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Sang Bastian S, Rechberger F, Zellmer S, Niederberger M, Garnweitner G. Conducting ITO Nanoparticle-Based Aerogels—Nonaqueous One-Pot Synthesis vs. Particle Assembly Routes. Gels 2023; 9:gels9040272. [PMID: 37102884 PMCID: PMC10138307 DOI: 10.3390/gels9040272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/18/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Indium tin oxide (ITO) aerogels offer a combination of high surface area, porosity and conductive properties and could therefore be a promising material for electrodes in the fields of batteries, solar cells and fuel cells, as well as for optoelectronic applications. In this study, ITO aerogels were synthesized via two different approaches, followed by critical point drying (CPD) with liquid CO2. During the nonaqueous one-pot sol–gel synthesis in benzylamine (BnNH2), the ITO nanoparticles arranged to form a gel, which could be directly processed into an aerogel via solvent exchange, followed by CPD. Alternatively, for the analogous nonaqueous sol–gel synthesis in benzyl alcohol (BnOH), ITO nanoparticles were obtained and assembled into macroscopic aerogels with centimeter dimensions by controlled destabilization of a concentrated dispersion and CPD. As-synthesized ITO aerogels showed low electrical conductivities, but an improvement of two to three orders of magnitude was achieved by annealing, resulting in an electrical resistivity of 64.5–1.6 kΩ·cm. Annealing in a N2 atmosphere led to an even lower resistivity of 0.2–0.6 kΩ·cm. Concurrently, the BET surface area decreased from 106.2 to 55.6 m2/g with increasing annealing temperature. In essence, both synthesis strategies resulted in aerogels with attractive properties, showing great potential for many applications in energy storage and for optoelectronic devices.
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2
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Singh RK, Chen LH, Singh A, Jain N, Singh J, Lu CH. Progress of Backlight Devices: Emergence of Halide Perovskite Quantum Dots/Nanomaterials. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.863312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The technology behind the display is becoming ever more prevalent in our daily lives. It has many applications, including smartphones, tablets, desktop monitors, TVs, and augmented reality/virtual reality devices. The display technology has progressed drastically over the past decade, from the bulky cathode ray tube to the flat panel displays. In the flat panel displays, the liquid crystal display (LCD) and organic light-emitting diodes (OLEDs) are the two dominant technologies. Nevertheless, due to low stability and color tunability, OLEDs remain behind the LCDs. The LCD screen has a backlight, usually a white LED, which comprises a blue LED covered with a red and green enhanced layer (color-converting layers). Although InP/CdSe QDs attracted more attention due to their solution processability and better color gamut than the previous technologies, the complexity of their synthesis was still an obstacle to their commercialization. Later, the emergence of perovskite with highly intense and tunable PL emission, high color purity, and low-cost synthesis route attracted the attention of display researchers. Owing to the relatively higher performance of perovskite quantum dots (PQDs) than that of bulk (3D) perovskite in backlit display devices, these PQDs are being used for high color contrast and bright display devices. Furthermore, the color gamut for PQDs was observed as 140% of the NTSC standard, that is, close to that of the commercial OLED devices. In this review, we have discussed the progress of display technologies with a clear classification of the pros and cons of each technology. Also, the application of perovskite QD/nanomaterials in LCD backlit devices has been discussed, and the future direction of further improvement in their stability and performance has been listed.
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3
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Conception, Discovery, Invention, Serendipity and Consortia: Cyanobiphenyls and Beyond. CRYSTALS 2022. [DOI: 10.3390/cryst12060825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
In the 1960s, a world-wide change in electronic devices was about to occur with the invention of integrated circuits. The chip was upon us, which instantly created the need for a revolution in visual communication displays. From the watch to the computer monitor, to TVs, to the phone, nearly all everyday applications were affected. A strange connection in technology underpinned these changes; the linkage between silicon semiconductors and organic compounds that did not know if they were solids or liquids. Liquid crystals had been known since 1888 and had seen little usage until they were inserted between conducting glass slides and an applied electric field. Suddenly, the possibility of driving images with low voltage fields became obvious. Many major companies took up the challenge of commercialisation, but in the UK a curious combination of government research facilities, electronic companies and one small university came together in 1970 to form a consortium and within two years the basis for new technologies had been founded. Chemistry is part of this story, with new conceptions, discoveries and inventions, and the luck to be in the right place at the right time.
