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- 实验方案
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Semiconducting Langmuir-Blodgett Films of Porphyrin Paddle-Wheel Frameworks for Photoelectric Conversion
摘要： Understanding the photocurrent transportation within porphyrin-containing metal-organic frameworks (PMOFs) will be a critical step for applying these materials in light-harvesting molecular devices in the future. Two copper porphyrin paddle-wheel frameworks (Cu-PPFs) were employed to study the influence of metal ions coordinated into the porphyrin ligands on conductivity and photoelectron transfer capability. To compare the electronic and optical properties of both materials, we prepared an ultra-thin film of each PPF via a Langmuir-Blodgett method. The resulting films exhibited uniform morphology and single-crystalline domains, in addition to photoelectric conversion capabilities. We confirmed both Cu-PPFs have semiconducting properties with an optical bandgap around 2.7 eV. The current density generated by both Cu-PPFs were studied through a mercury drop junction approach. We observed a slightly higher conductivity from the Cu-PPF film consisting of metalloporphyrins than the one without copper doping in the porphyrin centers. In addition, the copper ions coordinated porphyrins were found to be more favorable for facilitating photo-induced electron transfer from the Cu-PPF film to a conductive glass substrate. This work presents a new approach of combining thin film fabrication and electro-heterojunction measurement to study electron transfer within an ultra-thin film.
关键词： Metal-Organic Framework (MOF),2D Material,Langmuir-Blodgett Film,Self-Assembly,Semiconductor,Porphyrin Thin Film,Photoelectric Conversion
更新于2025-09-23 15:21:21
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Direct quantitative material decomposition employing grating-based X-ray phase-contrast CT
摘要： Dual-energy CT has opened up a new level of quantitative X-ray imaging for many diagnostic applications. The energy dependence of the X-ray attenuation is the key to quantitative material decomposition of the volume under investigation. This material decomposition allows the calculation of virtual native images in contrast enhanced angiography, virtual monoenergetic images for beam-hardening artifact reduction and quantitative material maps, among others. These visualizations have been proven beneficial for various diagnostic questions. Here, we demonstrate a new method of ‘virtual dual-energy CT’ employing grating-based phase-contrast for quantitative material decomposition. Analogue to the measurement at two different energies, the applied phase-contrast measurement approach yields dual information in form of a phase-shift and an attenuation image. Based on these two image channels, all known dual-energy applications can be demonstrated with our technique. While still in a preclinical state, the method features the important advantages of direct access to the electron density via the phase image, simultaneous availability of the conventional attenuation image at the full energy spectrum and therefore inherently registered image channels. The transfer of this signal extraction approach to phase-contrast data multiplies the diagnostic information gained within a single CT acquisition. The method is demonstrated with a phantom consisting of exemplary solid and fluid materials as well as a chicken heart with an iodine filled tube simulating a vessel. For this first demonstration all measurements have been conducted at a compact laser-undulator synchrotron X-ray source with a tunable X-ray energy and a narrow spectral bandwidth, to validate the quantitativeness of the processing approach.
关键词： Dual-energy CT,virtual non-contrast images,grating-based phase-contrast,electron density,effective atomic number,material decomposition,quantitative X-ray imaging,virtual monoenergetic images
更新于2025-09-23 15:21:21
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Graphene Adsorption and Separation Functional Materials
摘要： Graphene and its derivatives have highly been embraced in the development and application of new type of adsorption and separation functional materials, due to its unique structure and superior performance. This paper gives a comprehensive review to the recent studies about the adsorption and separation functional materials, including graphene, graphene oxide, graphene gel, graphene-based sponge, graphene separation membrane as well as graphene continuous oil absorption and separation materials. Moreover, the preparation methods and application prospect were mainly utilized to illustrate the research progress. Especially, we predict that layered graphene membrane and graphene continuous oil absorption and separation materials may be the most research worthy.
