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Author: search.filters.author.Nikhil, P.P.

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    investigation on photophysical and third–order nonlinear optical properties of novel thermally–stable thiophene–imidazo [2,1-b][1,3,4] thiadiazole based azomethines
    (Elsevier, 2019) Kakekochi, Viprabha; Udayakumar, D.; Nikhil, P.P.; Keloth, Chandrasekharan
    The use of π–conjugated semiconducting materials in flexible and large–area optoelectronic devices is proliferated worldwide owing to the easy structural modifications and solution processability possible, leading to the change in opto–electronic properties. In this context, new class of thiophene and imidazo [2,1-b][1,3,4] thiadiazole (ITD) based conjugated azomethines (TI1–TI3) were designed and synthesized. The photophysical and electrochemical properties of the synthesized azomethines (TI1–TI3) were investigated experimentally, which were further validated with the aid of theoretical calculations. Further, the azomethines TI1 and TI2 were subjected to Z–scan analysis to study the nonlinear optical (NLO) properties. The molecules exhibited effective two photon absorption (TPA) with the large nonlinear absorption coefficient (βeff) of the order of 10−10 m W−1. The planar structure of TI1 furnished a better interaction between donor and acceptor moieties and extended the π–conjugation, providing an improved βeff (0.81 × 10−10 m W−1) to TI1 compared to that of TI2 (0.55 × 10−10 m W−1). From the results it is inferred that the molecules could be of potential materials to be used in efficient photonic devices.
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    Effects of substituents on the enrichment of the optical limiting action of novel imidazo[2,1-: B] [1,3,4]thiadiazole fused thiophene-based small molecules
    (2019) Kakekochi, V.; Udayakumar, D.; Nikhil, P.P.; Chandrasekharan, K.
    The imidazo[2,1-b][1,3,4]thiadiazole (ITD) ring is a fused, planar aromatic heterocyclic system consisting of four heteroatoms with a bridgehead nitrogen atom. In this study, three new donor-acceptor-donor (D-A-D)-type organic molecules (ThITD1-ThITD3) were designed and synthesized, wherein ITD was an electron acceptor unit and the thiophene/phenyl moieties were electron donor units that produced a D-A-D configuration. The thiophene-ITD core structure comprises three different groups viz., thiophene-2-acetonitrile (ThITD1), phenylacetonitrile (ThITD2) and rhodanine-3-acetic acid (ThITD3), and the effect of substituents on the optical and electrochemical properties have been discussed based on structural modifications. The third-order nonlinear optical (NLO) properties analyzed by the Z-scan technique reveal that the molecules exhibit effective two photon absorption (TPA) with ThITD3 possessing substantially higher effective TPA coefficient (?eff) than ThITD1 and ThITD2, which is comparable to the reported ?eff values. The results unravel that ITD as an acceptor with an appropriate ?-linker will be a promising candidate for application in the field of optoelectronics/photonics. Herein, the thiophene-ITD ring system was explored for NLO applications and reported for the first time. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.