Synthesis and characterization of novel polyphenol species derived from bis(4-aminophenyl)ether: Substituent effects on thermal behavior, electrical conductivity, solubility, and optical band gap

2008 ◽  
Vol 110 (1) ◽  
pp. 539-549 ◽  
Author(s):  
İsmet Kaya ◽  
Mehmet Yıldırım
2019 ◽  
Vol 6 (9) ◽  
pp. 095602 ◽  
Author(s):  
Ömer Güler ◽  
Seval Hale Güler ◽  
Öyküm Başgöz ◽  
M Gökhan Albayrak ◽  
I S Yahia

Nano Hybrids ◽  
2014 ◽  
Vol 6 ◽  
pp. 37-46 ◽  
Author(s):  
Tansir Ahamad ◽  
Saad M. Alshehri

Two different batches of Gallium (III) sulphide nanocrystals, (α-Ga2S3)1 and (α-Ga2S3)2 were synthesized at room temperature by the reaction of Gallium (III) chloride with sodium thiosulphate in water for 10 and 20 min respectively. The resultant nanoparticles were characterized by different spectroscopic techniques. TEM micrographs showed well-defined, close to hexagonal particles, and the lattice fringes in the HRTEM images confirmed their nanocrystalline nature. The sizes of (α-Ga2S3)1 and (α-Ga2S3)2 were 12 and 35 nm respectively with similar morphologies. Optical band gap energies (3.43 eV/3.41 eV) and photoluminescence peaks 635/641 nm (red shift) and 414/420 nm (blue shift) of the synthesized α-Ga2S3 nanocrystals suggest that they may be promising photocatalysts. Raman spectra for the α-Ga2S3, shows very sharp bands at 119, 135 and 148 cm-1 due to Ga-S2 scissoring.


e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Toheed Akhter ◽  
Humaira Masood Siddiqi ◽  
Zareen Akhter ◽  
M. Saeed Butt

AbstractComposites from some novel polyimide and commercial epoxy were prepared aiming to improve the thermal behavior of epoxy resins. Two diamines namely 4-4'-diamino-4''-hydroxytriphenyl methane (DHTM) and 4-4'- diaminotriphenyl methane (DTM) were synthesized by reacting aniline and aldehydes according to a reported method. The synthesized diamines were blended with commercially available epoxy 1, 4-butanedioldiglycidylether (BDDE) to synthesize model epoxy amine networks which were compared with polyimideepoxy composites. The polyimides were synthesized by reaction of these diamines with aromatic anhydride namely 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA). These synthesized polyimides were dispersed in epoxy diamine networks to prepare composites. All the monomers and composites were characterized by making use of various analytical techniques including FTIR, NMR, TGA, DSC and XRD. Presence of hydroxyl group in the diamine helped in better dispersion of polyimide leading to high Tg and high char yield at 600 °C.


2014 ◽  
Vol 14 (8) ◽  
pp. 6422-6426 ◽  
Author(s):  
In Hwan Jung ◽  
Hoyeon Kim ◽  
Wonho Lee ◽  
Byung Jun Jung ◽  
Han Young Woo ◽  
...  

1996 ◽  
Vol 424 ◽  
Author(s):  
Hong-Seok Choi ◽  
Jae-Hong Jun ◽  
Keun-Ho Jang ◽  
Min-Koo Han

AbstractThe material properties of laser-annealed a-Si:Nx films were investigated. The a-Si:Nx films for laser-annealing were deposited by rf plasma enhanced chemical vapor deposition (PECVD) with NH3 and SiH4 gas mixtures. At the 0.35 of NH3/SiH4 ratio, the optical band-gap was abruptly increased to 2.82 eV from 2.05 eV by laser-annealing which indicates that Si-N bonding comes to be notable at that ratio. The electrical conductivity showed the maximum value of 4× 10-6 S/cm at the 0.11 of NH3/SiH4 ratio where the grain growth and the increase of Si-N bonding are optimized for the enhancement of electrical conductivity. The σP/σD ratio which is related to the defects states for photo generation centers was decreased with increasing NH 3/SiH 4 ratio. Our experimental data showed that the optical band gap and electrical conductivity of laserannealed a-Si:Nx films were dominantly affected by the NH3/SiH4 ratio at the 250 mJ/cm2 of laser-annealing energy density.


2018 ◽  
Vol 54 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Sky Paderick ◽  
Matthew Kessler ◽  
Tyler J. Hurlburt ◽  
Steven M. Hughes

Silver gallium sulfide nanocrystals demonstrate tunability for trap-state emission (650 nm) or band gap fluorescence (460 nm).


2002 ◽  
Vol 730 ◽  
Author(s):  
A. Nuñez Rodriguez ◽  
M.T.S. Nair ◽  
P.K. Nair

AbstractAg2S thin films of 90 nm to 300 nm in thickness were deposited at 70°C on glass substrates immersed in a bath mixture containing silver nitrate, sodium thiosulfate and dimethylthiourea. When the films are heated in nitrogen at temperatures 200°C to 400°C, crystallinity is improved and XRD pattern similar to that of acanthite is observed. These films possess electrical conductivity of 10-3 (ohm cm)-1, are photoconductive and exhibit an optical band gap of 1.36 eV. When Ag2S thin film is deposited over a thin film of Bi2S3, also obtained by chemical bath deposition from bismuth nitrate, triethanolamine and thioacetamide, and heated at 300°C to 400°C in nitrogen, a ternary compound, AgBiS2 is formed. This material has an electrical conductivity of 5x10-5 (ohm cm)-1, is photoconductive and possesses optical band gap 0.95 eV.


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