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4
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Optical characterization and γ-irradiation response of conductive transparent oxide of SnO2:Sb films. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Cho Y, Park H, Kim E, Jang M, Huh Y. Color Tuning of Light Emitted from the Cathodoluminescence of (Ca
1 −
x
Eu
x
)
Ga
2
S
4
Phosphors. B KOREAN CHEM SOC 2020. [DOI: 10.1002/bkcs.12105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Young‐Sik Cho
- Department of Chemistry Institute of Nanosensor and Biotechnology, Dankook University Chungcheongnam‐Do 31116 South Korea
| | - Hye‐Jin Park
- Department of Chemistry Institute of Nanosensor and Biotechnology, Dankook University Chungcheongnam‐Do 31116 South Korea
| | - Eung‐Dab Kim
- Department of Chemistry Institute of Nanosensor and Biotechnology, Dankook University Chungcheongnam‐Do 31116 South Korea
| | - Min‐Kyeong Jang
- Department of Chemistry Institute of Nanosensor and Biotechnology, Dankook University Chungcheongnam‐Do 31116 South Korea
| | - Young‐Duk Huh
- Department of Chemistry Institute of Nanosensor and Biotechnology, Dankook University Chungcheongnam‐Do 31116 South Korea
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Programming emergent symmetries with saddle-splay elasticity. Nat Commun 2019; 10:5104. [PMID: 31704934 PMCID: PMC6841980 DOI: 10.1038/s41467-019-13012-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 10/13/2019] [Indexed: 11/08/2022] Open
Abstract
The director field adopted by a confined liquid crystal is controlled by a balance between the externally imposed interactions and the liquid's internal orientational elasticity. While the latter is usually considered to resist all deformations, liquid crystals actually have an intrinsic propensity to adopt saddle-splay arrangements, characterised by the elastic constant [Formula: see text]. In most realisations, dominant surface anchoring treatments suppress such deformations, rendering [Formula: see text] immeasurable. Here we identify regimes where more subtle, patterned surfaces enable saddle-splay effects to be both observed and exploited. Utilising theory and continuum calculations, we determine experimental regimes where generic, achiral liquid crystals exhibit spontaneously broken surface symmetries. These provide a new route to measuring [Formula: see text]. We further demonstrate a multistable device in which weak, but directional, fields switch between saddle-splay-motivated, spontaneously-polar surface states. Generalising beyond simple confinement, our highly scalable approach offers exciting opportunities for low-field, fast-switching optoelectronic devices which go beyond current technologies.
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7
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Boudoire F, Partel S, Toth R, Heier J. Combining parallel pattern generation of electrohydrodynamic lithography with serial addressing. RSC Adv 2018; 8:30932-30936. [PMID: 35548741 PMCID: PMC9085484 DOI: 10.1039/c8ra06160b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 08/27/2018] [Indexed: 11/28/2022] Open
Abstract
Electrohydrodynamic lithography (EHDL) is a parallel patterning process which typically makes use of topographically structured electrodes to guide pattern formation along areas of higher electrical field strength. The main driving force for pattern formation is an electrostatic pressure acting on a thin film polymer surface caused by a voltage applied between a top and bottom electrode. We here demonstrate that the principle can be applied using an addressable electrode composed of interdigitated fingers. Depending on the applied voltages, line patterns with different periodicities were fabricated. Our proof-of-concept experiments pave the way for a parallel pattern replication process where a serially addressed master is used. We complement the experiments by modelling the potentials across the electrodes and electrostatic forces acting on the polymer surface using different addressing schemes. Numerical simulations of the experimental setup pointed to some critical issues we experienced during the design of the experiments. Via different electrode addressing schemes in electrohydrodynamic lithography, different patterns were generated.![]()
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Affiliation(s)
- F. Boudoire
- Empa
- Swiss Federal Laboratories for Materials Science and Technology
- Laboratory for Functional Polymers
- Switzerland
- Empa
| | - S. Partel
- Vorarlberg University of Applied Sciences
- 6850 Dornbirn
- Austria
| | - R. Toth
- Empa
- Swiss Federal Laboratories for Materials Science and Technology
- Laboratory for High Performance Ceramics
- Switzerland
| | - J. Heier
- Empa
- Swiss Federal Laboratories for Materials Science and Technology
- Laboratory for Functional Polymers
- Switzerland
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8
