bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of Charge Transfer Donor-Acceptor Co-Crystals with Long Lived Charge Carriers
Authors: Shivanna Mohana , Abou Taka Ali , Schrader Paul E , Ramasesha Krupa , Allendorf Mark , McCaslin Laura M , Stavila Vitalie 
Published: August 2024

Organic donor-acceptor co-crystals with long exciton lifetimes have emerged as a promising class of semiconductors for their unique photophysical properties. These are crystalline, single-phase materials composed of two or more different compounds in a stoichiometric ratio, providing a platform for unveiling the structure–property relationships at a molecular level. Importantly, co-crystals that are packed through π stacking interactions have the ability to form charge transfer (CT) excitons within donor-acceptor pairs.1,2,3 We hypothesize that co-crystals with a high degree of CT will have longer exciton lifetimes. Therefore, we design and synthesized of new co-crystals using derivatives of N,N-bis(3-pentyl)-perylene-3,4:9,10-bis(dicarboximide) (PDI, acceptor) with a series of donor molecules, including peri-xanthenoxanthene (PXX), perylene, and triphenylene. High quality single crystals were isolated by slow evaporation at room temperature from suitable solvent mixtures. Their crystal structures were successfully refined by single-crystal X-ray diffraction and the phase purity was validated by powder diffraction. Crystal structures revealed that the driving force for forming these co-crystals is π...π stacking. We measured diffuse reflectance UV/visible spectra of each of these co-crystals and compared with computed spectra to assign the observed electronic transitions. DFT calculations provide additional insights into the nature of the excited state CT interactions which can be derived from ground state electronic structure calculations. Transient absorption measurements were conducted to understand their long exciton lifetime for each of as synthesized co-crystals. We conclude that this study supported our previous hypothesis and such materials are potentially useful in applications ranging from photovoltaics and opto-electronics to photocatalysis.

References

1) A. Abou Taka, J. E. Reynolds Iii, N. C. Cole-Filipiak, M. Shivanna, C. J. Yu, P. L. Feng, et al. Phys.
Chem. Chem. Phys. 2023, 25, 27065.
2) L. Sun, Y. Wang, F. Yang, X. Zhang and W. Hu. Adv. Mater.
2019, 31, 1902328.
3) I. Schlesinger, N. E. Powers-Riggs, J. L. Logsdon, Y. Qi, S. A. Miller, R. Tempelaar, et al.
Chem.

Sci.,
2020, 11, 9532–9541.
(Invited) Sustainable and Non-Toxic Hydrogel-Based Dye-Sensitized Solar Cell: Performance Evaluation Under Indoor Illumination
Authors: Domenici Sara , Speranza Roberto , Bella Federico , Gatti Teresa , Lamberti Andrea 
Published: August 2024

Indoor photovoltaics have gathered growing interest amongst researchers, as a mean to exploit the indoor lighting we use in our daily life to power small devices. Dye-sensitized solar cells (DSSCs) represent good candidates for such applications[1]. However, when it comes to indoor applications, there is an increased demand for non-toxic and non-flammable solvents for electrolytes. The implementation of water-based electrolytes is a promising way to address these issues, whilst also ensuring the eco-friendliness and sustainability of these devices[2]. In this work, aqueous gel electrolytes incorporating a iodide/triiodide redox couple were made with a bio-sourced polymer, xanthan gum[3]. DSSCs were assembled using screen-printed TiO2 semiconducting layers treated with TiCl4 and sensitized with an organic dye, D131. As counter electrode, Pt sputtered FTO was used. The performance of the cells was investigated under indoor light intensities between 500 and 1000 lux.
[1]: Jilakian, M., & Ghaddar, T. H. (2022). Eco-Friendly Aqueous Dye-Sensitized Solar Cell with a Copper (I/II) Electrolyte System: Efficient Performance under Ambient Light Conditions. ACS Applied Energy Materials, 5(1), 257-265.
[2]: Bella, F., Gerbaldi, C., Barolo, C., & Grätzel, M. (2015). Aqueous dye-sensitized solar cells. Chemical Society Reviews, 44(11), 3431-3473.
[3]: Galliano, S., Bella, F., Bonomo, M., Viscardi, G., Gerbaldi, C., Boschloo, G., & Barolo, C. (2020). Hydrogel electrolytes based on xanthan gum: green route towards stable dye-sensitized solar cells. Nanomaterials, 10(8), 1585.
Trap Assessment and Mobility Simulation of Amorphous Indium Gallium Zinc Oxide Thin Film Transistors
Authors: Mattsson Måns Johannes , Parker Jared , Wager John F , Graham Matt Werden 
Published: August 2024

