- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of Thionation on the Performance of PNDIT2-Based Polymer Solar Cells
摘要： All-polymer solar cells have gained traction in recent years with solar cell performance of over 11% power conversion efficiency (PCE) recently demonstrated. The n-type polymer PNDIT2, also known as N2200 or P(NDI2OD-T2), has been extensively used for both photovoltaic as well as field-effect transistor applications. When paired with donor materials that have appropriately aligned energy-levels, PNDIT2 has exhibited device efficiencies over 10% PCE, and organic field effect transistors fabricated with PNDIT2 exhibit mobilities over 1 cm2/Vs. Thionation of the NDI moiety, which is the substitution of imide oxygen with sulfur atoms, has been shown to improve the field-effect transistor performance of NDI-based small molecules. Applying this strategy to PNDIT2, we explored the effect that thionation, in a 2S-trans configuration, has on the performance of all-polymer solar cells fabricated with the donor polymer PTB7-Th. Solar cells were fabricated with the original polymer, PNDIT2, as a reference, and an optimized efficiency of 4.85% was achieved. As samples with 100% conversion to 2S-trans configuration could not be produced due to synthetic limitations, batches with increasing ratios of 1S to 2S-trans thionation (15:85, 7:93, and 5:95) were studied. Devices with thionated PNDIT2 exhibited a systematic lowering of photovoltaic parameters with increasing thionation, resulting in device efficiencies of just 0.84%, 0.62%, and 0.42% PCE. The lower performance of the thionated blends is attributed to poor π-π stacking order in the thionated PNDIT2 phase, resulting in lower electron mobilities and finer phase separation. Evidence in support of this conclusion is provided by grazing incidence wide-angle X-ray scattering, transmission electron microscopy, photoluminescence quenching, transient photocurrent analysis, and SCLC measurements.
关键词： π-π stacking,PNDIT2,Thionation,All-polymer solar cells,Power conversion efficiency
更新于2025-10-22 19:40:53
-
Scaling behavior in on-chip field-amplified sample stacking
摘要： Field amplified sample stacking (FASS) uses differential electrophoretic velocity of analyte ions in the high-conductivity background electrolyte zone and low-conductivity sample zone for increasing the analyte concentration. The stacking rate of analyte ions in FASS is limited by molecular diffusion and convective dispersion due to non-uniform electroosmotic flow (EOF). We present a theoretical scaling analysis of stacking dynamics in FASS and its validation with a large set of on-chip sample stacking experiments and numerical simulations. Through scaling analysis, we have identified two stacking regimes that are relevant for on-chip FASS, depending upon whether the broadening of the stacked peak is dominated by axial diffusion or convective dispersion. We show that these two regimes are characterized by distinct length and time scales, based on which we obtain simplified non-dimensional relations for the temporal growth of peak concentration and width in FASS. We first verify the theoretical scaling behavior in diffusion and convection dominated regimes using numerical simulations. Thereafter, we show that the experimental data of temporal growth of peak concentration and width at varying electric fields, conductivity gradients, and EOF exhibit the theoretically predicted scaling behavior. The scaling behavior described in this work provides insights into the effect of varying experimental parameters, such as electric field, conductivity gradient, electroosmotic mobility, and electrophoretic mobility of the analyte on the dynamics of on-chip FASS.
关键词： dispersion,scaling analysis,on-chip electrophoresis,field-amplified sample stacking
更新于2025-09-23 15:23:52
-
Computational and experimental data on electrostatic density and stacking tendency of asymmetric cyanine 5 dyes
摘要： Far-red dyes such as cyanine 5 (Cy5) are gaining interest in (bio) medical diagnostics as they have promising features in terms of stability and brightness. Here, the electrostatic density and stacking tendency in different solvents of nine systematically altered asymmetrical Cy5 dyes are reported. In addition to this, the influence of molecular alterations on the vibronic coupling was reported. The data presented supplement to the recent study “The influence of systematic structure alterations on the photophysical properties and conjugation characteristics of asymmetric cyanine 5 dyes” (Spa et al., 2018).
