M. Ramar; S. S. Rawat; R. Srivastava; S. K. Dhawan; C. K. Suman
Abstract
The impact of cross linking chain of N, N’-bis (napthalen-|-y|)-N, N’-bis(phenyl)-benzidine (NPB) was studied for opto-electrical properties having focus on temperature dependent transport properties. The Spiro structured NPB compound is closed in itself and the thin film surface roughness ...
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The impact of cross linking chain of N, N’-bis (napthalen-|-y|)-N, N’-bis(phenyl)-benzidine (NPB) was studied for opto-electrical properties having focus on temperature dependent transport properties. The Spiro structured NPB compound is closed in itself and the thin film surface roughness is less in comparison to NTNPB compounds. Both absorptions and photoluminence shows a shift of 10 nm towards higher wavelength in case of cross linked spiro structured compound. The mobility calculated in SCLC region for NT and Spiro NPB was 1.32×10 -7 and 3.3x10 -7 cm 2 V -1 s -1 , respectively. Both the compounds show single relaxations and can be modeled as an RC equivalent circuits. The dc conductivity for both the compounds was explained by Mott’s VRH models showing 3D transport mechanism. The hopping distance for NT and Spiro NPB compounds is 0.8 and 0.5 nm, respectively. The hopping conduction process can be explained clearly using correlated barrier hopping model. The cross linking of the compounds shows two orders of less density of states.
Rakesh Kumar; Seema Joon; Avanish P. Singh; Brij P. Singh; S. K. Dhawan
Abstract
In response to the striking research activity and publications in fabrication of multifunctional materials, the present work is an attempt to fabricate processible composite sheets of poly (o-anisidine)-carbon fiber (PoACF) by a facile, low cost method and find their use in electromagnetic interference ...
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In response to the striking research activity and publications in fabrication of multifunctional materials, the present work is an attempt to fabricate processible composite sheets of poly (o-anisidine)-carbon fiber (PoACF) by a facile, low cost method and find their use in electromagnetic interference (EMI) shielding in X-band (8.2-12.4 GHz). PoACF composite is synthesized by in-Situ oxidative emulsion polymerization and transformed into thin sheets by compression molding technique using different ratio of phenolic novolac resin as a binder. The prepared PoACF composites and sheets are characterized by SEM, TGA, UV-vis, & FT-IR techniques. PoACF sheets have conductivity of the order of 10 -3 to 10 -1 S/cm and maximum shielding effectiveness of 32.57 dB at 4 mm thickness. These sheets have flexural strength between 18.82 to 41.28 MPa. The sheets of PoACF composite have sufficient thermal as well as mechanical stability and may be accepted as an economical material for EMI shielding application.