Ultra-broadband photoconduction (UBPC) is used to measure the sub-gap trap density of amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) across the bandgap, from the valence band mobility edge to within 0.15 eV (~6kBT) of the conduction band mobility edge. Figure (a) is a plot of the total integrated trap density (Ntraps, green) and the sub-gap density of states (dNtraps/dE, blue) as measured by UBPC for traps located just below the conduction band mobility edge (E-EC = 0). Three Gaussian sub-gap states are observed with peak energies of 0.9, 0.7, and 0.4 eV below the conduction band mobility edge. Note that the width of the 0.4 eV peak (180 meV) is much larger than that of the other two deeper peaks (45 meV). All three of these peaks are likely associated with oxygen vacancies, but it is unclear why the 0.4 eV trap is so much broader than all the other deeper oxygen vacancy derived donor trap states.
The black dotted curves included in Figure (b) are experimental EKV mobility (μEKV) versus overvoltage (VG-VON) plots obtained at three different temperatures (0 °, 20 °, and 100 °C). The red dashed curves are simulated mobility curves obtained assuming that only conduction band tail states act as electron traps to degrade the mobility. Since these red simulated curves grossly overestimate the experimental mobility, other traps must be operative in establishing the black experimental mobility curves. In fact, the inclusion of the 0.4 eV trap measured by UBPC in addition to the conduction band tail states in the simulation (blue curves) leads to excellent agreement between experimental and simulated mobility for all three temperatures (0 °, 20 °, and 100 °C). In summary, it is demonstrated how the mobility of a-IGZO can be simulated by including the experimentally observed DoS of a 0.4 eV centered Gaussian trap state.
References:
1. Mattson, G. W., Vogt, K. T., Wager, J. F., & Graham, M. W. (2023). Illuminating trap density trends in amorphous oxide semiconductors with ultrabroadband photoconduction. Advanced Functional Materials, 33(25). https://doi.org/10.1002/adfm.202300742
2. J.F. Wager (2022), “Amorphous semiconductor mobility physics & TFT modeling,” in Amorphous Oxide Semiconductors, Hosono, H., & Kumomi, H., (pp. 105–123), Wiley.

Figure 1
Spatial Nonuniformity of Photoresponse in SiC UV Avalanche Photodiodes Operating in Linear and Geiger Mode
Authors: Habersat Daniel B , Sampath Anand , Schuster Jonathan , Smith Jeremy , Derenge Michael , Garrett Gregory , VanMil Brenda , Wraback Michael , Bellotti Enrico , Zhu Mike , Ghandi Reza , Dolinsky Sergei , Aghayan Mehrnegar 
Published: August 2024

Silicon Carbide's intrinsic material properties, along with the availability of low-defect density, 6" substrates, make it an attractive material system for visible-blind ultraviolet (UV) detectors. Avalanche photodiodes (APDs) made from SiC have been shown to operate both as linear mode detectors with high gain (>10⁷) and as single-photon avalanche detectors (SPADs) with competitive photon detection efficiency. However, reported spatial non-uniformities in photoresponse of these devices will reduce sensitivity [1,2].
In this paper, we examine the impact of device geometry, epitaxial variations, and crystal anisotropy on the spatial uniformity of photoresponse in SiC APDs. Photoresponse maps are generated using a fast 285 nm pulsed LED source that is tightly focused to a ~10 µm spot. Response maps are measured for devices with different geometries fabricated on the same chip in both linear-mode and Geiger-mode. Measurements on standard pin diodes will be presented, along with separate absorption, charge, and multiplication (SACM) structures.
Experimental results indicate that all devices exhibit localized regions of high photoresponse at gain > 1000 and that the spreading of the photoresponse is highly directional. Finger diodes with 120 μm x 30 μm mesas exhibit good response uniformity with a variation < 30% across the device. In contrast, diodes with 60 and 90 μm square-shaped mesas exhibit similar uniform response spreading along one edge that is bounded by the size of the mesa, but a >10x drop in relative response over ~30-40 μm in the orthogonal direction which is much shorter than the extent of the mesa. Devices with 100 μm circular mesas exhibit somewhat similar results to the square diodes, but with the presence of multiple hot spots in response.
Experimental results are analyzed through 3D numerical modeling of devices which accounts for the effects of doping and thickness variations across the substrate as well as the anisotropy of impact ionization. Modeling indicates that small variations in the thickness in the drift regions of a diode can yield meaningful variations in avalanche gain across the mesa. The impact of anisotropic impact ionization will be considered using full-band 3D Monte Carlo calculations.

