Contents lists available at ScienceDirect Materials Science & Engineering B journal homepage: www.elsevier.com/locate/mseb Preparation, characterization and electrical properties of alkali metal ions doped co-polymers based on TBF Rudramani Tiwari a , Ekta Sonker a , Devendra Kumar a , Krishna Kumar b , Pubali Adhikary a , S. Krishnamoorthi a, ⁎ a Department of Chemistry, Centre of Advanced Studies, Institute of Science, Banaras Hindu University, Varanasi 221005, India b Department of Chemistry and Environmental Science, Madan Mohan Malaviya University of Technology, Gorakhpur 273010, India ARTICLE INFO Keywords: Alkali metal doping Solid polymer electrolytes Semiconducting polymer Electrical properties Energy storage materials ABSTRACT Click reaction method led to the formation of polymeric structures with 1,2,3-triazoles. By applying metho- dology we have synthesized thiophene-bisphenyl fluorene (TBF) based co-polymer, containing triazole ring on its back-bone and doped it with Li + , Na + and K + metal ions. Upon doping with these metal ions, the non- conducting (TBF) polymer becomes ionic conducting in nature i.e. (TBF) n- (Li + ) n , (TBF) n- (Na + ) n , and (TBF) n- (K + ) n . Among the all doped polymers, K + doped polymer shows best conductivity (con- ductivity ~ 2.5 × 10 -4 S/cm), low band gap, low activation energy, dielectric properties, capacitance, dielectric permittivity loss, dielectric loss and electrical modulus. These properties of solid polymeric electrolytic materials make it more useful in the field of organic voltaics. 1. Introduction Efficient use and storage of energy is the basic requirement for humanity to have better life This requires high energy source and sto- rage devices e.g. batteries that have low energy losses during storage, electrical charging and discharging, and batteries with long lifetimes with minimum production and disposal costs. Solid polymer electrolyte materials (SPEs) are very useful, because of their application in high energy density batteries [1], fuel cells [2], supercapacitors [3], sensors [4] and electro-chromic devices [5] and other electrochemical devices for the development of high capacitance gate dielectric materials to boost OTFT currents and enable lower voltages operating [6]. The main objectives in this area are the development of polymer electrolyte materials with high ionic conductivity, better stability, high efficiency and enhancing the ionic conductivity of SPEs. SPEs have been useful as energy storage materials, due to the higher power density, compared to the Li-ion batteries [7] SPEs show faster charge–discharge cycles and higher energy storage [8] and have high power supply capability [9]. These properties of SPEs materials bridge the gap be- tween the conventional capacitor and the battery with a long life time with better efficiency and environment-friendly operation [10]. Capa- citors have been developed that give hundreds to thousands of Farads and these are usually known as super-capacitors or ultra-capacitors [11]. Various type of super-capacitors are reported previously such as electrochemical double-layer capacitor (EDLC) [12], pseudo-capacitor as conducting polymer (CP) [13], CP aqueous hybrids [14], lithium batteries [15] and fuel cells [16]. The concept of ‘bridging the gap’ with batteries to form conducting-polymer-based super-capacitors with su- perior specific energy has been reported by Graeme A. Snook et al. in 2010 [17]. Polymer Electrolytes have been reported by Wolfgang H. Meyer for Lithium-Ion Batteries [18]. Ionically conducting polymer electrolytes enhanced lithium-battery efficiency and thereby enabled the fabrication of compact, flexible, solid-state structures discovered ionic conductivity in Na complex in 1975 [19]. Flexibility of electro- active polymeric materials, have potential to enable major advances in for electronic applications [20]. Flexible materials provide high charge storage with low resistivity to achieve high capacitance performance [21]. It is well known that the high channel currents are formed by reversible electrochemical doping of the semiconducting polymer film. Heteroaromatic compounds like thiophene and pyrrole etc. were used for developing various type of semiconducting polymeric systems which act as electron transporter due to complete conjugated double bonds in the system [22]. The hetero atoms which are easily oxidized help in the doping process. On the other hand, fluorene also has properties which are utilized in the field of OTFTs, organic photo- voltaics, organic memories, sensors, etc. The effects of one-dimensional architectures on the matrix provide multi-layer formation thus pro- viding a large incentive for study [23]. In order to readily this layers https://doi.org/10.1016/j.mseb.2020.114687 Received 31 March 2020; Received in revised form 11 June 2020; Accepted 12 August 2020 ⁎ Corresponding author. E-mail address: skmoorthi@bhu.ac.in (S. Krishnamoorthi). Materials Science & Engineering B 262 (2020) 114687 0921-5107/ © 2020 Published by Elsevier B.V. T