bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Digital Presentation) Study of Structural and Ionic Conductivity Property in Gd3+ and Sm3+ Co-Doped Ceria for Low Temperature SOFC Electrolyte Application
Authors: Vinchhi Prerna , Vinchhi Prerna 
Published: February 2024

In recent years, fuel cells have become one of the most efficient and clean energy conversion devices. Due to their use in stationary as well as mobile power applications, they have also gained a lot of attention in this field. From all other fuel cells, SOFC has several advantages such as absence of liquid component, vibration free working, fuel and many more. However, two most crucial aspects of SOFC are operating temperature and the choice of electrolyte materials. It is the most efficient fuel cell with a setback in its elevated operating temperature, as high as around 800℃ -1000℃. To achieve high ionic conductivity in a SOFC, it is very important to tailor the electrolyte properties, simultaneously reducing the operating temperature.
Conventionally, Yttria Stabilized Zirconia (YSZ) has been the most studied electrolyte material with a limiting factor of its high operating temperature. Doped Ceria has been one of the most explored alternatives of YSZ, which not only reduces the operating temperature but also enhances the ionic efficiency due to its electro-catalytic property. The double valency property of CeO2 occurring due to oxygen non-stoichiometry (CeO2-δ), generates oxygen vacancies making it a potential electrolyte material. Rare Earth (RE) dopants like Gd3+ and Sm3+ have reported to have high ionic conductivity at low temperatures. In the present study, synthesis of Sm-Gd- co-doped CeO2 by wet chemical route to ensure homogenous distribution, with the stoichiometry Ce1-a Gda-y Smy O2-0.5δ where a=0.20 and 0≤y≤a. It was prepared by modified co-precipitation method wherein, no additional water has been utilized during the co-precipitation process in order to minimize the particle agglomeration. Phase pure particles were obtained by calcining the precipitants at 650℃ in air and the green body made from it were sintered in air at elevated temperature of 1450 °C to achieve high density pellet. XRD and Raman spectroscopy confirmed successful substitution of both dopants and presence of single-phase cubic structure of the nanoparticles. The surface morphology was studied using FESEM which showed highly dense structure with more than 97% density. The electrochemical impedance spectroscopy (EIS) of the sintered pellets in the temperature range of 400-700℃, showed much higher conductivity then singly doped Ceria .

Figure 1
Thin Membranes Using PFSA-Vinylon Intermediate Layer for PEM Fuel Cells
Authors: Kim Jedeok , Yamasaki Kazuya , Ishimoto Hitoshi 
Published: February 2024

Fuel cells are attracting attention as one of the key energy devices for achieving carbon neutrality in 2050. Currently, fuel cells are being improved for versatile mobile applications. Among the components of fuel cell devices, polymer electrolyte membranes for proton exchange, in particular, are required to have high proton conductivity at high temperature, high and low humidification, and thin membranes. Proton-exchange fuel cells utilize perfluorosulfonic acid (PFSA) ionomers and membranes from Chemours and 3M and Solvay [1]. Nafion membranes with a thickness of 178-25 μm and Gore select membranes (with reinforcement) with a thickness of 20-5 μm have been commercialized [2,3]. On the other hand, thinner polymer electrolyte membranes can reduce the ohmic voltage drop in fuel cells to improve performance and lower costs. However, it is difficult to obtain thin membranes of less than 20 μm without reinforcement using PFSA ionomers.
In this report, a thin PFSA electrolyte membrane (10 μm) without reinforcement was successfully developed by introducing a PFSA-vinilon composite layer as an intermediate layer of the PFSA membrane. The fuel cell evaluation revealed that it has a high current density.
The ionomers used were 5% Nafion solution (DE520 CS type, EW=1100) and 6% Aquivion solution (D83-06A, EW=830). PVA (polyvinyl alcohol) was synthesized from polyvinyl acetate (PVAc, Mw=100,000). The laminated membranes (10 μm thickness) was obtained by preparing a 2 μm PFSA layer, followed by a 6 μm PFSA-PVA composite layer, then a 2 μm PFSA layer was coated. Finally, laminated membranes with PFSA-Vinylon composite layers were obtained by Formalization reaction the PFSA-PVA composite layers.
FTIR evaluation of the PFSA/ PFSA-Viynylon/ PFSA multilayers confirmed the presence of an intermediate layer by observing Vinylon-derived peaks. Conductivities of about 4.5 mS/cm and 2.5 mS/cm in the thickness direction were obtained at 80°C, 90%RH and 20%RH, respectively. On the other hand, I-V evaluation was performed at 80°C, 100%RH and 35%RH using hydrogen, oxygen and air. Nafion 212 was used as a comparison membrane. The I-V characteristics of the laminated membranes showed higher current density than that of the Nafion membrane. Maximum current densities of 3 A/cm2 at 0.6 V and 3 A/cm2 at 0.4 V were obtained at 80°C, 100% RH and 35% RH with hydrogen and oxygen, respectively. Regarding the comparison of PFSA ionomers, Aquivion showed higher performance at higher current densities than Nafion [4].
References
[1] A. Kusoglu, A.Z. Weber, Chem. Rev.
2017, 117, 987–1104.
[2] J.A. Kolde, B. Bahar, M.S. Wilson, T.A. Zawodzinski, S. Gottesfeld, Electrochem. Soc. Proc.
1995, 95-23, 193–201.
[3] B. Kienitz, J.Kolde, S. Priester, C.Baczkowski, M. Crum, Electrochem. Soc. Trans.
2011, 41(1) 1521-1530.
[4] J. Kim, K. Yamazaki, H. Ishimoto, Y. Takata, Polymers, 2020, 12, 1730-1735.
Washable and Eco-Friendly PEDOT:PSS Coated Silk Yarn Based-Transpiration-Driven Electrokinetic Power Generator with Tremendous Energy Generation
Authors: Yoon Hyungsub , Hwang Byungil , Yun Tae Gwang 
Published: February 2024