X. Bai, H.-D. Liu, D. C. McIntosh and J. C. Campbell, "High-Detectivity and High-Single-Photon-Detection-Efficiency 4H-SiC Avalanche Photodiodes," IEEE J. Quantum Electron. 45
300-303 (2009). DOI: 10.1109/JQE.2009.2013093.

L. Su et al, "Recent progress of SiC UV single photon counting avalanche photodiodes," J. Semicond.
40 121802 (2019). DOI: 10.1088/1674-4926/40/12/121802.

Figure 1
Electrochemical Weakening Material Strength for Accelerated Thinning of Silicon Carbide Substrates
Authors: Wu Chun-Huang , Li Shu-Cheng , Lin Yu-Tang , Chien Bill Po-Yen , Chiou Yu-Sheng , Huang Wei-Chi , Cheng Chao-Chia , Lee Benjamin T.-H. 
Published: August 2024

This paper presents a novel approach to expedite the thinning of silicon carbide (SiC) substrates, a crucial step in enhancing material performance and extending chip longevity by reducing volume resistivity. The traditional methods of SiC substrate thinning, such as diamond wheel grinding and plasma etching, have inherent limitations, including the risk of wafer breakage and high processing costs. In response to these challenges, we propose an innovative technique involving the electrochemical etching attenuation of SiC strength, offering a cost-effective and efficient solution.
In this study, we employed an electrochemical method to initially weaken the SiC substrate from the surface to a defined depth, followed by fine-tuning its thickness using a conventional diamond grinding wheel. Remarkably, our results demonstrate that SiC substrates subjected to electrochemical treatment exhibit well-structured lattices free from residual stresses. This novel approach not only reduces the risk of wafer breakage but also enhances the material's integrity (Figure 1).
To gain deeper insights into the effects of electrochemistry on SiC material strength, advanced characterization techniques, including scanning electron microscopy, were employed. Our findings reveal that the electrochemically treated SiC surface exhibits a sponge-like morphology, with a cross-sectional profile showcasing prominent columnar structures (Figure 2). This sponge-like structure is attributed to the removal of silicon atoms during anodization, affirming the effectiveness of electrochemical methods in rapidly attenuating the material strength of SiC substrates, thereby facilitating their efficient thinning through grinding without compromising substrate integrity.
In summary, this research highlights the potential of electrochemical methodologies for the initial weakening of SiC substrates, leading to accelerated and cost-effective thinning processes. This breakthrough not only expedites SiC substrate thinning but also contributes significantly to the advancement of SiC substrate thinning and grinding techniques, promising substantial benefits for future semiconductor device fabrication.

Figure 1
Developing Field Effect Transistor Sensors Based on DNA Probes to Detect Staphylococcus Lugdunensis Bacteria
Authors: Thokchom Rohan , Su Yi-De , Tseng Huan-Wei , Kalaimani Vishal Mani , Lin Chia Kai , Zeng Guan-Cheng , Wang Yu-Lin 
Published: August 2024

The goal of this research is to work with an Electrical Double Layer (EDL)-gated Field Effect Transistor (FET) to detect the bacteria Staphylococcus lugdunensis, which can cause a variety of illnesses, including infections of the skin and soft tissues. In rare cases, Staphylococcus lugdunensis can be successfully identified using the combination of a positive catalase test, a negative tube coagulase test, a positive PYR test, and a positive ornithine decarboxylase test. We are employing an Electrical Double
Layer (EDL)-gated Field Effect Transistor (FET) to speed up the procedure because this test is time consuming and requires a highly competent individual to perform. An ssDNA probe was developed, and effectively immobilized on a gold surface electrode sensor with a square surface, and due to hybridization with the cDNA at different concentrations, electrical signals were generated in the form of current.
Our sensor was fabricated using photolithography where the gold electrode surface having 500 μm x 500 μm gate sensing area consisting of each individually addressable sensor arranged in a 1 x 8 array which is the extent gate was expose for immobilization purpose. The sensor was then subjected
to O2 plasma & HCl solution for surface cleaning and fluorescence image of baregold were taken Figure1(b).
The Single-Stranded DNA comprising of fluorescent dye (FAM) at 3’ and thiol modifier at 5’ was drop-casted on the gold surface and was incubated for 24 hours at 24°C. After, it went through a washing process in order to remove the unbound ssDNA and fluorescence images were taken. We observed that intensity was higher than that of baregold which indicates that our probe has successfully immobilized on the gold surface Figure 1(b).
Figure 1(a) represents the device that we designed. The system works with N-Channel Enhancement-Mode DMOS FET (VN10LP) in which a continuous drain voltage (3.5 V) was applied and the drain current which is the signal, were measured at two distinct gate bias voltage (2V and 3V). cDNA having quencher (BHQ1) at 5’ was diluted in different concentration namely 1fM, 10fM, 100fM and 1000fM. These cDNA with different concentrations were drop-casted on our sensor with Tris-EDTA (TE) buffer as the baseline and starting with lower concentration to higher concentration every after 12 seconds periodically where we record the change in signal as shown in Figure 1(c).
After the electrical measurement, fluorescence image was taken and we can observe that it quenched which indicates that the cDNA and the immobilized ssDNA has successfully hybridized which give the signal change.

