bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Blue-Light Emitting Ag-Ga-S Quantum Dots for LED Application
Authors: Tozawa Makoto , Ofuji Shuto , Akiyoshi Kazutaka , Kameyama Tatsuya , Motomura Genichi , Fujisaki Yoshihide , Uematsu Taro , Kuwabata Susumu , Torimoto Tsukasa 
Published: December 2024

Quantum dots (QDs), semiconductor nanocrystals smaller than 10 nm, can have their energy gap (Eg) adjusted by size due to the quantum size effect. So far, binary chalcogenide QDs, such as CdSe and PbS, have been widely investigated for their applications to liquid crystal displays and light-emitting diodes (LEDs), because they exhibit sharp photoluminescence (PL) peak with high quantum yields (QYs) and the PL peak wavelength can be controllable with the QD size. However, the use of toxic heavy metals such as Cd and Pb in these QDs poses significant environmental and health risks. To address this, we have developed multinary QDs using less toxic materials, such as Ag-In-Ga-S (AIGS), which exhibit sharp band-edge emission tunable from 500 to 600 nm by adjusting the In/Ga ratio [1]. Surface coating with gallium sulfide (GaSx) shell enhanced the peak intensity of band-edge emission due to the removal of the surface defect sites. We also successfully prepared green-light-emitting QD-LEDs with the use of AIGS QDs [2]. In this study, we report the synthesis of blue-light emissive QDs with AgGaS2 semiconductor, the bulk Eg of which is 2.7 eV. The obtained QDs exhibited a band-edge PL peak with a narrow peak width. These AgGaS2 QDs have been successfully utilized in the fabrication of blue-light QD-LEDs.
AgGaS2 QDs were synthesized by heating corresponding metal precursors and sulfur compounds in a mixture of oleylamine and 1-dodecanethiol. The resulting QDs were surface-coated with GaSx shell. TEM analysis revealed that spherical or polygonal nanoparticles with an average size of ca. 5 nm were formed. It was found from XRD measurements that the AgGaS2 QDs had a tetragonal crystal structure. Absorption spectra of AgGaS2 QDs were blue-shifted from ca. 460 nm to 450 nm with a decrease in the Ag/Ga ratio in the precursors. The obtained QDs exhibited a sharp band-edge PL peak at ca. 450 nm as well as a broader defect-site emission peak at longer wavelengths. The surface coating with GaSx shell to form core-shell-structured AgGaS2@GaSx QDs enhanced the band-edge PL peak, the peak width of which was 22nm. This was probably because the deposition of the GaSx shell eliminated surface defect sites acting as a non-radiative recombination site on AgGaS2 cores. QD-LEDs were fabricated with thus-obtained blue-emitting QDs as an electroluminescence layer. The resulting QD-LEDs exhibited a sharp electroluminescence peak at ca. 450 nm with an external quantum efficiency of 0.66%, demonstrating their potential in blue-light QD-LED applications.

References

[1] T. Kameyama, et al., ACS Appl. Mater. Interfaces
2018, 10, 42844-42855.
[2] G. Motomura, et al., ACS Appl. Mater. Interfaces
2023, 15, 8336–8344.
(Invited) Synergistic Interactions of Co-Dopants for Phosphor Functionalization
Authors: Zych Eugeniusz , Kulesza Dagmara , Zeler Justyna , Bukowska Paulina , Łukaszczuk Pola K. , Sójka Małgorzata , Carlos Luis D. , Brites Carlos D.S. 
Published: December 2024

