Electropolymerization studies of conjugated monomers and their biosensor applications

Dr Supreetha has used an effective technique called electropolymerization to synthesise the highly stable Conjugated Polymer Films directly on the surface of various conducting substrates such as Glassy Carbon (GC), Indium Tin Oxide (ITO) and Flexible ITO (FITO) using a range of bifunctional and trifunctional monomers. These Electrodeposited conducting polymer thin films are directly utilised for capturing various biomolecules due to higher surface area and greater sensitivity. A customised 3D Microporous polymer film is evidenced to detect clinically relevant Ovarian Cancer Biomarker miRNA and Nucleic Acid. This thesis has demonstrated the development of highly sensitive Genosensing Platform

Investigation of thiophene flanked diketopyrrolopyrrole monomers with straight and branched alkyl chains and their electropolymerization study

Diketopyrrolopyrrole (DPP) is a critically important building block that has gained importance in the organic electronics community because of its wide applicability in various devices. In this work, the thiophene flanked DPP moiety attached to alkyl chains of various lengths (this includes straight octyl and branched ethyl hexyl units) has been used as the monomer for electropolymerization. This paper focuses on the study of optical, thermal, solid state ordering and electrochemical properties of these electron deficient monomers using various characterization techniques such as UV–Vis spectrometry (UV), photo-luminescence spectroscopy (PL), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), cyclic voltammetry (CV), as well as ab initio modeling. These monomers exhibit broad absorption spectra from the ultraviolet (280–400 nm) to visible (400–600 nm) regions and emission spectra between 560 and 610 nm. The band gaps of these monomers were calculated to be in the range of 2.00–2.20 eV. These monomers were electropolymerized by scanning the potential between −0.5 and 2.0 V versus ferrocene for up to 50 cycles on a glassy carbon electrod

Naphthalene flanked diketopyrrolopyrrole: a new conjugated building block with hexyl or octyl alkyl side chains for electropolymerization studies and its biosensor applications

Diketopyrrolopyrrole (DPP) is one of the most fascinating organic dyes, and has gained significant attention in the organic electronic community in recent times. Due to their outstanding semiconducting properties, DPP-based small molecules and polymers can be used as active semiconductor thin films for various high performance electronic devices. However, although several flanking groups attached to the DPP backbone have been reported in the literature for DPP molecules, there is little study about the effect of fused rings flanked on both sides of the DPP core. Recently our group reported for the first time a naphthalene-flanked DPP as a new DPP family member. In this work, we have performed electropolymerization studies on a newly synthesized naphthalene flanked DPP core with two alkyl chains, hexyl (H-DPPN) and octyl (O-DPPN), as conjugated monomers. Electrochemical studies have been carried out on glassy carbon (GC) and indium tin oxide (ITO) electrodes by using repetitive cyclic voltammetry (CV) as the deposition technique for up to 50 cycles. The concentration of H-DPPN and O-DPPN solution in dichloromethane was found to be a key parameter when optimizing conditions for obtaining an electropolymerised thin film, although other parameters such as the electrolyte, potential range, number of cycles, and the nature of the electrode all play a role in successful thin film formation. The electropolymerized thin films were characterised using UV-Vis spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photon spectroscopy (XPS) and surface profilometry. We found that each monomer produced different film morphologies on glassy carbon and ITO electrodes. We believe that electropolymerized poly(H-DPPN) and poly(O-DPPN) thin film electrodes could be used for various applications such as studying redox reactions and bio-sensing

Naphthalene flanked diketopyrrolopyrrole: A new DPP family member and its comparative optoelectronic properties with thiophene- and furan-flanked DPP counterparts

Diketopyrrolopyrrole (DPP) has been one of the most promising building blocks for constructing organic semiconducting materials used in organic field-effect transistors (OFET). As we have known, extended p-conjugated structure can facilitate intermolecular orbital coupling which determines the magnitude of the charge transfer integral and thus the charge transport in devices. What is more, better intramolecular charge transport and intermolecular charge hopping depend on more superior morphology of the conjugated materials in thin film that is influenced by flexible substitutions. Based on the above principles, it is worthy designing and synthesizing fused ring flanked DPP monomers with alkyl chains to exploit their potential use in OFET. In this work, we first synthesized and characterized a new DPP derivative, naphthalene flanked DPP with butyl-octyl side chain (BO-DPPN). When comparing with its thiophene-and furan-flanked DPP analogues using the same common alkyl chain, BO-DPPN appears as most suitable for OFET applications. For example, DSC analysis demonstrates its high degree of crystallinity, UV-Vis spectra show a strong aggregation in solid state, XRD pattern indicates its tight and long-range ordered lamellar packing. As expected, the OFET devices function well when using BO-DPPN directly as active semiconductor and an impressive hole mobility of 0.0126 cm(2) V-1 s(-1) was observed with a bottom-contact/top-gate architecture using a solution processable approach indicating its promising potential for use in organic electronics.11Nsciescopu