Conducting Helical Structures from Celery Decorated with a Metallic Conjugated Polymer Give Resonances in the Terahertz Range

A method to decorate cellulose‐based helices retrieved from the plant celery with a conductive polymer is proposed. Using a layer‐by‐layer method, the decoration of the polyanionic conducting polymer poly(4‐(2,3‐dihydrothieno [3,4‐b]‐[1,4]dioxin‐2‐yl‐methoxy)‐1‐butanesulfonic acid (PEDOT‐S) is enhanced after coating the negatively charged cellulose helix with a polycationic polyethyleneimine. Microscopy techniques and two‐point probe are used to image the structure and measure the conductivity of the helix. Analysis of the optical and electrical properties of the coated helix in the terahertz (THz) frequency range shows a resonance close to 1 THz and a broad shoulder that extends to 3.5 THz, consistent with electromagnetic models. Moreover, as helical antennas, it is shown that both axial and normal modes are present, which are correlated to the orientation and antenna electrical lengths of the coated helices. This work opens the possibility of designing tunable terahertz antennas through simple control of their dimensions and orientation.     

抗红外烟幕遮蔽剂CuCl2-NiCl2-GIC的研究

采用定量混合法,以微粉石墨为主体材料合成出2、3阶CuCl2-NiCl2-GIC,应用XRD技术对其层间结构进行表征,结果证实所得产物以混阶形式存在,其中2、3阶CuCl2-NiCl2-GIC的特征层间距为1．474nm和1．753nm。用扫描电镜观测样品的表观形貌,并进行选区成份分析。通过考核CuCl2—NiCl2—GIC的粒度分布、沉降速度及质量消光系数,证实该物质对工作在红外波段的军用电子器材具有良好的干扰功效。     

PEGylated Micelle Nanoparticles Encapsulating a Non‐Fluorescent Near‐Infrared Organic Dye as a Safe and Highly‐Effective Photothermal Agent for In Vivo Cancer Therapy

Photothermal therapy (PTT), as a minimally invasive and highly effective cancer treatment approach, has received widespread attention in recent years. Tremendous effort has been devoted to explore various types of photothermal agents with high near‐infrared (NIR) absorbance for PTT cancer treatment. Despite many exciting progresses in the area, effective yet safe photothermal agents with good biocompatibility and biodegradability are still highly desired. In this work, a new organic PTT agent based on polyethylene glycol (PEG) coated micelle nanoparticles encapsulating a heptamethine indocyanine dye IR825 is developed, showing a strong NIR absorption band and a rather low quantum yield, for in vivo photothermal treatment of cancer. It is found that the IR825–PEG nanoparticles show ultra‐high in vivo tumor uptake after intravenous injection, and appear to be an excellent PTT agent for tumor ablation under a low‐power laser irradiation, without rendering any appreciable toxicity to the treated animals. Compared with inorganic nanomaterials and conjugated polymers being explored in PTT, the NIR‐absorbing micelle nanoparticles presented here may have the least safety concern while showing excellent treatment efficacy, and thus may be a new photothermal agent potentially useful in clinical applications.     

提高短波红外光谱仪信噪比的均衡曝光技术

针对短波红外焦平面光谱仪传统曝光方式在一大类应用场景中的不足之处,提出了一种提高短波红外焦平面光谱仪成像信噪比的均衡曝光技术:即给予焦平面上不同光谱维以不同的积分时间来提高整个焦平面的成像信噪比.实验系统包括中科院上海技术物理研究所自主研制的短波红外焦平面探测器、探测器驱动电路、信号采集与处理电路、上位机软件等.实验对比了3.31 ms、5.76 ms、8.22 ms、10.68 ms、13.14 ms这5档积分时间的信噪比及其对比,经过测试,在忽略驱动及读出电路噪声的情况下,实验值与理论值接近,该技术有效提高了红外光谱仪成像信噪比.     

Molecular Imaging in the Second Near‐Infrared Window

In the past decade, noticeable progress has been achieved regarding fluorescence imaging in the second near‐infrared (NIR‐II) window. Fluorescence imaging in the NIR‐II window demonstrates superiorities of deep tissue penetration and high spatial and temporal resolution, which are beneficial for profiling physiological processes. Meanwhile, molecular imaging has emerged as an efficient tool to decipher biological activities on the molecular and cellular level. Extending molecular imaging into the NIR‐II window would enhance the imaging performance, providing more detailed and accurate information of the biological system. In this progress report, selected achievements made in NIR‐II molecular imaging are summarized. The organization of this report is based on strategies underlying rational designs of NIR‐II imaging probes, and their applications in molecular imaging are highlighted. This progress report may provide guidance and reference for further development of functional NIR‐II probes designed for high‐performance molecular imaging.     