Since the importance of eco-friendly technologies and environmental consideration has been increased gradually, energy harvesting technologies that generate electricity from ambient has been gained attentions, including a solar cell, a piezoelectric, a triboelectric, and a thermoelectric device. However, since the relative low energy generation efficiency has been considered as the obstacle, the research on a novel energy harvesting technology is necessary.
A transpiration driven-electrokinetic power generator (TEPG), one of the hydro-electric nanogenerators, has been developed recently and researched due to the abundant energy resource (water), the ability to generate energy continuously, no sensitivity to ambient condition, etc. The basic concept is based on the transpiration process where the water flows from roots to leaves by water gradient in the plants. The water gradient in TEPG system is formed with dropping water at one side of the device. There are two main components, including a conductive material and a hydrophilic substrate. The conductive materials with high surface area capture the cations in solution to decrease a surface energy, leading to formation of the electrical double layer. The hydrophilic substrate promotes the flow of solution along the substrate, leading to the transfer of electrons in the conductive material.
Herein, we utilize the PEDOT:PSS as conductive material and silk yarn as hydrophilic material. A silk yarn is a natural and biodegradable material with the high mechanical properties, lightweight, and biocompatibility. PEDOT:PSS is promising candidate for TEPG device because its negative charged PSS groups attract the cations selectively via electrostatic interaction, leading to the increase of potential difference between wet/dry region. However, the low washing resistance of PEDOT:PSS is the limitation for practical wearable devices since the cleanness is essential. During the cleaning process, the PEDOT:PSS is easily detached from the substrate. Therefore, the research on the PEDOT:PSS with sufficient water resistance is essential for its wider utilization. In general, an ethylene glycol (EG) is commonly used for improving water resistance of PEDOT:PSS through hydrogen bonding with PSS parts. However, it is also known as the agent to enhance electrical conductivity via removal of excess PSS. Thus, we introduce the divinyl sulfone (DVS) as a covalently cross-linker for enhancing washing resistance of PEDOT:PSS. In this work, we compare the energy generation performance and washing resistance of various PEDOT:PSS coated TEPGs without and with EG or DVS, named as PS-TEPG, PES-TEPG, and PDS-TEPG, respectively.
Nickel-Doped Cobalt Oxyhydroxide Nanowires Coupled Polyaniline Functionalizedcarbon Cloths As Multifunctional Electrocatalysts for Hydrogen/Oxygen Evolutionreactions at All pH Levels
Authors: Lingappan Niranjanmurthi , Lee Wonoh 
Published: February 2024