关键词： Functional Material,Adsorption,Graphene Oxide,Graphene,Separation
更新于2025-09-23 15:21:21
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Effects of material degradation on electrical and optical characteristics of surface dielectric barrier discharge
摘要： In this paper, screen-printed electrodes are asymmetrically fabricated on three different dielectrics (multi-layered polyimide, quartz, and alumina). Supplied with AC power, sustainable surface dielectric barrier discharge (SDBD) plasma is generated in atmospheric pressure. During plasma processing, different changes of material degradation and discharge images are observed. The corresponding electrical and optical characteristics are investigated by optical emission spectra (OES) and Lissajous figure analysis, respectively. It is found that both dielectric degradation and electrode erosion occur on the surface of the polyimide based SDBD device, while there is only electrode erosion for the quartz and alumina based devices, which results in different changes of electrical characteristics. OES calculated results show that with an increase of discharge aging time, electron temperature increases for the polyimide based SDBD device and decreases for quartz and alumina based SDBD devices, while all the gas temperatures of three dielectrics increase with the aging time. Furthermore, compared to vibrational temperature and gas temperature, the distribution of electron temperature is more suitable for evaluating the changes in discharge uniformity during plasma processing.
关键词： electrical characteristics,plasma processing,optical characteristics,surface dielectric barrier discharge,material degradation
更新于2025-09-23 15:21:21
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[IEEE 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - Erode (2018.2.15-2018.2.16)] 2018 Second International Conference on Computing Methodologies and Communication (ICCMC) - Optimization of N+ hetero pocket doped Dual metal Vertical TFET
摘要： In this paper, an N+ hetero pocket doped Dual metal Vertical TFET is proposed. Due to an additional tunneling contribution to current along the body thickness of the device the proposed device offers larger ON current and steeper subthreshold slope (SS) as compare to conventional Tunnel FET. Here, the n+ pocket doping is incorporated near the gate source overlap region. Moreover, the pocket material is optimized with different bandgap materials. The dual metal gate (DMG) is used and compared with single material gate (SMG). Further, with an n+ layer at the p-source side, improvements in the device performance in terms of on-current (10-3A), subthreshold swing, SS (39mV/dec) are achieved. The proposed device is optimized for channel length, silicon body layer thickness, source doping engineering, gate dielectric material. Finally, the analog performance of the device is examined and found the device is suitable for high frequency application.
关键词： Dual Material Gate (DMG),Vertical TFET,Single Material Gate(SMG),Band-to-band tunneling (BTBT)
更新于2025-09-23 15:21:01
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[Micro/Nano Technologies] Micro and Nano Fabrication Technology Volume 1 || Bonnet Polishing of Microstructured Surface
摘要： Microstructured surfaces have been adopted in various and wide applications. Different types of microstructures made of ductile materials can be generated by cutting process, for example, turning and milling with speci?ed diamond cutters. However, these processes generally are not capable to handle with hard and brittle materials which are called dif?cult-to-machine materials. Computer-controlled ultra-precision polishing with bonnet provides an enabling solution to generate microstructures due to its feasible in?uence function. With proper machining parameters, speci?ed shape of the tool in?uence function is hence obtained, and then with aid of tool path planning, microstructured surface topography is generated, especially for those dif?cult-to-machine materials. In this chapter, research work for generating microstructured surface by computer-controlled ultra-precision bonnet polishing is presented. The material removal characteris- tics and tool in?uence function of bonnet polishing are explained, and a multi- scale material removal model and a surface generation model were developed. Surface generation of microstructures by single precess polishing and swing precess polishing is explained in details. A series of simulation and real polishing experimental studies are undertaken based on a seven-axis ultra-precision freeform polishing machine. The generated microstructured surfaces with various patterns have been analyzed. The research results have demonstrated that the proposed bonnet polishing provides an enabling and effective approach for generating microstructured surfaces.