Figure 1: (a) Surface Immobilization Principal Display in Extended Gate EDL BioFETs. (b)
Fluorescence value comparison. (c) Plot showing the change in drain current over time for aptamer
sensors exposed to various cDNA concentrations.

Figure 1
Exploring Neuromorphic Computing with Double-Gate Floating Device Based on Van Der Waals Heterostructures
Authors: Ghosh Advaita , Lin Yen-Fu , Lin Shu-Ping 
Published: August 2024

Neuromorphic devices represent a frontier in technological development, aiming to emulate the intricate parallel functionalities inherent to the human brain [1, 2]. Traditional computing models, such as Von Neumann architecture, grapple with limitations in parallel processing, prompting the exploration of neuromorphic computing to integrate memory and processing efficiently. Our research presents the double gate floating device based on Vander Waals heterostructure (DG-VH-FET), employing molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN), and graphene (Gr) as key components. These devices, based on 2D materials, enable independent modulation of channel doping through electrostatic means [3].
In this study, we initially assessed the fundamental characteristics of the floating gate, including transfer characteristics, output characteristics, retention, and endurance. By applying constant drain-to-source voltages (VDS) while introducing variations in the back gate voltage (VBG) sweeping range, the memory window of the transfer characteristics changes. Conversely, maintaining a constant VBG and VDS while varying the top gate voltage (VTG) solely results in a shift in the threshold voltage of the memory window. This is attributed to the crucial role of VBG in charge trapping in the floating gate layer, with the influence of VTG on charge trapping being negligible due to the screening effect of MoS2 [4]. Moreover, by using VTG and VBG this study shows that DG-VH-FET could have potential applications in exploring and understanding various neurological effects, thereby bridging the gap between electronics and biology.

Figure 1
Detection of Hydrogen Ions Resulting from the Inhibition of Acetylcholinesterase Using Indium Tin Oxide-Coated Nanostructures for Pesticide Sensing
Authors: Zeng Yi-Syuan , Wei Yu-Ting , Chao Yu-Chan , Lin Shu-Ping 
Published: August 2024

The neurotransmitter acetylcholine (ACh) is hydrolyzed by acetylcholinesterase (AChE) into acetic acid and choline to terminate synaptic transmission (1). Organophosphorus (OPs) found in pesticides induce toxicity in organisms by irreversibly binding to AChE, leading to the phosphorylation of the serine residue at the active site. ACh cannot undergo hydrolysis by the phosphorylated enzyme, resulting in excessive stimulation of nerves and muscles, akin to a nerve agent (2). Our objective is to develop a rapid detection tool for determining the levels of pesticide residues in dairy products. In this study, we measured the release of hydrogen ions (H+) resulting from the hydrolysis of ACh by AChE, serving as an indirect method to evaluate the inhibitory effect of OPs on AChE. To detect the signals of H+ released during ACh decomposition, we used ITO-coated nanostructures modified with 3-aminopropyl trimethoxysilane (APTMS) as a sensing substrate integrated into the extended gate of a field-effect transistor (EGFET) biosensor. The amino group at the end of APTMS can bond with H+. By monitoring the changes in electrical signal from the EGFET biosensor, it is possible to know the concentration of H+ in the solution. The output characteristics (Id-Vd) of the APTMS-modified ITO-VASiNW EGFET were measured using ACh solutions at different concentrations. A correlation was observed between Id and ACh concentration within the tested range, exhibiting a sensitivity of 0.016 mA1/2 / mM and an R2 value of 0.9. A lower concentration of H+ indicates a more pronounced inhibitory effect on AChE by OPs and suggests higher levels of pesticide residues.