Near‐Infrared Absorbing Polymeric Nanoparticles as a Versatile Drug Carrier for Cancer Combination Therapy

Poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) nanoparticles, after being coated with polyethylene glycol (PEG), are used as a drug carrier to load various types of aromatic therapeutic molecules, including chemotherapy drugs doxorubicin (DOX) and SN38, as well as a photodynamic agent chlorin e6 (Ce6), through π–π stacking and hydrophobic interaction. Interesting functionalities of PEDOT:PSS‐PEG as an unique versatile drug delivery platform are discovered. Firstly, for water‐insoluble drugs such as SN38, the loading on PEDOT:PSS‐PEG dramatically enhances its water solubility, while maintaining its cytotoxicity to cancer cells. Secondly, the delivery of Ce6 by PEDOT:PSS‐PEG is able to remarkably accelerate the cellular uptake of Ce6 molecules, and thus offers improved photodynamic therapeutic efficacy. Using DOX‐loaded PEDOT:PSS‐PEG as the model system, it is demonstrated that the photothermal effect of PEDOT:PSS‐PEG can be utilized to promote the delivery of this chemotherapeutic agent, achieving a combined photothermal‐ and chemotherapy with an obvious synergistic cancer killing effect. Moreover, it is also shown that multiple types of therapeutic agents could be simultaneously loaded on PEDOT:PSS‐PEG nanoparticles and delivered into cancer cells. This work highlights the great potential of NIR‐absorbing polymeric nanoparticles as multifunctional drug carriers for potential cancer combination therapy with high efficacy.     

Near‐Infrared Laser‐Triggered Nitric Oxide Nanogenerators for the Reversal of Multidrug Resistance in Cancer

The potential therapeutic implications of nitric oxide (NO) for diverse diseases have been under consideration for years; however, the development of precisely controllable NO generation system with potential for clinical application has remained elusive. Herein, intelligent near‐infrared (NIR) laser‐triggered NO nanogenerators for the treatment of multidrug‐resistant (MDR) cancer are fabricated by integrating photothermal agents and heat‐sensitive NO donors into a single nanoparticle. Such nanogenerators can absorb 808 nm NIR photons and convert them into ample heat to trigger NO release. The generated NO molecules are demonstrated to successfully achieve multidrug‐resistance reversal by inhibiting the expression of P‐glycol protein. Consequently, the intracellular accumulation of doxorubicin is effectively increased, resulting in high toxicity to MDR cancer cells in vitro. By virtue of surface modification with targeting ligands, these nanoparticles are able to selectively accumulate in tumor tissue. The therapeutic effects of the nanogenerators are validated in a humanized MDR cancer model. The in vivo experiment indicates that the nanoparticles possess excellent tumor suppression functionality with few side effects upon NIR laser exposure. Therefore, this novel photothermal conversion‐based NO‐releasing platform is expected to be a potential alternative to clinical MDR cancer treatment and may provide insights with regard to other NO‐relevant medical treatments.     

低温PECVD法形成纳米级介质膜微观结构研究

采用俄歇电子能谱 ( AES)和傅里叶红外光谱 ( FTIR)分析低温 PECVD法形成纳米级 Si Ox Ny 介质膜的微观组分结构及其与制膜工艺间关系 ,通过椭圆偏振技术测试该薄膜的物理光学性能。研究结果表明 :该介质膜中氮、氧等元素均匀分布 ,界面处元素含量变化激烈 ;高、低反应气压变化对膜内微观组分影响有异 ;该薄膜是既含有类似 Si3N4 、又含有类似 Si O2 的非晶状态 ,呈现无序网络结构 ;随着含氮量或含氧量的增多 ,该膜分别向Si3N4 或 Si O2 成分较多的结构转化 ;优化制膜工艺形成的富氮 Si Ox Ny 膜的性能与结构方面得到提高。     

Chemiluminescence‐Generating Nanoreactor Formulation for Near‐Infrared Imaging of Hydrogen Peroxide and Glucose Level in vivo

Water‐dispersed all‐in‐one nanoprobes composed of densely integrated peroxyoxalate fuel and a cyanine dye are formulated to optimize the nanoscopic chemiluminescence reaction. It is demonstrated that the chemiluminescent nanoformulation can generate bright near‐infrared signal in response to external hydrogen peroxide that is biologically implicated with cell signaling and diseases. Successful imaging of endogenously overproduces hydrogen peroxide and indirect determination of glucose level in vivo with the chemiluminescent nanoprobes offers an opportunity for early diagnosis of diseases.     