关键词： Modelling,Bonnet polishing,Ultra-precision machining,Dif?cult-to- machine material,Precess polishing,Surface generation,In?uence function,Computer controlled polishing,Microstructured surface,Multi-scale material removal,Simulation
更新于2025-09-23 15:21:01
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Hydroxymethyl Functionalized PEDOT-MeOH:PSS for Perovskite Solar Cells
摘要： Poly(hydroxymethylated-3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT-MeOH:PSS) conducting polymers are synthesized and incorporated in inverted structured perovskite solar cells (PVSCs) as hole transport materials. The highest occupied molecular orbital of PEDOT-MeOH is lowered by adding a hydroxymethyl (-MeOH) functional group to ethylenedioxythiophene (EDOT), and thus the work function of PEDOT-MeOH:PSS is increased. Additionally, hydrogen bonding can be formed among EDOT-MeOH monomers and between EDOT-MeOH monomers and sulfate groups on PSS, which promote PEDOT-MeOH chain growth and enhance PSS doping. The electronic, microstructural, and surface morphological properties of PEDOT-MeOH:PSS are modified by changing the amount of PSS and ferric oxidizing agent used in the polymerization and by adding ethylene glycol in the post-synthesis treatment. The PVSCs based on ethylene glycol treated PEDOT-MeOH:PSS overperform the PVSCs based on commercial PEDOT:PSS because of the better energetic alignment and the enhancement of PEDOT-MeOH:PSS electrical conductivity. This work opens the way to develop new hole transport materials for highly efficient inverted PVSCs.
关键词： hole transport material,perovskite,solar cell,electrical conductivity,work function
更新于2025-09-23 15:21:01
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Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties
摘要： Laser polishing of metals consists of irradiating the part’s surface with a laser beam, thus generating a molten layer that is redistributed and resolidified to create a surface with reduced roughness. However, the process is also characterized by an instantaneous formation of heat-affected zones with consequent microstructural changes that influence the mechanical properties. In order to understand the microstructural evolution during laser polishing of Ti-6Al-4V laser-based powder bed fusion samples, a thermal model is applied in the current study to predict the dimensions of the melted zones and the heat-affected areas. Furthermore, the results obtained through simulations are discussed and compared to the experimental data, thereby establishing the validity of the process models. Finally, the experimental studies also include the evaluation of material hardness and residual stresses after laser polishing.
关键词： laser polishing,thermal model,material properties,additive manufacturing,microstructure evolution
更新于2025-09-23 15:21:01
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Study on the intelligent model database modeling the laser welding for aerospace aluminum alloy
摘要： With the purpose of improving the modeling e?ciency, the model database is established targeting that in-telligent modeling of laser welding for aerospace aluminum alloy. The model database consists of material database, heat source model database and weld joint structure database. The aerospace aluminum alloys are classi?ed reasonably in order to establish the material model database which can manage the thermo-physical properties of aluminum alloys. The heat source models of laser welding are summarized to establish model database on the basis of the di?erent energy distribution characteristics. The joint structure database includes butt joint, T-joint and lap joint. Modeling of arbitrary structures can be implemented quickly and e?ciently when modelers invoke and assemble this model database. The ?nite element model is e?ciently established and accurately solved by taking the 5A90 and 2219 aluminum alloy laser welding as an example. Finally, it is found that the model database established in this paper can greatly improve the modeling e?ciency of laser welding numerical simulation.
关键词： Laser welding,Model database,Aluminum alloy,Structural model,Heat source model,Material model
更新于2025-09-23 15:21:01
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Anthradithiophene based hole-transport material for efficient and stable perovskite solar cells
摘要： A novel hole-transport material (HTM) based on an anthradithiophene central bridge named BTPA-7 is developed. In comparison to spiro-OMeTAD (2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene), the synthetic steps of BTPA-7 are greatly reduced from 6 to 3 and the synthetic cost of BTPA-7 is nearly a half that of spiro-OMeTAD. Moreover, BTPA-7 exhibits a relatively lower conductivity but higher hole mobility and higher glass transition temperature (Tg) than spiro-OMeTAD. Compared with the photovolatic performance for spiro-OMeTAD, FA0.85MA0.15PbI3 and MAPbI3 PSC devices based on BTPA-7 exhibit slightly lower PCEs with the values of 17.58% (18.88% for spiro-OMeTAD) and 11.90% (13.25% for spiro-OMeTAD), respectively. Nevertheless, a dramatically higher Jsc of PSC based on BTPA-7 is achieved, which arises from the higher hole mobility of BTPA-7. In addition, the relatively hydrophobic character of BTPA-7 eventually enhances the PSC device stability. Lower cost, higher hole mobility, higher Tg, satisfactory photovoltaic performance, and superior device stability of BTPA-7 can be utilized as a substitute for spiro-OMeTAD in PSCs.
关键词： Stability,Anthradithiophene,Hole-transport material,Synthetic cost
更新于2025-09-23 15:21:01