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Tigaa RA, Aerken X, Fuchs A, de Bettencourt‐Dias A. Sensitization of Ln
III
(Ln = Eu, Tb, Tm) Ion Luminescence by Functionalized Polycarbonate‐Based Materials and White Light Generation. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rodney A. Tigaa
- Department of Chemistry University of Nevada 89557‐216 Reno NV USA
| | - Xuekelaiti Aerken
- Department of Chemical and Materials Engineering University of Nevada 89557‐388 Reno NV USA
| | - Alan Fuchs
- Department of Chemical and Materials Engineering University of Nevada 89557‐388 Reno NV USA
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9
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Felix-Serrano I, Trejo-Carbajal N, Rodríguez-González RJ, Larios-López L, Moggio I, Arias E, Torres-Lubián R, Navarro-Rodríguez D. Synthesis and liquid-crystalline properties of methacrylate monomers carrying a p -terphenyl laterally substituted with one or two cyano groups. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.06.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Fialho AR, Bernardino NR, Silvestre NM, Telo da Gama MM. Effect of curvature on cholesteric liquid crystals in toroidal geometries. Phys Rev E 2017; 95:012702. [PMID: 28208389 DOI: 10.1103/physreve.95.012702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Indexed: 11/07/2022]
Abstract
The confinement of liquid crystals inside curved geometries leads to exotic structures, with applications ranging from biosensors to optical switches and privacy windows. Here we study how curvature affects the alignment of a cholesteric liquid crystal. We model the system on the mesoscale using the Landau-de Gennes model. Our study was performed in three stages, analyzing different curved geometries from cylindrical walls and pores, to toroidal domains, in order to isolate the curvature effects. Our results show that the stresses introduced by the curvature influence the orientation of the liquid crystal molecules, and cause distortions in the natural periodicity of the cholesteric that depend on the radius of curvature, on the pitch, and on the dimensions of the system. In particular, the cholesteric layers of toroidal droplets exhibit a symmetry breaking not seen in cylindrical pores and that is driven by the additional curvature.
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Affiliation(s)
- Ana R Fialho
- Departamento de Física da Faculdade de Ciências, Centro de Física Teórica e Computacional, Universidade de Lisboa, P-1649-003 Lisboa, Portugal
| | - Nelson R Bernardino
- Departamento de Física da Faculdade de Ciências, Centro de Física Teórica e Computacional, Universidade de Lisboa, P-1649-003 Lisboa, Portugal
| | - Nuno M Silvestre
- Departamento de Física da Faculdade de Ciências, Centro de Física Teórica e Computacional, Universidade de Lisboa, P-1649-003 Lisboa, Portugal
| | - Margarida M Telo da Gama
- Departamento de Física da Faculdade de Ciências, Centro de Física Teórica e Computacional, Universidade de Lisboa, P-1649-003 Lisboa, Portugal
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11
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Kim KH, Kim SJ, Lee TH, Lee BR, Kim TG. Performance of GaN-on-Si-based vertical light-emitting diodes using silicon nitride electrodes with conducting filaments: correlation between filament density and device reliability. OPTICS EXPRESS 2016; 24:17711-17719. [PMID: 27505739 DOI: 10.1364/oe.24.017711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Transparent conductive electrodes with good conductivity and optical transmittance are an essential element for highly efficient light-emitting diodes. However, conventional indium tin oxide and its alternative transparent conductive electrodes have some trouble with a trade-off between electrical conductivity and optical transmittance, thus limiting their practical applications. Here, we present silicon nitride transparent conductive electrodes with conducting filaments embedded using the electrical breakdown process and investigate the dependence of the conducting filament density formed in the transparent conductive electrode on the device performance of gallium nitride-based vertical light-emitting diodes. Three gallium nitride-on-silicon-based vertical light-emitting diodes using silicon nitride transparent conductive electrodes with high, medium, and low conducting filament densities were prepared with a reference vertical light-emitting diode using metal electrodes. This was carried to determine the optimal density of the conducting filaments in the proposed silicon nitride transparent conductive electrodes. In comparison, the vertical light-emitting diodes with a medium conducting filament density exhibited the lowest optical loss, direct ohmic behavior, and the best current injection and distribution over the entire n-type gallium nitride surface, leading to highly reliable light-emitting diode performance.
