMO) nanocrystals (NCs) were successfully prepared via a facile and green hydrothermal route. The CMO NCs show strong near-infrared (NIR) absorption, which results from their defect structure due to the coexistence of Co2+ and Co3+ in the as-prepared CMO NCs. Thus, the CMO NCs exhibit excellent photothermal performance, showing photothermal efficiency of up to 43.2%. In addition, the CMO NCs possess good magnetic resonance (MR) imaging performance, with longitudinal relaxivity (r1) of up to 3.48 mM?1 s?1. Finally, for the first time, we prove that the CMO nanocrystals are a promising photothermal agent. Our work provides insights into the application of Mn-based control agents and photothermal agents for photothermal theragnosis therapy.
关键词： cobalt/manganese oxides,photothermal agents,magnetic resonance imaging,photothermal theragnosis therapy,near-infrared absorption
更新于2025-09-16 10:30:52
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Design of New n-Type Porphyrin Acceptors with Subtle Side-Chain Engineering for Efficient Nonfullerene Solar Cells with Low Energy Loss and Optoelectronic Response Covering the Near-Infrared Region
摘要： A series of tailor-made highly efficient and near-infrared porphyrin-based acceptors is designed and synthesized for fullerene-free bulk-heterojunction (BHJ) organic solar cells (OSCs). Constructing BHJ active layers using a PTB7-Th donor and porphyrin acceptors (P-x), which have complementary absorption, accomplish panchromatic photon-to-current conversion from 300 to 950 nm. Our study shows that side-chains of the porphyrin acceptors fairly influences the molecular ordering and nanomorphology of the BHJ active layers. Significantly, porphyrin acceptor with four dodecoxyl side-chains (P-2) achieves an open-circuit voltage (VOC) of 0.80 V, a short-circuit current density (JSC) of 13.94 mA cm-2, a fill factor (FF) of 64.8%, and overall power conversion efficiency (PCE) of 7.23%. This great performance is attributable to the ascendant light-harvesting capability in the visible and NIR region, a high-lying LUMO energy level, a relatively high and more balanced carrier mobilities, and more ordered face-on molecular packing, which is beneficial for obtaining high VOC and JSC.
关键词： near-infrared absorption,porphyrins,organic solar cells,nonfullerene acceptors,n-type porphyrins
更新于2025-09-12 10:27:22
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An A–D–D–A-type non-fullerene small-molecule acceptor with strong near-infrared absorption for high performance polymer solar cells
摘要： An acceptor–donor–donor–acceptor (A–D–D–A)-type near-infrared non-fullerene small-molecule acceptor IDT2-DFIC with indacenodithiophene–indacenodithiophene (IDT2) as a donating core and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as electron withdrawing end groups has been synthesized. Compared to A–D–A-type small-molecule acceptor IDIC-4F, IDT2-DFIC exhibits a low optical bandgap of 1.42 eV with strong absorption in the 450–874 nm region, and upshifted energy levels as an electron acceptor. Furthermore, the IDT2-DFIC-based devices exhibited higher and more balanced charge transport and smoother surface morphology. The power conversion efficiency (PCE) of the IDT2-DFIC-based devices is 10.06%, which is higher than that of the IDIC-4F-based devices (5.17%). Our work provides an efficient molecular design strategy to construct small molecule acceptors with near-infrared absorption.
关键词： IDT2-DFIC,near-infrared absorption,A–D–D–A-type,non-fullerene small-molecule acceptor,polymer solar cells
更新于2025-09-12 10:27:22
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Perfect near-infrared absorption of graphene with hybrid dielectric nanostructures
摘要： Near-infrared perfect wave harvesting of graphene is theoretically and numerically obtained in a hybrid dielectric configuration without assistance of a reflecting mirror. The absorption is increased 43-fold compared to a suspended graphene layer at normal incidence. The mechanism of perfect absorption is based on critical coupling with a guided resonance introduced by a silicon bar array and Fabry–Perot (FP) effect of a silicon oxide layer. This lossless design is expected to find applications to allow the active area with effective generation and fast transport of photocarriers, paving a new way for on-chip small-footprint ultrahigh responsivity and ultrahigh-speed photodetection in silicon photonics.
