@article {46648, title = {Ultrahigh sensitive carbon-based conducting rubbers for flexible and wearable human-machine intelligence sensing}, journal = {Advanced Materials Technologies}, volume = {5}, year = {2020}, month = {DEC}, pages = {2000690}, type = {Article}, abstract = {

The wearable strain sensors with multifunctional applications can fuel the rapid development of human-machine intelligence for various sectors like healthcare, soft robotics, and Internet of Things applications. However, achieving the low-cost and mass production of wearable sensors with ultra-high performance remains challenging. Herein, a simple, cost-effective, and scalable methodology to fabricate the flexible and highly sensitive strain sensors using carbon black and latex rubbers (LR) is presented. The LR-based strain sensor demonstrates excellent flexibility, fast response (approximate to 600 ms), ultra-high sensitivity (maximum gauge factor of 1.2 x 10(4) at 250\% strain), and long-term stability over 1000 cycles. The LR-based strain sensors are sensitive to monitor subtle human motions such as heart pulse rate and voice recognition along with high-strain human joint operations. Additionally, the sensing mechanism of LR bands is investigated by surface topographies and electromechanical response under various strained/unstrained conditions. Further, a smart glove-based sensor module made of LR strain bands with an Arduino reader for the human-machine intelligence device for non-verbal communication in military applications is demonstrated.

}, keywords = {conducting rubbers, gauge factor, human\&\#8211, machine interfacing, voice recognition, wearable strain sensors}, issn = {2365-709X}, doi = {10.1002/admt.202000690, Early Access Date = NOV 2020}, author = {Ajeev, Arya and Javaregowda, Bharathkumar H. and Ali, Ashik and Modak, Mrudul and Patil, Shreya and Khatua, Saumyakanta and Ramadoss, Marimuthu and Kothavade, Premkumar Anil and Arulraj, Arul Kashmir} } @article {46731, title = {Unsymmetrical squaraine dyes for dye-sensitized solar cells: position of the anchoring group controls the orientation and self-assembly of sensitizers on the TiO2 surface and modulates its flat band potential}, journal = {Journal of Physical Chemistry C}, volume = {124}, year = {2020}, month = {AUG}, pages = {18436-18451}, type = {Article}, abstract = {

The position of the anchoring group is systematically changed with a series of alkyl group wrapped donor-acceptor-donor (D-A-D) based squaraine dyes, 4-SQ to 7-SQ, for the use in dye-sensitized solar cells (DSSCs). By this approach, the orientation as well as the self-assembly of the sensitizers can be controlled on the semiconducting TiO2 surface. All of the dyes functionalized with hydrophobic alkyl groups at sp(3)-C and N atoms of the indoline units that is far away from the TiO2 surface to control the self-assembly of dyes and passivate the surface. Controlling both the orientation as well as the self-assembly of the sensitizers synergistically enhances the V-oc of the DSSC device by imparting the dipole moment on the TiO2 surface and minimizing the interfacial charge recombination process of electrons from TiO2 to the oxidized electrolyte, respectively. Further, the presence of a meta-carboxyl group with respect to the N atom of the indoline donor unit for the dyes 4-SQ and 6-SQ makes them nonconductive for the charge injection process, which sheds light on the importance of through-space electron transfer for the device performance. Emission from the relaxed twisted state was found to be a deactivation pathway for 4-SQ on TiO2 and ZrO2, which revealed the importance of structural factors that promote spatial interaction between the sensitizer and metal oxide surface. Computational studies showed the systematic changes in the dipole moment for the sensitizers 4-SQ, 5-SQ, and 6-SQ upon anchoring to the TiO2 surface. The DSSC device performance varied with the position of anchoring groups in the sensitizers. The DSSC device performance of 5-SQ indicates a J(sc) value of 11.35 mA cm(-2), V-oc of 0.698 V, and ff of 77\% corresponding to a power conversion efficiency of 6.08\% in the presence of 3 equiv of coadsorbent CDCA, which is nearly 1.5 times higher than 6-SQ (V-oc 0.7 V, J(sc) 7.76 mA cm(-2), ff 76\%, and eta 4.14\%) and 2.6 times higher than 4-SQ (V-oc 0.658 V, J(sc) 4.42 mA cm(-2), ff 78\%, and eta 2.28\%). IPCE studies revealed the importance of orientation for the charge injection and self-assembly of dyes, as devices with 5-SQ and 6-SQ as a sensitizer showed 94 and 77\% response at 578 nm, respectively, which correspond to the aggregated structure of the dye. Mott-Schottky and IPCE experiments showed that the orientation of sensitizers could modulate the V-oc due to the shift in the flat band potential of TiO2.