关键词： Cyanine,Electrostatic density,Fluorescence,Stacking
更新于2025-09-23 15:23:52
-
A 5500-frames/s 85-GOPS/W 3-D Stacked BSI Vision Chip Based on Parallel In-Focal-Plane Acquisition and Processing
摘要： This paper presents a 3-D stacked vision chip featuring in-focal-plane read-out tightly coupled with flexible computing architecture for configurable high-speed image analysis. The chip architecture is based on a scalable standalone structure integrating image sensor on the top tier and processing elements (PEs) plus memories in the bottom tier. By using 3-D stacking partitioning, our prototype benefits from backside illuminated pixels sensitivity, a fully parallel communication between image sensor and PEs for low-latency performances, while leaving enough room in the bottom tier to embed advanced computing features. One scalable structure embeds a 16 × 16 pixel array (or 64 × 64 pixels in high-resolution mode), associated with an 8-bit single instruction multiple data (SIMD) processor; fabricated in dual 130-nm 1P6M CMOS process. This paper exhibits a 5500 frames/s and 85 giga operations per second (GOPS)/W in low-resolution mode, with large kernels capabilities through eight directions interpixel communication. Multiflow capability is also demonstrated to execute different programs in different areas of the vision chip.
关键词： parallel computing,imager,3-D stacking,vision chip
更新于2025-09-23 15:22:29
-
Time-order Phonon Scattering Processes are Responsible for the Asymmetric G* Raman Band in Graphene
摘要： Background: While most of the prominent features in the Raman spectrum of graphene are well understood as mentioned in patents within the Double Resonance (DR) picture, the origin of the peak at 2450 cm-1 (also called the G* band) still remains unclear. Method and Objective: In this work, we performed detailed Raman studies of single- and few-layer graphene using multiple laser excitations to unravel the origin of G* band. Results: Based on our analyses, we conclude that the G* band arises from a combination of Transverse Optical (iTO) and Longitudinal Acoustic (LA) phonons, and exhibits an asymmetric peak structure due to the presence of two different time-order phonon processes. The lower (higher) frequency sub-peak is ascribed to an LA-first (iTO-first) process. We provide three strong experimental evidences for the time-ordered scattering processes: the dependence of the G* band sub-peaks with (i) increasing laser energy, (ii) increasing defects, and (iii) increasing temperature. Finally, we attribute the enhanced asymmetry of the G* band in multi-layer graphene to multiple processes between electronic sub-bands, similar to the G’ band in multi-layer graphene. Conclusion: Our study uncovered the origin and nature of the G* peak in the Raman spectrum of graphene. We believe our results have important implications for processes such as graphene-enhanced Raman scattering, where the time-ordered scattering of optical and acoustic phonons can be very useful for sensing analytes.
关键词： second order,layer stacking,G* band,defects,graphene,Raman spectroscopy
更新于2025-09-23 15:22:29
-
[IEEE 2018 International Wafer Level Packaging Conference (IWLPC) - San Jose, CA, USA (2018.10.23-2018.10.25)] 2018 International Wafer Level Packaging Conference (IWLPC) - Enabling Reliability of 3D TSV Advanced Packages with Nonconductive, Pre-Applied Underfill Film Materials
摘要： Consumer and industry demand for high-performance computing, networking and graphics processing are pushing the limits of semiconductor packaging technology to support high-density integration, greater functionality and more complex device architectures in increasingly smaller form factors. To address these requirements, the packaging advanced is packaging technologies such as 3D stacking of IC chips, vertically connected by through silicon vias (TSVs). Advanced memory manufacturers are already integrating 3D TSV-based chip stacking processes using thermal compression bonding (TCB) the next-generation of memory devices for high bandwidth applications. These dense packaging architectures require materials that enable robust wafer processing and deliver long-term reliability. Moreover, for die thicknesses less than 100 μm, existing non-conductive paste (NCP) materials pose several challenges for thermal compression bonding due to potential die top and bonding tool contamination. Packaging specialists have moved toward the use of non-conductive film (NCF) for die structures – including TSV and Cu pillars – where more controlled flow, precise fillet formation and contamination prevention are essential. In this paper, the latest-generation of NCF materials and corresponding film lamination, base tape removal, die singulation, and thermal compression bonding process will be discussed. The new NCF formulation provides rapid curing kinetics to enable shorter bonding times and, therefore, higher UPH by delivering a three-second bonding profile, as well as feasibility for a two-second bonding profile. Combined with the embedded flux system and flow properties optimization, curing kinetics optimization, the novel NCF material achieves proper solder joint formation, no material entrapment, and void-free filling. Bonding force study of this NCF material was carried out on a die to substrate test vehicle to find out the optimal bonding force. And the reliability testing results will also be discussed. Based on the study outcomes, the new NCF material is expected to show excellent performance for thermal compression bonding for 3D chip-stacking applications.