The functionalization of phosphors through co-dopant interactions represents an effective and encouraging avenue for enhancing their luminescent characteristics. Co-doping introduces additional dopant species into the host lattice, leading to intricate interactions that influence the material's luminescence behavior. The synergistic effects arising from co-dopant interactions result in tailored luminescent characteristics, including emission wavelength tuning and improved performance in diverse applications such as lighting, displays, biomedical imaging, temperature measurement, and thermal imaging. By elucidating the intricacies of co-dopant interactions, this research contributes to the rational design and optimization of functionalized phosphors for advanced technological applications. By carefully selecting and controlling the dopants, researchers can tailor the luminescent characteristics of phosphors to meet specific requirements, thereby unlocking their full potential. This presentation focuses primarily on possible advantages of using this approach in luminescence thermometry and thermal imaging.
Co-activating phosphors facilitates the development of multifunctional materials with diverse, not only luminescent, properties. By carefully selecting dopant combinations, controlling their concentrations, and managing the technological parameters, precisely designed phosphors exhibiting multi-modal functionalities can be fabricated.
In the presentation, we will show examples of the effective use of co-doping phosphors with selected lanthanide ions or a lanthanide and a d-element. An exemplary case is presented in Figure 1, where temperature-dependent luminescence spectra of a triply-activated strontium aluminate phosphor are presented together with the relative thermal sensitivities derived from decay times of the different emissions.
The Polish National Science Centre (NCN) financed the research under OPUS grant #UMO2023/49/B/ST5/04265.

Figure 1
Temperature Dependence of Mn4+ Emission Intensity and Lifetime in TriGain® Phosphor (K2SiF6:Mn4+)
Authors: Cohen William Erwin , Du Fangming , Beers William Winder , Brik Mikhail G. , Srivastava Alok M. 
Published: December 2024

The modern-day pc-LEDs for general illumination is based on a blue-emitting InGaN chip coated with a blend of two phosphors, a green-yellow Cerium-doped garnet phosphor and a red phosphor which is required to induce a “warm-white” color temperature (2700–3500 K). Currently, one of the phosphors that satisfies the key performance requirements of a red emitter for white light pc-LED is the K2SiF6:Mn4+ (PFS/KFS) phosphor [1-3]. The phosphor is manufactured by Current Chemicals and sold under the trade name, TriGain®.
In this talk the temperature dependence of the Mn4+ luminescence and lifetime in TriGain® is discussed (Figure 1). The results are discussed in terms of dynamically induced increase in emission intensity and decay rate coupled with an Arrhenius-type thermal quenching. The parameters of our fitting to physical models are compared with those reported on laboratory synthesized K2SiF6:Mn4+ phosphor. This comparative study sheds light on factors responsible for non-radiative relaxation processes, which is fundamental to the understanding of phosphor quantum efficiency and performance. Due to low thermal conductivity of K2SiF6, it was necessary to develop protocols to ensure that the surface temperature of the phosphor was close to that of the cold finger in the closed cycle He cryostat. These will be discussed.
References:

M.G. Brik and A.M. Srivastava, J. Lumin., 133, 69 (2013).

W.E. Cohen, F. Du, W. W. Beers and A. M. Srivastava, ECS J. Solid State Sci. Technol., 12, 076004 (2023)

W.W. Beers, W. E. Cohen, A. M. Srivastava, ECS J. Solid State Sci. Technol.,12 (2023) 116002.

Figure 1
(Invited) Applications of Mn4+ and Cr3+ Ions for Lighting and Optical Thermometry
Authors: Brik Mikhail G. , Dramicanin Miroslav , Srivastava Alok M. , Beers William Winder , Cohen William E. , Piasecki Michal , Ma Chong-Geng , Kurboniyon Mekhrdod , Yamamoto Tomoyuki 
Published: December 2024

