Selective Charge Carrier Transport and Bipolar Conduction in an Inorganic/Organic Bulk-Phase Composite: Optimization for Low-Temperature Thermoelectric Performance

Abundant conducting polymers are promising organic substances for low-temperature thermoelectric applications due to their inherently low thermal conductivities. By introducing a conducting polymer filler (PEDOT:PSS─poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid)) into a representative inorganic thermoelectric matrix (Bi2Te3), a bulk-phase composite (i.e., inorganic matrix/organic filler) for low-temperature thermoelectric applications is proposed. This composite hosts an interfacial energy barrier between the inorganic and organic components, facilitating controlled carrier transport based on its energy level, known as the energy filtering effect, and thus the composite exhibits a highly improved Seebeck coefficient compared to pristine Bi2Te3. The composite also displays a completely different temperature dependence on the Seebeck coefficient from Bi2Te3 due to its distinct bipolar conduction tendency. By regulation of the energy filtering effect and bipolar conduction tendency, the composite undergoes noticeable variations in the Seebeck coefficient, resulting in a significantly enhanced power factor. Furthermore, the composite shows a substantially reduced thermal conductivity compared to Bi2Te3 because it has lower carrier/lattice thermal contributions, possibly attributed to its high carrier/phonon scattering probabilities. Owing to the superior power factor and reduced thermal conductivity, the composite exhibits markedly enhanced thermoelectric performance, achieving a maximum figure of merit of approximately 1.26 at 380 K and an average figure of merit of approximately 1.23 in the temperature range of 323-423 K. The performance of the composite is competitive with previously reported n-type Bi2Te3 binary or ternary analogues. Therefore, the composite is highly expected to be a promising n-type counterpart of p-type Bi2Te3-based alloys for various low-temperature thermoelectric applications. © 2023 The Authors. Published by American Chemical Society.FALS

Pushing the Resolution Limit of Stimulated Emission Depletion Optical Nanoscopy

Optical nanoscopy, also known as super-resolution optical microscopy, has provided scientists with the means to surpass the diffraction limit of light microscopy and attain new insights into nanoscopic structures and processes that were previously inaccessible. In recent decades, numerous studies have endeavored to enhance super-resolution microscopy in terms of its spatial (lateral) resolution, axial resolution, and temporal resolution. In this review, we discuss recent efforts to push the resolution limit of stimulated emission depletion (STED) optical nanoscopy across multiple dimensions, including lateral resolution, axial resolution, temporal resolution, and labeling precision. We introduce promising techniques and methodologies building on the STED concept that have emerged in the field, such as MINSTED, isotropic STED, and event-triggered STED, and evaluate their respective strengths and limitations. Moreover, we discuss trade-off relationships that exist in far-field optical microscopy and how they come about in STED optical nanoscopy. By examining the latest developments addressing these aspects, we aim to provide an updated overview of the current state of STED nanoscopy and its potential for future research. © 2023 by the authors.TRU

ELECTRONIC DEVICE AND CONTROLLING METHOD OF ELECTRONIC DEVICE

전자 장치 및 전자 장치의 제어 방법이 개시된다. 구체적으로, 본 개시에 따른 전자 장치는 전자 장치의 부하에 대한 정보를 획득하고, 부하에 대한 정보를 바탕으로 적어도 하나의 어플리케이션에 대한 목표 지연 시간을 결정하며, 기 정의된 복수의 전력 상태 및 복수의 인터럽트 발생 속도의 조합들 중 목표 지연 시간을 만족하는 적어도 하나의 조합을 식별하고, 적어도 하나의 조합들 중 에너지 소모량이 가장 적은 하나의 조합을 식별하며, 식별된 하나의 조합에 따른 전력 상태 및 인터럽트 발생 속도를 바탕으로 전자 장치를 제어한다

Acidic CO2 Electroreduction for High CO2 Utilization: Catalysts, Electrodes, and Electrolyzers

The electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) is considered a promising technology for converting atmospheric CO2 into value-added compounds by utilizing renewable energy. The CO2RR has developed in various ways over the past few decades, including product selectivity, current density, and catalytic stability. However, its commercialization is still unsuitable in terms of economic feasibility. One of the major challenges in its commercialization is the low single-pass conversion efficiency (SPCE) of CO2, which is primarily caused by the formation of carbonate (CO32−) in neutral and alkaline electrolytes. Notably, the majority of CO2RRs take place in such media, necessitating significant energy input for CO2 regeneration. Therefore, performing the CO2RR under conditions that minimize CO32− formation to suppress reactant and electrolyte ion loss is regarded an optimal strategy for practical applications. Here, we introduce the recent progress and perspectives in the electrochemical CO2RR in acidic electrolytes, which receives great attention because of the inhibition of CO32− formation. This includes the categories of nanoscale catalytic design, microscale microenvironmental effects, and bulk scale applications in electrolyzers for zero carbon loss reactions. Additionally, we offer insights into the issue of limited catalytic durability, a notable drawback under acidic conditions and propose guidelines for further development of the acidic CO2RR. © 2024 The Royal Society of Chemistry.FALS

Soft, conformal PDMS-based ECoG electrode array for long-term in vivo applications

Electrocorticogram (ECoG) electrode arrays based on soft materials, such as polydimethylsiloxane (PDMS), are preferable because they can be implanted with better conformal contact and have physical properties close to biological tissues; thus, the adverse effects on tissues are minimal. However, the realization of electrodes in the micrometer scale on PDMS is challenging. Previously, parylene-treated PDMS was suggested as a solution and proven to be successful in acute in vivo applications. In this study, PDMS-based ECoG electrode arrays fabricated using parylene-treated PDMS (parylene-deposited PDMS and parylene-filled PDMS) are evaluated for the first time in terms of stability and reliability for long-term use. The mechanical and electrochemical properties are investigated over time for up to 8 months through accelerated aging. The ECoG electrode array, implanted in the primary somatosensory area of the brain, can successfully record somatosensory evoked potentials (SEPs) upon mechanical stimulus of the paws with sufficient spatial resolution to distinguish between forepaw and hindpaw stimulations. Finally, the PDMS-based electrodes demonstrate the feasibility of chronic recording for up to 3 months in non-human primates. Based on theses results, it is concluded that they can be used as promising materials and methods to develop various bio-integrated electronic devices that require softness, flexibility, conformability, and robustness over long-term. © 2023 The AuthorsTRU

A road map for the treatment of pediatric diffuse midline glioma

Recent clinical trials for H3K27-altered diffuse midline gliomas (DMGs) have shown much promise. We present a consensus roadmap and identify three major barriers: (1) refinement of experimental models to include immune and brain-specific components; (2) collaboration among researchers, clinicians, and industry to integrate patient-derived data through sharing, transparency, and regulatory considerations; and (3) streamlining clinical efforts including biopsy, CNS-drug delivery, endpoint determination, and response monitoring. We highlight the importance of comprehensive collaboration to advance the understanding, diagnostics, and therapeutics for DMGs. © 2023 Elsevier Inc.FALS