关键词： UPH,thin die,NCF,3D TSV,chip-stacking
更新于2025-09-23 15:22:29
-
Fine-Tuning Aromatic Stacking and Single-Crystal Photoluminescence through Coordination Chemistry
摘要： Organic aromatics usually show a decrease in fluorescence efficiency in the solid state on account of well-known aggregation induced quenching. We have found that single crystals of coordination polymers consisting of γ-aminobutyric acid functionalized naphthalenediimide ligand (H2GABA-NDI) can give rise to highly emissive, broad, and red-shifted photoluminescence (PL) in the solid state. To better understand the origin of the bandwidth broadening with the π–π stacking distances, we performed time-resolved PL studies in a series of polymers with a variety of metal centers. We conclude that the broad steady-state PL signals is originated from a superposition of two emissive states with differing energy and lifetimes, with the lower energy one produced by the interchromophoric interactions mediated by π–π stacking of neighboring NDI units. Our work demonstrates that coordination chemistry is an effective tool to modulate interchromophoric couplings and that simple PL analysis can be used as a measure of the degree of π-stacking.
关键词： crystal engineering,luminescence,photochemistry,stacking interactions,coordination modes
更新于2025-09-23 15:22:29
-
Weighted Manifold Alignment using Wave Kernel Signatures for Aligning Medical image Datasets
摘要： Manifold alignment (MA) is a technique to map many high-dimensional datasets to one shared low-dimensional space. Here we develop a pipeline for using MA to reconstruct high-resolution medical images. We present two key contributions. Firstly, we develop a novel MA scheme in which each high-dimensional dataset can be differently weighted preventing noisier or less informative data from corrupting the aligned embedding. We find that this generalisation improves performance in our experiments in both supervised and unsupervised MA problems. Secondly, we use the wave kernel signature as a graph descriptor for the unsupervised MA case finding that it significantly outperforms the current state-of-the-art methods and provides higher quality reconstructed magnetic resonance volumes than existing methods.
关键词： Slice stacking,Wave kernel signature,Magnetic resonance imaging,Manifold alignment,Graph descriptor
更新于2025-09-23 15:22:29
-
Stacking effect on electronic, photocatalytic and optical properties: A comparison between bilayer and monolayer SnS
摘要： In this work, the stacking-dependent optoelectronic performances of a bilayer SnS were explored based on density functional theory (DFT). The results demonstrated that an AB-stacking induces an indirect-to-direct transition, a feature that is capable of vanquishing electron transition impediment from an intrinsic indirect monolayer SnS. An anisotropic and small carrier effective mass exists in all the stacking models, among which the AB-stacking with the lowest value favors high carrier mobility. Calculated band alignments are indicative of acceptable and adjustable photocatalytic activity for all the stacking models, unlike the monolayer SnS. The AB-stacking configuration possesses the strongest redox power, which facilitates it to be a potential candidate for photocatalytic water splitting. Additionally, the AB-stacking does effectively improve optoelectronic properties. The study demonstrated that layer-stacking is an availably adjustable method in the fields of sunlight-driven photocatalysis for nano-optoelectronic devices.
关键词： Electronic properties,Density functional theory,Stacking models,Optical properties,Photocatalytic properties
更新于2025-09-23 15:21:21
-
[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - A Non Local Multifocus Image Fusion Scheme for Dynamic Scenes
摘要： In order to overcome the limited depth of field of usual photographic devices, a common approach is multi-focus image fusion (MFIF). From a stack of images acquired with different focus settings, these methods aim at fusing the content of the images of the stack to produce a final image that is sharp everywhere. Such methods can be very efficient, but when a global geometrical alignment of images is out-of-reach, or when some objects are moving, the final image shows ghosts or other artefacts. In this paper, we propose a generic method to overcome these limitations. We first select a reference image, and then, for each image of the stack, reconstruct an image that shares the geometry of the reference and the sharpness content of the image at hand. The reconstruction is achieved thanks to a specially crafted modification of the PatchMatch algorithm, adapted to blurred images, and to a dedicated postprocessing for correcting reconstruction errors. Then, from the new image stack, MFIF is performed to produce a sharp result. We show the efficiency of the result on a database of challenging cases of hand-held shots containing moving objects.
关键词： focus stacking,computational photography,PatchMatch,non-local methods,Multifocus image fusion
更新于2025-09-23 15:21:21