Transition metal ions with the 3d3 electron configuration (Cr3+ and Mn4+, in particular) are widely used for the lighting (red and deep red emission) and non-contact optical thermometry. This is due to their specific energy level scheme and favorable relative position of the spin-quartet state 4T2 and spin-doublet state 2E. Complicated interplay of electronic properties of impurity ions and host materials (covalent bonding between dopants and ligands) is the main reason for wide tunability of emission wavelength of such phosphors. The main goal of this presentation is to review the fundamental spectroscopic properties of Mn4+ and Cr3+ ions to illustrate the fundamental role of the “structure-optical property” relationships and to illustrate how such studies can have applied importance as useful guides facilitating search for new efficient phosphors [1-9].
References:
[1] M. G. Brik, A. M. Srivastava J. Lumin. 133 (2013) 69.
[2] M.G. Brik, S. J. Camardello, A. M. Srivastava, ECS J. Solid State Sc. and Technol. 41 (2015) R39.
[3] M. G. Brik, W. W Beers, W. Cohen, S. A. Payne, N. J. Cherepy, M. Piasecki, A. M. Srivastava, Opt. Mat. 91 (2019) 338.
[4] W. W Beers, D. J. Smith, W. E. Cohen, A. M. Srivastava, Opt. Mat. 84 (2018) 614.
[5] A. M. Srivastava, H. A. Comanzo, D. Smith, J. W. Choi, M. G. Brik, W. W. Beers, S. A. Payne, J. Lumin. 06 (2019) 398.
[6] M. Dramićanin, B. Milićević, V. Đorđević, Z. Ristić, J. Zhou, D. Milivojević, J. Papan, M. G. Brik, C-G Ma, A. M. Srivastava, ChemistrySelect. 4 (2019) 7067.
[7] J. Ueda, M. Back, M. G. Brik, Y. Zhuang, M. Grinberg, S. Tanabe, Opt. Mat., 85 (2018) 510.
[8] L. Marciniak, K. Kniec, K. Elżbieciak-Piecka, K. Trejgis, J. Stefanska, M. Dramićanin, Coord. Chem. Rev., 469 (2022) 214671.
[9] Y. Qin, F. Zhong, Y. Bian, S. Hariyani, Y. Cao, J. Brgoch, T. Seto, M. G. Brik, A. M. Srivastava, X. Wang, Y. Wang, Inorg. Chem., 61 (2022) 8126.
Optimizing Multifunctional Phosphors: Thermoluminescence and Luminescence Thermometry Processes
Authors: Zeler Justyna , Grzesiak Dominika , Małoń Aleksandra , Owczarek Aleksandra , Carlos Luis D. , Zych Eugeniusz 
Published: December 2024

Multifunctional phosphors are extremely important in various applications, ranging from lighting to biomedical purposes. By employing thermoluminescence and luminescence thermometry-related techniques, the intricate processes governing the luminescent behavior of these phosphors can be better understood and controlled.
Our study focuses on investigating the thermometric and thermoluminescent properties of Cr3+-activated aluminate family materials, with a specific focus on the effects of co-doping with various lanthanide ions. Through systematic analysis, we aim to understand the influence of lanthanide co-doping on the temperature response and thermoluminescent properties of the phosphors, which can offer valuable insights into using these materials in biological applications.
The ultimate goal of our project is to incorporate these functionalized materials into cancer cells and understand their optical characteristics as theranostic materials, as shown in Figure 1. We will comprehensively examine physical processes related to thermo- and persistent luminescence and other thermally stimulated emissions in designed luminescent materials. Our goal is to gain valuable insights into optimizing their functionalities for future bio- and medical applications.

The research finances by the Polish National Science Centre under OPUS grant #UMO2023/49/B/ST5/04265.

Figure 1
Thermally Invariant, Highly Sensitive, Ratiometric Luminescent Manometry Based on Cr3+ Emission
Authors: Szymczak Maja , Runowski Marcin , Wozny Przemyslaw , Marciniak Lukasz 
Published: December 2024