Hydrogen represents a carbon-free and sustainable energy carrier. Electrochemical water splitting via hydrogen
evolution reaction (HER) and oxygen evolution reaction (OER) is a green approach for the hydrogen production.
Nevertheless, unfavorable thermodynamics and sluggish kinetics limit the water splitting efficiency. While the
benchmark catalysts such as Pt@C and RuO2/C catalysts display remarkable catalytic activity, the inferior
durability remains a major concern. Further, scarcity and high demand result in sharp rise in cost, hindering their
large-scale commercialization. Herein we rationally design the synthesis of nickel-doped cobalt oxyhydroxide
nanowires grown on PANi functionalized CF (Ni@CoOOH@PANi-CF) as multi-functional electrocatalyst for HER
and OER. In this design, the interfacial PANi layers substantially improve the surface functionality of the CF
substrate and thereby facilitates strong coupling interaction with the Ni@CoOOH catalyst, which influences the
charge transport kinetics across the catalyst/substrate interface and also maintains the structural integrity of the
overall catalyst throughout the cyclic and long-term durability tests. Furthermore, the Ni@CoOOH provide
abundant active sites for the dissociation of water, while the PANi-CF facilitates the adsorption of H+ ions from
the intermediates and promotes its convention to hydrogen molecules, which accelerates the HER effectively.
Due to these intriguing features, the Ni@CoOOH@PANi-CF manifested remarkable HER efficiency with low
overpotential (35, 30, and 100 mV mV at 10 mA cm-2) in acidic, alkaline, and neutral electrolytes. Besides, the
Ni@CoOOH@PANi-CF demonstrated batter durability even in acidic electrolyte. As a key functionality, PANi
layers protected the carbon surface from corrosive reactions and suppressed the active catalyst dissolution,
resulting in high tolerance for both HER and OER at all pH conditions.
In Situ Investigation on Cl- Repellency Effect of Electrolyte Additive on NiOOH for Alkaline Sea Water Splitting
Authors: Ham Kahyun , Lim Ahyoun , Spanos Ioannis 
Published: February 2024

Sea water splitting can produce green hydrogen by feeding abundant sea water directly without high-qualified water purification process. However, excess cation such as Mg2+ and Ca2+ in sea water absorbs on the cathode surface, and it causes the loss of active site and activity toward hydrogen evolution reaction. At the anode side, oxygen evolution reaction (OER) should be competed with chlorine evolution reaction due to huge amount of Cl- ion, so operating in high pH electrolyte at low overpotential has been suggested to increase the selectivity toward OER. To further inhibit the adsorption of Cl-, some researchers have suggested using anion additive such as PO4
3- and SO4
2- in the alkaline electrolyte, but both adsorption stability of additive anion and the interaction between anion and metal oxide catalyst are still needed to be studied.
In this study, we investigated the Cl- repellency effect of additive anion in the electrolyte to NiOOH catalyst, known as state-of-the-art OER catalyst, for alkaline sea water splitting. To observe the change in adsorbate species by additive anion, we tracked the mass change of the catalyst during the reaction through in situ electrochemical quartz crystal microbalance (EQCM). Furthermore, Cl- can change (degrade) the NiOOH structure by formation of metal-chloride complex. Through in situ Raman spectroscopy, we observed the structural stability of NiOOH in presence of anion additive as well as the adsorption stability of additive anion depending on the applied potential.
UVC Emission Devices Based on Alternating Current Inorganic Electroluminescence Using Y2SiO5:Pr3+ Phosphors
Authors: Kang Taewook , Kim Sun Woog , Kim Jongsu 
Published: February 2024

Ultraviolet C (UVC: 200-280 nm) lighting is urgently required for a number of sterilization applications such as water and air disinfection, food processing, and medical sterilization. Compared to other UVC emission sources, AC-driven inorganic phosphor electroluminescent (EL) devices are appealing due to their wide viewing angle, fast response time, low power consumption, high contrast, simple manufacture, and cost effectiveness. Although the luminance of inorganic phosphor EL devices is typically low, it is sufficient for most low-cost lighting and large-area display applications. In addition, inorganic phosphor EL devices have the advantage of emitting light without generating much heat.
In this study, UVC emission was demonstrated through EL devices using a UVC phosphor. Pr3+-doped Y2SiO5 (Y2SiO5:Pr3+) is used for UVC light, Y2SiO5:Pr3+ phosphor shows a broad UVC emission at 280 nm from the f-d transition of Pr3+ ions as well as a sharp red emission at 610 nm from the f-f transition of Pr3+ ions. The phosphors were synthesized in three types to fabricate EL devices. The Y2SiO5:Pr3+ powder, film, and nano-powder formed the phosphor layers of EL devices by screen printing, spin coating, and electrophoretic deposition, respectively. In order to emit UVC light, patterned gold was used for transparent electrodes of the devices instead of conventional indium tin oxide (ITO), which absorbs the UV region. The EL devices were demonstrated in two types: powder EL and electrolyte EL. The fabricated EL devices showed a wide range of UVC emission from 260 nm to 330 nm. Finally, luminescent and electrical analysis of each device was performed to analyze the characteristics.
Towards High-Quality Broad-Range Luminescence Thermometry - the Case of Pr3+-Activated Garnets
Authors: Zych Eugeniusz , Kulesza Dagmara , Bolek Paulina , Jedoń Joanna , Trojan-Piegza Joanna , Zeler Justyna 
Published: February 2024