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12
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Cho YS, Huh YD. Cathodoluminescence Properties of Red-Emitting Sr1−xCaxS:Eu Phosphors. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Young-Sik Cho
- Department of Chemistry; Center for Photofunctional Energy Materials, Dankook University; Gyeonggi-Do 448-701 Korea
| | - Young-Duk Huh
- Department of Chemistry; Center for Photofunctional Energy Materials, Dankook University; Gyeonggi-Do 448-701 Korea
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13
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Jones JC. Rising in the east: ‘The Liquid Crystal Display Story’, edited by N. Koide. LIQUID CRYSTALS TODAY 2015. [DOI: 10.1080/1358314x.2015.1050842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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3-(4-Bromophenyl)-5-(4-hydroxyphenyl)isoxazole: a versatile, new molecular building block for side-chain liquid crystal oligomers and polymers. Polym Bull (Berl) 2015. [DOI: 10.1007/s00289-015-1529-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Cho YS, Huh YD. Fine-Tuning the Emission Color of a Transparent Suspension of SrMoO4:Eu3+,Tb3+Nanophosphors. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Young-Sik Cho
- Department of Chemistry, Center for Photofunctional Energy Materials; Dankook University; Gyeonggi-Do 448-701 Korea
| | - Young-Duk Huh
- Department of Chemistry, Center for Photofunctional Energy Materials; Dankook University; Gyeonggi-Do 448-701 Korea
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16
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1,2,4-Oxadiazole-Based Bent-Core Liquid Crystals with Cybotactic Nematic Phases. Chemphyschem 2014; 15:1323-35. [DOI: 10.1002/cphc.201301070] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Indexed: 11/07/2022]
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17
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Innocenzi P, Malfatti L. Mesoporous thin films: properties and applications. Chem Soc Rev 2013; 42:4198-216. [PMID: 23396534 DOI: 10.1039/c3cs35377j] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Plinio Innocenzi
- Laboratorio di Scienza dei Materiali e Nanotecnologie (LMNT), D.A.D.U., CR-INSTM, Università di Sassari, Palazzo Pou Salid, Piazza Duomo 6, 07041 Alghero (SS), Italy.
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18
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Hsu PC, Wu H, Carney TJ, McDowell MT, Yang Y, Garnett EC, Li M, Hu L, Cui Y. Passivation coating on electrospun copper nanofibers for stable transparent electrodes. ACS NANO 2012; 6:5150-5156. [PMID: 22548313 DOI: 10.1021/nn300844g] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Copper nanofiber networks, which possess the advantages of low cost, moderate flexibility, small sheet resistance, and high transmittance, are one of the most promising candidates to replace indium tin oxide films as the premier transparent electrode. However, the chemical activity of copper nanofibers causes a substantial increase in the sheet resistance after thermal oxidation or chemical corrosion of the nanofibers. In this work, we utilize atomic layer deposition to coat a passivation layer of aluminum-doped zinc oxide (AZO) and aluminum oxide onto electrospun copper nanofibers and remarkably enhance their durability. Our AZO-copper nanofibers show resistance increase of remarkably only 10% after thermal oxidation at 160 °C in dry air and 80 °C in humid air with 80% relative humidity, whereas bare copper nanofibers quickly become insulating. In addition, the coating and baking of the acidic PEDOT:PSS layer on our fibers increases the sheet resistance of bare copper nanofibers by 6 orders of magnitude, while the AZO-Cu nanofibers show an 18% increase.
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Affiliation(s)
- Po-Chun Hsu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
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19
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Solin N, Inganäs O. Protein Nanofibrils Balance Colours in Organic White-Light-Emitting Diodes. Isr J Chem 2012. [DOI: 10.1002/ijch.201100113] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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20
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21
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Ludi B, Olliges-Stadler I, Rossell MD, Niederberger M. Extension of the benzyl alcohol route to metal sulfides: “nonhydrolytic” thio sol–gel synthesis of ZnS and SnS2. Chem Commun (Camb) 2011; 47:5280-2. [DOI: 10.1039/c1cc10856e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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