References

(1) Colović, M. B., Krstić, D. Z., Lazarević-Pašti, T. D., Bondžić, A. M., & Vasić, V. M. (2013). Acetylcholinesterase inhibitors: pharmacology and toxicology. Curr Neuropharmacol, 11(3), 315-335.
(2) Rajagopalan, V., Venkataraman, S., Rajendran, D. S., Vinoth Kumar, V., Kumar, V. V., & Rangasamy, G. (2023). Acetylcholinesterase biosensors for electrochemical detection of neurotoxic pesticides and acetylcholine neurotransmitter: A literature review. Environmental Research, 227, 115724.

Figure 1
Understanding Mechanisms and Reversibility of Anode Degradation in PEM Water Electrolysis
Authors: Blair Sarah J. , Alia Shaun M , Padgett Elliot 
Published: August 2024

Water electrolysis is an important route toward sustainable industrial production of hydrogen, as well as mitigation of the CO2 emissions associated with current hydrogen production from natural gas. The industrial deployment of clean electrolytic hydrogen will depend on long-term electrolyzer durability under the intermittent operating conditions associated with coupling with renewable sources of electricity. Thus, understanding cell degradation mechanisms is required to develop mitigation strategies and minimize performance degradation over extended periods of operation.
Here, we investigate the effect of temperature and intermittent conditions on proton exchange membrane (PEM) water electrolyzer performance over a variety of timescales. Performance losses consisting of both reversible losses and irreversible degradation accelerate quickly during holds at high current densities and low temperatures, reaching high cell voltages within several hours. However, the cell can be returned to near beginning-of-test performance by interrupting these current holds with a variety of intermittent states of operation, such as interruption of the applied current or operation at higher temperatures. Reversible losses can harm the overall cell efficiency without being captured in short-term polarization curves, and may also contribute to stressors causing long-term degradation. The impact of different shut-down and idle states on the catalyst layers and cell degradation will also be discussed. The presented insights could contribute to the development of accelerated stress test protocols as well as performance recovery strategies for long-term operation of PEM water electrolyzers.
(Invited) Electron Microscopy Investigation of PEM Electrolyzer Degradation at Low Iridium Loadings
Authors: Yu Haoran , Cullen David A. , Serov Alexey , Chan Ai-Lin , Padgett Elliot , Alia Shaun M , Parrish Chance , Mauger Scott A , Li Kui , Komini Babu Siddharth , Myers Deborah J. , Mukundan Rangachary 
Published: August 2024

The employment of hydrogen as an energy carrier provides a promising solution toward zero carbon emission and battling climate change. To meet the DOE’s Hydrogen Shot goal of $1 per kilogram of hydrogen by 2031, proton exchange membrane (PEM) water electrolysis is a key technology of hydrogen production from renewable energy sources. Successful deployment of PEM electrolyzers requires reducing cost while simultaneously improving performance and lifetime. While cost reduction is expected from a variety of strategies including scaling up, operation optimization, and advanced manufacturing, it remains vital to reduce the use of noble-metal catalyst due to its scarcity and vulnerable supply chain subject to market disturbance. [1]
Reducing the loading of iridium catalyst on the anode while maintaining electrolyzer performance and durability is of great challenge. In this talk, we discuss issues in PEM electrolyzer component development and advanced manufacturing of electrode layers related to catalyst loading reduction with an emphasize on analytical electron microscopy which provides valuable insight on materials morphology, crystalline structure, and chemical compositions. The batch-to-batch variance of catalyst morphology and elemental composition/distribution from commercial suppliers will be examined for catalyst down-selection. We then analyze the effect of reducing Ir loading on the electrode layer structure and ionomer distribution. These results are correlated with electrochemical measurements in the electrolyzer cell, which help elucidate the effect of low catalyst loading on electrolyzer performance. Morphologies of degraded low-loading anode catalyst layer and gas recombination layers will be investigated, and the dissolution and migration of iridium will be studied. We will also examine impact of different roll-to-roll manufacturing strategies for low-loading catalyst layers and on electrolyzer durability. Last but not least, we analyze MEAs subject to cation contamination and recovery procedure with electron microscopy. [2]
References
[1] Alia, S.M., Current Opinion in Chemical Engineering 2021, 33:100703.
[2] Funding for this work was provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office through the H2NEW Consortium. Electron microscopy research conducted as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.