关键词： guided resonance,near-infrared absorption,hybrid dielectric nanostructures,graphene,Fabry–Perot effect,critical coupling
更新于2025-09-12 10:27:22
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Small Band gap Boron Dipyrromethene-Based Conjugated Polymers for All-Polymer Solar Cells: The Effect of Methyl Units
摘要： Naphthalene diimide (NDI)-based conjugated polymers have been widely used as the nonfullerene electron acceptor for all-polymer solar cells (all-PSCs), but their low absorption coefficient in the near-infrared (NIR) region severely limits the light harvesting ability in solar cells and hence lowers their photovoltaic performance. In this work, two narrow band gap donor?acceptor conjugated polymers based on boron dipyrromethene (BODIPY) as the electron-deficient unit were developed as the electron donor to combine with a NDI-polymer acceptor in order to significantly improve the photoresponse in the NIR region. More importantly, we found that methyl substitution on the BODIPY segment played an important role in charge transport in these polymers. When methyl units were attached to the α-position of BODIPY, the polymer PMBBDT exhibited high-lying energy levels, improved crystallinity, and dramatically high hole mobility compared to the polymer PBBDT without methyl substitution. Consequently, the power conversion efficiencies (PCEs) could be enhanced from 0.32% for PBBDT- to 5.8% for PMBBDT-based all-PSCs, and the photoresponse covered from 300 to 900 nm. Our results demonstrate that methyl-substituted BODIPY-based conjugated polymers are promising candidates to solve the NIR absorption issue in NDI polymers and, therefore, can be potentially used to further boost the PCEs of all-PSCs similar with organic solar cells based on NIR-fused ring electron acceptors.
关键词： Boron dipyrromethene,Methyl substitution,Conjugated polymers,Near-infrared absorption,All-polymer solar cells
更新于2025-09-11 14:15:04
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Recent Advances on Nitrofluorene Derivatives: Versatile Electron Acceptors to Create Dyes Absorbing from the Visible to the Near and Far Infrared Region
摘要： Push–pull dyes absorbing in the visible range have been extensively studied so that a variety of structures have already been synthesized and reported in the literature. Conversely, dyes absorbing in the near and far infrared region are more scarce and this particularity relies on the following points: difficulty of purification, presence of side-reaction during synthesis, low availability of starting materials, and low reaction yields. Over the years, several strategies such as the elongation of the π-conjugated spacer or the improvement of the electron-donating and accepting ability of both donors and acceptors connected via a conjugated or an aliphatic spacer have been examined to red-shift the absorption spectra of well-established visible dyes. However, this strategy is not sufficient, and the shift often remains limited. A promising alternative consists in identifying a molecule further used as an electron-accepting group and already presenting an absorption band in the near infrared region and to capitalize on its absorption to design near and far infrared absorbing dyes. This is the case with poly(nitro)fluorenes that already exhibit such a contribution in the near infrared region. In this review, an overview of the different dyes elaborated with poly(nitro)fluorenes is presented. The different applications where these different dyes have been used are also detailed.
关键词： Knoevenagel reaction,near infrared absorption,fluorene,poly(nitro)fluorene,push–pull chromophore,nitrofluorene
更新于2025-09-09 09:28:46
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Ultrathin tungsten bronze nanowires with efficient photo-to-thermal conversion behavior
摘要： In this work, we describe a simple one-step solvothermal method to synthesize ultrathin quaternary tungsten bronze nanowires (QTBNWs). In addition, a series of alkali metal-doped QTBNWs can be prepared by simply changing the type of starting alkali carbonate and tungstate. The as-synthesized QTBNWs exhibits strong near-infrared (NIR) rays absorption, high visible light transmission and excellent photo-to-thermal conversion behavior, which are superior to those of tungsten bronze nanorods and ternary TBNWs. And its excellent photothermal performance should be attributed to great localized surface plasmon resonances (SPR).
关键词： solvothermal method,photo-to-thermal conversion,near-infrared absorption,ultrathin tungsten bronze nanowires,surface plasmon resonances
更新于2025-09-09 09:28:46