Author
N. Somanathan
Other affiliations: Central Leather Research Institute, Academy of Scientific and Innovative Research
Bio: N. Somanathan is an academic researcher from Council of Scientific and Industrial Research. The author has contributed to research in topics: Thiophene & Electroluminescence. The author has an hindex of 15, co-authored 48 publications receiving 570 citations. Previous affiliations of N. Somanathan include Central Leather Research Institute & Academy of Scientific and Innovative Research.
Topics: Thiophene, Electroluminescence, Side chain, Acrylonitrile, Band gap
Papers
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TL;DR: In this paper, an efficient pure white electroluminescent polymers, obtained by copolymerization of 9,9-dihexylfluorene as a blue host with (E)-2,7-dibromo-9H-fluoren-9-yl-2-cyano-3-(4-(dimethylamino)phenyl) acrylate (FCP) as a yellow emitting covalent dopant with AIEE properties on the main chain of the copolymers, have been designed and synthesized.
Abstract: Aggregation induced emission enhancement (AIEE) is widely regarded as an efficient tool to offset the problem of aggregation caused quenching (ACQ) in luminogens. The ACQ phenomenon in small organic molecules and polymers is detrimental to the performance of OLEDs. Efficient pure white electroluminescent polymers, obtained by the copolymerization of 9,9-dihexylfluorene as a blue host with (E)-2,7-dibromo-9H-fluoren-9-yl-2-cyano-3-(4-(dimethylamino)phenyl) acrylate (FCP) as a yellow emitting covalent dopant with AIEE properties on the main chain of the copolymers, have been designed and synthesized. White light emission was achieved in copolymer FCP 2.5, which contained 2.5% of the AIEE luminogen. Interestingly the copolymers exhibited an enhanced emission upon aggregation even at low compositions of FCP. The enhanced emission in the copolymers is attributed to the supramolecular assembly of the polymeric chains. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) investigations of the monomer and copolymers of FCP revealed the presence of an intramolecular charge transfer (ICT) transition between dimethylamine and the cyanoacrylic acid unit. OLEDs were fabricated using a device with a ITO/PEDOT:PSS/EML/Al structure. White light emitting diodes were fabricated from FCP 2.5 as the emissive layer (EML) and elicited a white electroluminescence with Commission Internationale de l'Eclairage (CIE) coordinate values of (0.33, 0.34). They exhibited a maximum brightness of nearly 9332 cd m−2, a power efficiency of 4.13 lm W−1 and a luminous efficiency of 6.34 cd A−1. Interestingly, the supramolecular ordering in FCP 2.5 considerably reduces the charge trapping which results in a reproducible white light emission.
47 citations
TL;DR: A novel solution processable fluorenone based small molecule with an Aggregation Induced Emission Enhancement (AIEE) property and the presence of the fluore None moiety in FF triggers the AIEE property.
39 citations
TL;DR: In this article, an orange-red emitting multifunctional organic fluorophore consisting of two terminal attachments of push-pull moieties separated by a biphenyl free rotor named BPPTA and its copolymers was reported.
Abstract: Over the past few decades, aggregation-induced emission enhancement (AIEE) has been marked as a powerful tool to offset the bottleneck problem of the aggregation-caused quenching (ACQ) effect in organic light-emitting diodes (OLEDs). However, the application of fluorophores with AIEE properties to enhance the efficiency of non-doped white-light-emitting single-layer polymers is scarce. However, we report herein a novel orange-red emitting multifunctional organic fluorophore consisting of two terminal attachments of push–pull moieties separated by a biphenyl free rotor named BPPTA and its copolymers. A high photoluminescence quantum yield (ΦPL) of 69.1% was observed for BPPTA with strong intramolecular charge-transfer (ICT) and AIEE characteristics. A meticulous investigation showed that the enhanced emission in the solid state was due to the formation of “J-aggregates” with ordered supramolecular self-assembly. Interestingly, BPPTA 0.1 exhibited a unique ordered “spring-like” supramolecular self-assembly and a significant reduction in charge trapping due to its ambipolar charge-transport nature. As a result, pure and efficient white-light emission with Commission Internationale de l’Eclairage (CIE) coordinates of (0.32, 0.33) and maximum luminance, current and power efficiencies of 15 672 cd m−2, 9.30 cd A−1 and 7.98 lm W−1, respectively, were displayed. The DFT and TD-DFT analyses of the BPPTA-gen and copolymer model systems strongly typified the presence of intramolecular charge transfer (ICT) characteristics. This was hitherto one of the best polymer system for dopant–host non-doped single-layer two-colour polymer white organic light-emitting devices (PWOLEDs).