A Ratiometric Near‐Infrared Fluorescent Probe for Quantification and Evaluation of Selenocysteine‐Protective Effects in Acute Inflammation

Selenocysteine (Sec) is a primary kind of reactive selenium species in cells whose antioxidant roles in a series of liver diseases have been featured. However, it is difficult to determine Sec in living cells and in vivo due to its high reactivity and instability. This work reports a ratiometric near‐infrared fluorescent probe (Cy‐SS) for qualitative and quantitative determination of Sec in living cells and in vivo. The probe is composed of heptamethine cyanine fluorophore, the response unit bis(2‐hydroxyethyl) disulfide, and the liver‐targeting moiety d ‐galactose. Based on a detection mechanism of selenium–sulfur exchange reaction, the concentrations of Sec in HepG2, HL‐7702 cells, and primary mouse hepatocytes is determined as 3.08 ± 0.11 × 10^?6m , 4.03 ± 0.16 × 10^?6m and 4.34 ± 0.30 × 10^?6m , respectively. The probe can selectively accumulate in liver. The ratio fluorescence signal of the probe can be employed to quantitatively analyze the fluctuation of Sec concentrations in cells and mice models of acute hepatitis. The experimental results demonstrate that Sec plays important antioxidant and anti‐inflammatory roles during inflammatory process. And the levels of intracellular Sec have a close relationship with the degree of liver inflammation. The above imaging detections make this new probe a potential candidate for the accurate diagnosis of inflammation.     

Gold Nanoframeworks with Mesopores for Raman–Photoacoustic Imaging and Photo‐Chemo Tumor Therapy in the Second Near‐Infrared Biowindow

Gold‐based nanostructures with tunable wavelength of localized surface plasmon resonance (LSPR) in the second near‐infrared (NIR‐II) biowindow receive increasing attention in phototheranostics. In view of limited progress on NIR‐II gold nanostructures, a particular liposome template‐guided route is explored to synthesize novel gold nanoframeworks (AuNFs) with large mesopores (≈40 nm) for multimodal imaging along with therapeutic robustness. The synthesized AuNFs exhibit strong absorbance in NIR‐II region, affording their capacity of NIR‐II photothermal therapy (PTT) and photoacoustic (PA) imaging for deep tumors. Functionalization of AuNFs with hyaluronic acid (HA) endows the targeting capacity for CD44‐overexpressed tumor cells while gatekeeping doxorubicin (DOX) loaded into mesopores. Conjugation of Raman reporter 4‐aminothiophenol (4‐ATP) onto AuNFs yields a surface‐enhanced Raman scattering (SERS) fingerprint for Raman spectroscopy/imaging. In vivo evaluation of HA‐4‐ATP‐AuNFs‐DOX on tumor‐bearing xenografts demonstrates its high efficacy in eradication of solid tumors in NIR‐II under PA–Raman dual image‐guided photo‐chemotherapy. Thus, current AuNFs offer versatile capabilities for phototheranostics.     

Optical Gain in the Near Infrared by Light‐Emitting Electrospun Fibers

The potential integration of polymer nanofibers in photonic devices and circuits is a major driver for research on their waveguiding and optical gain properties. Emission in the near‐infrared is especially important in this framework in view of the realization of nanofiber‐based optical amplifiers. Here, the optical gain properties of electrospun fibers embedding near‐infrared light‐emitting molecules are investigated. Upon pulsed optical pumping, line narrowing typical of amplified spontaneous emission is observed, with gain of 5.5 cm^?1 and threshold fluence down to 0.25 mJ cm^?2. Importantly, the stimulated emission characteristics are strongly dependent on individual fiber characteristics and on the mutual alignment of nanofibers in arrays, thus being tailorable through the fiber architecture and assembling. These results open interesting perspectives for the exploitation of electrospun fibers as active components in the near‐infrared range.     