Pressure measurement leveraging the spectral response of a luminophore, known as luminescence manometry, presents numerous significant advantages over alternative detection methods, including rapid and dynamic response, electrical passivity, minimal invasiveness, and the capability for remote readings. Despite its recognition since the 1970s[1], the technique exhibits certain limitations. The current mainstream approach, employing a spectral shift of the 2E→4A2 band in Al2O3:Cr3+, offers high precision readouts but lacks sensitivity independence. Moreover, two-dimensional mapping of pressure variations using this methodology proves to be both time-consuming and economically burdensome.
To surmount these obstacles and facilitate thermally independent imaging of pressure changes, a novel technique is proposed that utilizes the ratio of emission intensities from the broad 4T2→4A2 band of Cr3+ ions, integrated across two distinct spectral regions[2-4]. The variation in crystal field strength impacting the Cr3+ ions, due to the compression of the material, prompts a shift in the spectral band, thereby altering the Luminescence Intensity Ratio (LIR) value. Conversely, temperature fluctuations have negligible (if any) impact on the spectral positioning of this band. Consequently, the application of this innovative method enables the realization of thermally independent imaging of pressure alterations. The practical viability of this strategy will be substantiated through various experimental demonstrations.
References
[1] R. A. Forman, G. J. Piermarini, J. Dean Barnett, S. Block, Science, 176, (1972) 284.
[2] M. Szymczak, P. Woźny, M. Runowski, M. Pieprz, V. Lavín, L. Marciniak, Chem Eng J, 453 (2022) 139632.
[3] M. Szymczak, M.Runowski, M.G. Brik, L. Marciniak, Chem Eng. J. 466 (2023) 143130.
[4] M. Szymczak, J. Jaskielewicz, M. Runowski, J. Xue, S, Mahlik, L. Marciniak, , Adv Funct Mater (2024) DOI: 10.1002/adfm.202314068.
Acknowledgements
This work was supported by the National Science Center (NCN) Poland under project no. DEC-UMO- 2020/37/B/ST5/00164.
Fabrication of (K,Rb)2CuCl3 and (K,Rb)2CuBr3 Single Crystal Scintillators with Efficient Luminescence
Authors: Yamabayashi Keishi , Okazaki Kai , Nakauchi Daisuke , Kawaguchi Noriaki , Kato Takumi , Yanagida Takayuki 
Published: December 2024

Scintillators are phosphor materials that emit many low-energy photons upon exposure of high-energy ionizing radiation such as X- and γ-rays. They have been utilized in combination with photodetectors for radiation measurements, including medical imaging [1], underground resources exploration [2], luggage inspection [3], and structural analysis of materials [4]. The required characteristics of scintillators are different depending on the applications. For example, high light yield (LY) for high energy resolution and high signal-noise ratio, short decay time for high time resolution, large effective atomic number for high interaction probability with ionizing radiation, and low hygroscopicity for long-term usability are important. Halide crystals such as Tl-doped CsI and NaI have been utilized as practical scintillators because of their high LY owing to the medium bandgap energy (5.8–6.3 eV) [4, 5]. However, most halide crystals have issues related to chemical instability due to hygroscopicity. Thus, novel non-hygroscopic scintillators with high LY have been desired.
Nowadays, Cu-based halide scintillators have received attention owing to good properties such as high photoluminescence quantum yield (PLQY), scintillation LY, and no hygroscopicity. We have focused on the alkali copper halide group such as A
2CuX
3 (A = K, Rb X = Cl, Br). They showed high PLQY (~100%) attributed to the recombination of self-trapped excitons under UV and X-ray irradiations [6, 7]. However, their scintillation LYs under γ-rays have not been clarified. According to Hume-Rothery rules [8], a continuous solid solution containing two or more components can be easily formed when two substances with similar ionic radius and crystal structure are partially mixed in the matrix. In continuous solid solutions, emission properties of phosphors were improved by optimizing energy levels in the bandgap and lattice defects involved in the luminescence [9]. On the basis of the rules, the continuous solid solutions of (K,Rb)2CuCl3 and (K,Rb)2CuBr3 can be grown. Thus, we fabricated (K,Rb)2CuCl3 and (K,Rb)2CuBr3 to enhance the scintillation properties. In this presentation, the scintillation properties such as the X-ray-induced scintillation spectra, the scintillation decay curves, afterglow curves, and pulse-height spectra of 1
37Cs γ-rays (662 keV) measurements will be presented.
[1] C.W. Eijk., Phys. Med. Biol., 47 (2002) R85. [2] A. Nikitin et.al., IEEE Nucl. Sci. Symp. Med. Imag. Conf. (2010) 1214. [3] V.D. Ryzhikov et.al., IEEE Symposium Conference Record Nuclear Science (2004) 4291. [4] V.V. Nagarkar et.al., IEEE Trans. Nucl. Sci.
45 (1998) 492. [5] M. Moszynski et.al., Nucl. Instrum. Methods Phys. Res. A (2004) 4291. [6] T.D Creason et.al., Chem. Mater.
32 (2020).
Electrocatalytic Hydrogenation of Pyridines in an Anion-Exchange Membrane (AEM) Reactor and Its Mechanistic Analysis by in Situ XAFS Measurement
Authors: Harada Juri , Shimizu Yugo , Yonezawa Akizumi , Kurihara Ryo , Iguchi Shoji , Kamiya Kazuhide , Shida Naoki , Atobe Mahito 
Published: December 2024