Accurate and sensitive remote temperature measurement over a wide range of temperatures, presumably 1000 degrees, is required in many existing and emerging applications. Novel and emerging technologies pose new requirements on the quality of temperature measuring, the resistance to disturbance by external electric and/or magnetic fields, spatial resolution, and the operating range of thermometers. Luminescence thermometry has the potential to become the technology of choice when classic methods become non-practical and/or do not offer the expected quality.
Designing a luminescence thermometer capable of measuring temperature reliably over, for example, 1000 degrees range is challenging, as managing luminescence processes in such a range is extremely difficult. Yet, wide-range luminescence thermometers are of interest in such fields as aviation, space, nuclear plant, and others. Fast, accurate, and credible measurements of quickly changing temperatures are critical in these areas.
In this presentation, we shall report on the thermometric competencies of a series of garnet phosphors, typically activated with Pr3+. We shall focus on the possibility of managing the physics related to energy flow between the excited levels of Pr3+ and thermal quenching of its three emissions resulting from the 5d®4f, 3PJ®3HJ and 1D2®3HJ transitions. Not only shall we demonstrate that the sensitivity of such sensors may be deliberately tuned to reach its maximum at temperatures where it is most needed, but we will also show that garnets nowadays may offer temperature measuring over a range of 800 degrees at least.

This research was supported by the Polish National Science Center (NCN) under the grant #UMO2018/29/B/ST5/00420.

Figure 1
Optimization of First-Principles Calculation Conditions for Ce3+ in Perovskite-Type Oxides
Authors: Hashimoto Hinaka , Ogasawara Kazuyoshi 
Published: February 2024

The 4f-5d transition of Ce3+ in crystals is used in a variety of optical materials, including scintillators and phosphors. It also has the advantages that the wavelength can be controlled by the coordination environment and that Ce3+ is relatively inexpensive among rare earth elements. For the theoretical design of novel Ce3+-doped phosphors, prediction of 4f-5d transition energy by first-principles molecular orbital calculations using model clusters is effective. In general, increase of the cluster size improves the accuracy of calculations and reduces the difference between the experimental and calculated values while very large clusters have the disadvantage of requiring a huge amount of calculation time. Hence, understanding the cluster size dependence is important to determine the efficient and effective cluster size for the first-principles calculations.
In this study we focused on Ce3+-doped in YAlO3, and performed first-principles calculations of the 4f-5d transition energies for model clusters with different sizes. At first, the local structures around the Y3+ site of YAlO3 were cut out from the crystal structure. Then the central Y3+ ions of these clusters were replaced by Ce3+ ions. Then the transition energy of Ce3+ in YAlO3 was calculated by the relativistic discrete-variational Xα (DV-Xα) molecular orbital calculations using the Slater's transition state method. The detailed comparison of the results showed that for clusters larger than a certain size, the error between the experimental and calculated values became negligibly small. For comparison, the lattice relaxation was also taken into account by modifying the model clusters using two different methods: the method based on the Shannon's crystal radii and the structural optimization using the CASTEP code, and the results were compared in detail.
Probing the Recombination Process at the Intermixed Interface of a Solution-Processed Organic Light Emitting Diode By Impedance Spectroscopy
Authors: Kim Ji Soo , Kim Youn Sang , Kwon Soon-Hyung 
Published: February 2024