Ultrahigh Gain Polymer Photodetectors with Spectral Response from UV to Near‐Infrared Using ZnO Nanoparticles as Anode Interfacial Layer

Significant increase of photocurrent upon UV light exposure is demonstrated in a narrow‐bandgap polymer‐based photodetector using ZnO nanoparticles as anode interfacial layer. The phenomenon is attributed to the UV light illumination induced oxygen molecules desorption from surface of ZnO nanoparticles, which reduces the electron injection barrier at the anode interface. Ultrahigh external quantum efficiency of 140 000% and extremely low gain threshold voltage of 1.5 mV are achieved in this device with 30 s UV light irradiation. The gain mechanism is explained by the fast transit and replenishment of photogenerated electrons within their lifetime, which is prolonged by the electron‐only device structure, and the experiment results fit well with the proposed photoconductive model.     

“Layer‐Filter Threshold” Technique for Near‐Infrared Laser Ablation in Organic Semiconductor Device Processing

Although conventional laser ablation (CLA) method has widely been used in patterning of organic semiconductor thin films, its quality control still remains unsatisfied due to the ambiguous photochemical and photothermal processes. Based on industrial available near‐infrared laser source, herein, a novel “layer‐filter threshold” (LFT) technique is proposed, which involves the decomposition of targeted “layer‐filter” and subsequent explosive evaporation process to purge away the upper layers instead of layer‐by‐layer ablation. For photovoltaic device with structure of metal/blend/PEDOT:PSS/ITO/glass, the PEDOT:PSS layer as the “layer‐filter” is first demonstrated to be effective, and then the merged P1–P2 line and metal electrode layer are readily patterned through the “self‐aligned” effect and regulation of ablation direction, respectively. The correlation between laser fluence and explosive ablation efficacy is also investigated. Finally, photovoltaic modules based on classical P3HT:PC₆₁BM and low‐bandgap PBDT‐TFQ:PC₇₁BM systems are separately fabricated following the LFT technique. It is found that over 90% of geometric fill factor is achieved while device performances maintain in a limited change with increased number of series cells. In comparison to conventional laser ablation methods, the LFT technique does not require sophisticated instruments but reaches comparable processing accuracy, which shows promising potential in the fabrication and commercialization of organic semiconductor thin‐film devices.     

Color Noise Reduction Method in Non‐constant Luminance Signal for High Dynamic Range Video Service

A high dynamic range (HDR) video service is an upcoming issue in the broadcasting industry. For compatibility with legacy devices receiving a non‐constant luminance (NCL) signal, new tools supporting an HDR video service are required. The current pre‐processing chain of HDR video can produce color noise owing to the chroma component down‐sampling process for video encoding. Although a luma adjustment method has been proposed to solve this problem, some disadvantages still remain. In this paper, we present an adaptive color noise reduction method for an NCL signal of an HDR video service. The proposed method adjusts the luma component of an NCL signal adaptively according to the information of the luma component from a constant luminance signal and the level of color saturation. Experiment results show that the color noise problem is resolved by applying our proposed method. In addition, the speed of the pre‐processing is increased more than two‐fold compared to a previous method.     

新一代厘米——分米波射电日像仪系统延时校准方法研究

射电日像仪是采用综合孔径方法成像,具有高时间、高空间和高频率分辨率的太阳专用射电望远镜.为了使信号相关值准确,需要精确测量系统的延时,在太阳成像相关前扣除,消除消调函数对可见度函数值的影响.同时延时的测量精度影响数字补偿精度、图像信噪比等信息,是其成像质量的关键,也是超宽频带和高时间分辨率情况下研制和实施的难点.本文研究了应用于我国在建的厘米——分米波射电日像仪,以太阳为校准源,闭合差方法得到系统延时差,并通过试验验证,得到优于1ns补偿精度.     

A Molecular Brush Approach to Enhance Quantum Yield and Suppress Nonspecific Interactions of Conjugated Polyelectrolyte for Targeted Far‐Red/Near‐Infrared Fluorescence Cell Imaging

A red‐fluorescent conjugated polyelectrolyte (CPE, P2 ) is grafted with dense poly(ethylene glycol) (PEG) chains via click chemistry and subsequently modified with folic acid to form a molecular brush based cellular probe ( P4 ). P4 self‐assembles into a core–shell nanostructure in aqueous medium with an average size of 130 nm measured by laser light scattering. As compared to P2 , P4 possesses not only a substantially higher quantum yield (11%), but also reduced nonspecific interactions with biomolecules in aqueous medium due to the shielding effect of PEG. In conjunction with its high photostability and low cytotoxicity, utilization of P4 as a far‐red/near‐infrared cellular probe allows for effective visualization and discrimination of MCF‐7 cancer cells from NIH‐3T3 normal cells in a high contrast, selective, and nonviral manner. This study thus demonstrates a flexible molecular brush approach to overcome the intrinsic drawbacks of CPEs for advanced bioimaging applications.     