Cyclic amines are useful compounds used as building blocks of pharmaceuticals. According to the US Food and Drug Administration (FDA), approximately 20 % of small molecular pharmaceuticals contain cyclic amines, which can be obtained by hydrogenation of nitrogen-containing aromatic compounds. Notably, piperidines are prominent among inhibitor, antihistamine, and anesthetic. [1]

A number of reactions using homogeneous [2] and heterogeneous [3] catalysts have been reported for the production of cyclic amines via hydrogenation of nitrogen-containing aromatic compounds. However, these require high temperature and high-pressure conditions and H2 gas as a reductant, leading to a large amount of energy consumption and CO2 emission. In addition, acid is also used in these hydrogenation reactions to activate the nitrogen-containing aromatic compounds in some cases. However, this procedure requires neutralization and purification processes in the reaction workup, and causes corrosion of the reactor. In contrast, electrochemical hydrogenation of nitrogen-containing aromatic compounds is a promising method because electrochemical reactions can be carried out under mild conditions. For example, the reduction of pyridine to piperidine requires six electrons and six protons. However, it is difficult to obtain the desired piperidine by direct electron transfer through conventional cathodic reduction because of the formation of radical anions, resulting in dimerization and partial hydrogenation reactions. [4]

In this work, we developed an electrocatalytic hydrogenation system using an anion exchange membrane (AEM) reactor. Using an AEM reactor equipped with carbon-supported Rh as the cathode catalyst, the hydrogenation of pyridine to piperidine was achieved at ambient temperature and pressure without any additives in the catholyte.
To gain insights into the reduction behavior of carbon-supported Rh during electrolysis, we also performed Rh K-edge in situ X-ray absorption fine structure (XAFS) measurements using a tailor-made AEM reactor equipped with polyimide windows for the X-rays. As a result, Rh (0) was found to be an active catalyst for the electrocatalytic hydrogenation of pyridine.
The authors gratefully acknowledged support by JST CREST Grant No. JP65R1204400, Japan.
[1] E. Vitaku, D. T. Smith, and J. T. Njardarson, J. Med. Chem.
2014, 57, 10257–10274.
[2] R. Adam, J. R. Cabrero-Antonino, A. Spannenberg, K. Junge, R. Jackstell, and M. Beller, Angew. Chem.
2017, 129, 3264–3268.
[3] K. Murugesan, V. G. Chandrashekhar, C. Kreyenschulte, M. Beller, R. V. Jagadeesh, Angew. Chem. Int. Ed.
2020
, 59, 17408–17412.
[4] J. G. Keay Comprehensive Organic Synthesis
1991, 8, 579-602.

Figure 1
Phenol-Mediated Proton Shuttling Enables Electrochemical Hydrogenation of Phenol in Alkaline Electrolytes on Rhodium
Authors: Markunas Brianna , Snyder Joshua David 
Published: December 2024