Solution-processed organic light emitting diode (s-OLED) has garnered considerable research interest due to its cost-effectiveness, improved energy efficiency, and material-saving advantages over conventional vacuum deposition methods in OLED production. Recent studies have shown that the thermal annealing process of multilayered s-OLEDs induces intermixing at the interfaces of the layers and enhances the device performance [1,2]. However, the physical origin of the enhanced s-OLED performance by intermixing at the interfaces is poorly understood. To address this issue, we utilized electrical impedance spectroscopy (IS) to investigate the thermal-induced modifications of charge carrier dynamics in a bilayer s-OLED comprising an electron transporting layer (ETL) and an emission layer (EML). We separately assessed the conductance of the ETL and the charge carrier accumulation at the EML/ETL interface by the characteristic relaxation frequency and the plateau at a low frequency regime (20~100 Hz) extracted from the frequency-dependent capacitance spectra, respectively. The IS analysis revealed that improved charge transport in the ETL by thermal annealing process was mainly responsible for the performance enhancement, rather than intermixing at the EML/ETL interface. Notably, we found that annealing the s-OLEDs above the glass transition temperature (Tg) of the ETL, at which significant intermixing occurs, increased the magnitude of negative capacitance, indicating the increased rate of nonradiative trap-assisted recombination [3]. Accordingly, our IS analysis clarified that extended intermixing at the EML/ETL interface is rather detrimental to the performance of s-OLEDs. This study demonstrates that IS can serve as a powerful tool for accurately analyzing charge carrier dynamics in s-OLEDs by simultaneously probing charge transport, interfacial charge accumulation, and recombination processes, thereby providing valuable insights for optimizing s-OLED performance.
[1] ACS Appl. Mater. Interfaces
2015, 7 (37), 20779–20785. https://doi.org/10.1021/acsami.5b05818.
[2] Advanced Materials Interfaces
2019, 6 (4), 1801627. https://doi.org/10.1002/admi.201801627.
[3] Phys. Rev. Lett.
2018, 120 (11), 116602. https://doi.org/10.1103/PhysRevLett.120.116602.

Figure caption. The capacitance at 20 Hz and current efficiency at 100 nit are plotted against the ratio of annealing temperature (T) to glass transition temperature (Tg) of ETL.

Figure 1
Spectro-Electrochemiluminescence Analysis of the Simultaneous Emission of Two Luminophores
Authors: Ibáñez David , González-García María Begoña , Hernández-Santos David , Fanjul Pablo 
Published: February 2024

Electrochemiluminescence (ECL) is a powerful technique that combines the best features of electrochemistry and chemiluminescence in a single experiment. Its versatility, simplified optical set-up, low background signal and high sensitivity [1] allows the increase of new analytical applications. ECL signals are usually obtained from the excited states of a luminophore generated at the electrode surface during an electrochemical reaction due to the presence of a co-reactant. Particularly, resonance energy transfer (RET) mechanism is produced when at least two luminophores are present in solution, one luminophore acts as donor and the other one as acceptor [2]. In the absence of an external light source, donor luminophore emits light as consequence of its electrochemical excitation, part of this emission is absorbed by the acceptor to be excited and re-emits light.
Initially, ECL emission of two luminophores were separately analysed in this work: (1) luminol emission in presence of hydrogen peroxide as co-reactant shows one band from 350 to 600 nm (maximum at 420 nm) during its oxidation process at +0.20 V, while (2) ECL signal of Ru(bpy)3
2+ with tripropylamine as co-reactants displays one band at 620 nm at +0.95 V.
Furthermore, the simultaneous emission of luminol and Ru(bpy)3
2 (RET-ECL system) was analysed using a microspectrometer detector [3]. ECL spectra display three emission bands at 420, 510 and 620 nm. According to the previous experiments, bands at 420 and 510 nm should be associated with luminol due to its band emission is located from 350 to 600 nm, while band at 620 nm corresponds to Ru(bpy)3
2+. Nevertheless, Ru(bpy)3
2+ shows a characteristic absorption band at 450 nm, so minimum observed at this wavelength in the spectra is related to the Ru(bpy)3
2+ absorption. It demonstrates that bands at 420 and 510 nm are not really two bands, they form the characteristic band of luminol at 350-600 nm but is separated due to the characteristic absorption of Ru(bpy)3
2+ at 450 nm. Then, it is clear than Ru(bpy)3
2+ absorbs part of ECL emission of luminol before producing their own emission at more positive potentials. Spectro-electrochemiluminescence results demonstrates that the interaction between luminol and Ru(bpy)3
2+ is an important effect to be considered when ECL system is formed by these two luminophores.

References

[1] M.M. Richter, Chem. Rev. 104 (2004) 3003–3036.
[2] M.M.P.S. Neves, P. Bobes-Limenes, A. Pérez-Junquera, M.B. González-García, D. Hernández-Santos, P. Fanjul-Bolado, Anal. Bioanal. Chem. 408 (2016) 7121–7127.
[3] D. Ibáñez, M.B. González-García, D. Hernández-Santos, P. Fanjul-Bolado, Phys. Chem. Chem. Phys., 22 (2020) 18261-18264.