Properties of Si-AlN Core-Shell Microcrystals by Al-Based Nanostructures

육방정계 (hexagonal) Si-AlN 코어-쉘 (core-shell) 마이크로 결정을 혼합소스 수소화물기상법에 의해 성장하였다. 특히 육방정계 Si-AlN 코어-쉘 마이크로 결정은 Al 기반 나노구조 (Al-based nanostructure)를 기반으로 성장되는 것을 발견하였다. 육방정계 Si은 준 직접 밴드갭 (quasi-direct bandgap) 에너지를 가지며 AlN 또한 육각형 우르자이트 (wurtzite) 구조를 가지므로 전력반도체 혹은 광전소자에 대한 새로운 기회를 열 수 있다. 본 논문에서 성장된 육방정계 Si-AlN 코어-쉘 마이크로 결정은 주사전자현미경 (FE-SEM), EDS, 및 HRTEM을 사용하여 그 특성을 확인하였으며 성장 메커니즘을 제시한다. 따라서 육방정계 Si-AlN 코어-쉘 마이크로 결정은 반도체 성장 방법의 새로운 예가 될 것으로 기대한다. Hexagonal Si-AlN core-shell microcrystals were grown by the mixed-source hydride vapor phase method. In particular, it was found that the hexagonal Si-AlN core-shell microcrystals were grown by the role of the Al-based nanostructure. Since hexagonal Si has a quasi-direct bandgap energy and AlN also has a hexagonal wurtzite structure, it can open up new opportunities for power semiconductors or optoelectronic devices. In this paper, the hexagonal Si-AlN core-shell microcrystals grown were characterized using scanning electron microscopy (FE-SEM), EDS and HRTEM, and the growth mechanism is presented. Therefore, the hexagonal Si-AlN core-shell microcrystal is expected to be an example of a new method in the field of semiconductor growth. © New Physics: Sae Mulli.TRU

Highly Deformable Double-Sided Neural Probe with All-in-One Electrode System for Real-Time In Vivo Detection of Dopamine for Parkinson's Disease

Precise monitoring of neurotransmitters, such as dopamine (DA), is critical for understanding brain function and treating neurological disorders since dysregulation of DA implicates in a range of disorders, including Parkinson's disease (PD), schizophrenia, and addiction. This study proposes a multi-deformable double-sided (MDD) DA-sensing probe with the three-electrode system in all-in-one form for reliable real-time monitoring of DA dynamics by integrating working, reference, and counter electrodes on a single probe. The proposed probe achieves high DA sensitivity and selectivity in virtue of enzyme immobilization on the 3D nanostructures grown on working electrode. Also, the serpentine design is employed for the electrodes to withstand in various deformations by achieving high stretchability and manage the stress induced on the probe. Experimental and computational analysis demonstrates an effective reduction in induced-stress on the electrodes. The MDD DA-sensing probe is implanted into the brain with success to enable real-time, in vivo monitoring of DA levels in rodents. Furthermore, DA dynamic changes are monitored before and after treatment with L-DOPA in hemi-PD mice. This extremely deformable implantable probe has the potential for use in the study and treatment of neurodegenerative diseases, providing reliable monitoring of DA dynamics with minimal damage to brain tissue. © 2023 Wiley-VCH GmbH.FALS

Exploring the deposition pathway in the notch region of double-graded bandgap ACIGS solar cells

The bandgap widening of Ag-alloyed Cu(In,Ga)Se2 (ACIGS) thin films poses a significant challenge in enhancing their photocurrent. This study demonstrates correlations between element diffusion behavior and notch-point formation in ACIGS films, which ultimately influence the resulting current circuit voltage and fill factor. Our findings delineate a novel approach for fabricating a suitably tailored band gap grading in ACIGS, which serves as a bottom subcell in tandem configuration. This was achieved by modulating a wide range of process temperatures from 340 to 470 °C, which were measured by pyrothermal, to assess the GGI profile during deposition. Experiments were undertaken to variate the second-stage conditions, striving to sustain the photocurrent, mitigate defects, and enhance crystallinity, achieving an impressive performance of 17.7 % without applying post-deposition treatments or anti-reflection coatings. The efficiencies surpassing 8 % were achieved as we measured these cells under a 715 nm long-pass filter, which corresponds to the bandgap of a typical top cell in tandem applications (1.73 eV photon energy). These results emphasize the significance of understanding the deposition temperature and its impact on the properties of ACIGS films, paving the way for further advancements in solar-cell technology. © 2023 Vietnam National University, HanoiTRU