37 citations
TL;DR: This study illustrates the usefulness of quantum-mechanical calculations in understanding the effects of various structural parameters on optical band gap by comparing predicted band-gap values with experimental band gaps obtained from optical-absorption edge.
Abstract: Color tuning by the tailoring of substituents at the 3-position of thiophene is very encouraging, and comparative experimental and theoretical studies proved to be powerful in the search for a suitable design for the above. Since the novel polythiophene-based materials substituted with five-membered/six-membered ring containing sulphur and nitrogen at different positions are proven to be potential candidates for electron-transporting hole blocking functions, the structure-property relationship of these systems have been focused in the present study. Molecular-orbital calculations are applied to obtain the optimized geometries and band gaps of the thiophene oligomers. An oligomeric approach has been implemented for calculating the band gaps, and the theoretically obtained band gaps for the different model compounds are compared. Density-functional theory B3LYP∕6-31G* predicted band-gap values are compared with the experimental band gaps obtained from optical-absorption edge. The predicted values show littl...
34 citations
TL;DR: It has been revealed that the formation of the supramolecular complexes of polyaniline withβ-CD due to host-guest interaction is indispensable for the fabrication of these unique PAni nanostructures, and a suitable β-CD to aniline molar ratio is essential to their exclusive formation.
Abstract: A novel synthesis of “hairy urchin”-shaped polyaniline (PAni) and its surface coverage with nanospikes was achieved from a simple microemulsion polymerization technique in the presence of β-cyclode...
28 citations
Cited by
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TL;DR: This paper presents a meta-analysis of the chiral stationary phase transition of Na6(CO3)(SO4)2, a major component of the response of the immune system to Na2CO3.
Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
5,658 citations
TL;DR: Recent progress in synthesis, characterization, processing and application of polyaniline (PANI) with the focus on the period 2010-2012 is reviewed in this paper, where new insights in the mechanism of formation of molecular/supramolecular PANI structures are discussed.
627 citations
TL;DR: How advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules is reviewed.
Abstract: Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided The advances and shortfalls of various collagen preparations (eg, mammalian/marine extracted collagen, cell-produced collagens, recombinant collagens, and collagen-like peptides) and crosslinking technologies (eg, chemical, physical, and biological) are then critically discussed Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (eg, tissue grafts, biomaterials, cell-assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice
498 citations
TL;DR: In this article, a myofibrillar protein-based films were developed from a film-forming solution based on fish mince and glycerol, sorbitol, or sucrose was incorporated as plasticizer at various concentrations.
Abstract: Myofibrillar protein-based films were developed from a film-forming solution based on fish mince. Glycerol, sorbitol, or sucrose was incorporated as plasticizer at various concentrations. The increase in film solubility in water with plasticizer content reflect plasticizer solubility in water. Solubility in water of protein network is not significantly affected by plasticizer concentration whatever the plasticizer. On the other hand, plasticization of myofibrillar protein-based films induced large decreases in film strength and elasticity and increases in deformation properties and water vapor permeability. No significant difference was observed in variations of functional properties as a function of plasticizer type when plasticizers were introduced at the same molecular contents, due to the structural similarities between glycerol, sorbitol, and sucrose. Keywords: Biopackaging; myofibrillar proteins; plasticizer; functional properties
288 citations
TL;DR: In this article, Diethanolamine and triethanolamine were selected among several low and high molecular weight polyols and amines tested as potential plasticizers of wheat gluten film.
256 citations