Thermal chemical hydrogenation (TCH) is a key reaction for upgrading petroleum and biomass feedstocks to value- added fuels and chemicals. TCH requires high operating temperatures and pressures which results in high energy consumption and CO2 emissions. Electrochemical hydrogenation (ECH) is a mild alternative where applied potential drives the hydrogenation of hydrocarbons with protons from the aqueous electrolyte near ambient conditions. Phenol is a simple representative compound for renewable lignocellulosic feedstocks that has been the focus of recent ECH studies. The added complexity from the electrolyte and applied potential in aqueous ECH systems requires a fundamental understanding of these reaction parameters on ECH activity in-order to overcome current limitations, including faradaic efficiency losses to the competitive hydrogen evolution reaction (HER). Furthermore, the wide range of reaction conditions employed in the phenol ECH literature makes comparison of the ECH performance difficult. Phenol ECH on PGMs is commonly performed in electrolytes in a pH range of 1-5, assuming that the ECH of phenol follows a Langmuir Hinshelwood (LH) mechanism [1, 2]. One study reported a 95% faradaic efficiency (FE) for phenol ECH on rhodium at pH 10 [3], but no further investigation into the source of this promising activity at alkaline pH has been conducted.
In this work we study the role of electrolyte pH on phenol ECH on platinum and rhodium. We show that there are differing pH trends for ECH activity between platinum and rhodium, with the highest ECH rates on platinum at pH 1 and the highest rates on rhodium at pH 9, near the pka of phenol. We show using cyclic voltammetry and in-situ electrochemical FTIR that this pH dependent behavior results from the interplay between hydrogen adsorption kinetics, differences in phenol/hydrogen coverage on each metal, and competition with HER. We show that the electrolyte pH dictates the balance between a hydrogen atom transfer (LH) mechanism and a phenol-mediated proton coupled electron transfer mechanism. With this insight, we show that the unique properties of rhodium and the acid-base chemistry of phenol and the electrolyte buffer can be leveraged for higher ECH rates and FE.
[1] Singh, N., et al., Aqueous Phase Catalytic and Electrocatalytic Hydrogenation of Phenol and Benzaldehyde over Platinum Group Metals. Journal of Catalysis 2020, 382, 372–384. https://doi.org/10.1016/j.jcat.2019.12.034.
[2] Song, Y., et al., Integrated Catalytic and Electrocatalytic Conversion of Substituted Phenols and Diaryl Ethers. Journal of Catalysis 2016, 344, 263–272. https://doi.org/10.1016/j.jcat.2016.09.030.
[3] Song, Y., et al., Aqueous Phase Electrocatalysis and Thermal Catalysis for the Hydrogenation of Phenol at Mild Conditions. Applied Catalysis B: Environmental 2016, 182, 236–246. https://doi.org/10.1016/j.apcatb.2015.09.027.
An Electrochemiluminescence Device Powered By Streaming Potential for the Detection of Amines
Authors: Inagi Shinsuke , Suzuki Rintaro , Iwai Suguru , Villani Elena , Sato Kosuke , Hasegawa George , Ishizuka Norio , Matsukawa Kimihiro 
Published: December 2024

Herein, we report the design, development and optimization of an electrochemiluminescence (ECL) device powered by streaming potential for the detection of amines in flowing solution that can be activated without the need of an electric power supply (Figure 1). The device is based on the concept of streaming potential-driven bipolar electrochemistry [1,2], in which a flow of electrolytic solution passing through a microchannel with charged walls under a pressure gradient causes a streaming potential (E
str) as the driving force of bipolar electrodes (BPE).
In this study, we explored several experimental parameters to find the optimal operating conditions to drive the coreactant-type ECL reaction of a benzothiadiazole-triphenylamine (BTD-TPA) derivative in our streaming potential-driven device. The ECL emission was successfully detected by a photomultipulier tube (PMT), a digital camera and a spectrometer under the optimized electrolyte conditions including tripropylamine (TPrA) as a coreactant. Finally, we tested the ECL detection of several amines used as coreactants with the device.
References:

I. Dumitrescu, R. K. Anand, S. E. Fosdick, R. M. Crooks, J. Am. Chem. Soc., 2011, 133, 4687.

S. Iwai, T. Suzuki, H. Sakagami, K. Miyamoto, Z. Chen, M. Konishi, E. Villani, N. Shida, I. Tomita, S. Inagi, Commun. Chem., 2022, 5, 66.

Figure 1