Unraveling the Gain Mechanism in High Performance Solution‐Processed PbS Infrared PIN Photodiodes

High gain and low dark current solution‐processed colloidal PbS quantum dots infrared (IR) PIN photodetectors with IR sensitivity up to 1500 nm are demonstrated. The low dark current is due to the P‐I‐N structure with both electron and hole blockers. The high gain in our IR photodiodes is due to the enhancement of electron tunneling injection through the 1,1‐bis[(di‐4‐tolylamino) phenyl]cyclohexane (TAPC) electron blocker under IR illumination resulting from a distorted electron blocking barrier in the presence of photo‐generated holes trapped in the TAPC electron blocker. It is further found that the trap states in the TAPC layer are generated by the Ag atoms penetrated in the TAPC layer during the thermal evaporation process. The resulting photodetectors have a high detectivity value of 7 × 10¹³ Jones, which is even higher than that of a commercial InGaAs photodiode.     

Efficient Near‐Infrared Emission by Adjusting the Guest–Host Interactions in Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Thermally activated delayed fluorescence materials can effectively achieve high efficiency by harvesting singlet and triplet excitons in organic light‐emitting diodes (OLEDs). However, the choice of host material has a huge impact on the efficiency of the device, especially for the near‐infrared (NIR) luminescent material. In this contribution, a series of host materials are used to match the thermally activated delayed fluorescence emitter, 3,4‐bis(4‐(diphenylamino)phenyl)acenaphtho[1,2‐b]pyrazine‐8,9‐dicarbonitrile (APDC‐DTPA), for fabricating NIR OLEDs. All the host materials have the higher triplet energy than that of APDC‐DTPA. As the organometallic compound of Zn(BTZ)₂ has relatively stronger dipole moment, the electroluminescence spectral peak of doped device shows strong bathochromic shift exceeding 700 nm and changes with doping concentration. Finally, the extremely high external quantum efficiency of 7.8% (with 10 wt% of doping concentration) and 5.1% (with 20 wt% of doping concentration) are achieved with the emission peaks of 710 and 728 nm, respectively, which are superior to that of the device based on the other host materials. The approach is feasible to achieve bathochromic shift and highly efficient fluorescent OLEDs.     

Naphthothiadiazole‐Based Near‐Infrared Emitter with a Photoluminescence Quantum Yield of 60% in Neat Film and External Quantum Efficiencies of up to 3.9% in Nondoped OLEDs

Fluorescent emitters have regained intensive attention in organic light emitting diode (OLED) community owing to the breakthrough of the device efficiency and/or new emitting mechanism. This provides a good chance to develop new near‐infrared (NIR) fluorescent emitter and high‐efficiency device. In this work, a D‐π‐A‐π‐D type compound with naphthothiadiazole as acceptor, namely, 4,4′‐(naphtho[2,3‐c][1,2,5]thiadiazole‐4,9‐diyl)bis(N,N ‐diphenylaniline) (NZ2TPA), is designed and synthesized. The photophysical study and density functional theory analysis reveal that the emission of the compound has obvious hybridized local and charge‐transfer (HLCT) state feature. In addition, the compound shows aggregation‐induced emission (AIE) characteristic. Attributed to its HLCT mechanism and AIE characteristic, NZ2TPA acquires an unprecedentedly high photoluminescent quantum yield of 60% in the neat film, which is the highest among the reported organic small‐molecule NIR emitters and even exceeds most phosphorescent NIR materials. The nondoped devices based on NZ2TPA exhibit excellent performance, achieving a maximum external quantum efficiency (EQE) of 3.9% with the emission peak at 696 nm and a high luminance of 6330 cd m^?2, which are among the highest in the reported nondoped NIR fluorescent OLEDs. Moreover, the device remains a high EQE of 2.8% at high brightness of 1000 cd m^?2, with very low efficiency roll‐off.