}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.0c05176}, author = {Singh, Ambarish Kumar and Maibam, Ashakiran and Javaregowda, Bharathkumar H. and Bisht, Rajesh and Kudlu, Ashwath and Krishnamurty, Sailaja and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {47428, title = {Partially bio-based triarylamine-containing polyimides: synthesis, characterization and evaluation in non-volatile memory device applications}, journal = {European Polymer Journal}, volume = {147}, year = {2021}, month = {MAR }, pages = {110327}, type = {Article}, abstract = {

A new triarylamine-containing diamine, viz. 4, 4{\textquoteright}-diamino-4 {\textquoteleft}{\textquoteright} pentadecyltriphenylamine was synthesised starting from cashew nut shell liquid (CNSL) - a non-edible by-product of cashew processing industry. Three new partially bio-based triarylamine-containing polyimides were synthesised by one-step high temperature solution poly-condensation of 4, 4{\textquoteright}-diamino-4 {\textquoteleft}{\textquoteright} pentadecyltriphenylamine with aromatic dianhydrides, namely, 3,3{\textquoteright},4,4{\textquoteright}-biphenyltetracarboxylic dianhydride (BPDA), 4,4{\textquoteright}-oxydiphthalic anhydride (ODPA) and 4,4{\textquoteright}-(hexa-fluoroisopropylidene) diphthalic anhydride (6-FDA). Polyimides were determined to be of reasonably high molecular weights as inherent viscosity and number average molecular weights (M-n, Polystyrene standard) values were in the range 0.54-0.60 dL g(-1) and 26,800-43,500 g mol(-1), respectively. Polyimides exhibited excellent solubility in common organic solvents and film-forming nature along with reasonably good thermal properties as indicated by temperature for 10\% weight loss (T-10) and glass transition temperatures (T-g) which were in the range 418-447 and 165-225 degrees C, respectively. The optical and electrochemical band-gap values were in the range of 1.95-1.98 eV and 1.671-1.745 eV, respectively. Among triarylamine-containing polyimide devices, BPDA-based device showed acceptable current-voltage and non-volatile memory properties such as the endurance of 500 cycles and 1000 s of retention time. The conduction mechanism developed in the memory devices was also explored and was found to follow Ohmic and Schottky conduction mechanisms.

}, keywords = {Bio-based polyimides, CNSL, Memory device, pentadecyl, Triarylamine}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2021.110327}, author = {Chatterjee, Deepshikha and Jadhav, Uday A. and Javaregowda, Bharathkumar H. and Dongale, Tukaram D. and Patil, Pramod S. and Wadgaonkar, Prakash P.} } @article {49137, title = {Modular TiO2-squaraine dyes/electrolyte interface for dye-sensitized solar cells with cobalt electrolyte}, journal = {Chemphotochem}, volume = {7}, year = {2023}, month = {APR}, type = {Article}, abstract = {

Strategies to diminish both charge recombination and aggregation of dyes on the photoanode by functionalizing the sensitizer with alkyl groups is the best approach to achieve high dyesensitized solar cell (DSSC) efficiency. Development of such a photoanode with NIR-active dyes which is compatible with a cobalt electrolyte is important to enhance the photovoltaic performance. In this report, alkyl-group-wrapped donor-acceptor-donor (D-A-D) based unsymmetrical squaraine dyes have been used for DSSC device characterization with a cobalt electrolyte. Surface passivation of photoanode was varied systematically by the extent of functionalization with alkyl groups to avoid charge recombination. DSSC device performance of 5.92\% was achieved for an alkyl-group-wrapped squaraine dye with a cobalt electrolyte. Hence, appending the alkyl groups on the donor unit of squaraine dyes helps passivating the photoanode, whereas introducing hydrophilic groups provides a leaky surface where oxidized electrolyte species reach the titanium-metal-oxide surface which promotes the charge recombination process.

}, keywords = {counter-electrode, DSSC device efficiency, Dye-sensitized solar cells, Electrolytes, unsymmetrical squaraine dye}, issn = {2367-0932}, doi = {10.1002/cptc.202200171}, author = {Singh, Ambarish Kumar and Sudhakar, Vediappan and Javaregowda, Bharathkumar H. and Bisht, Rajesh and Krishnamoorthy, Kothandam and Nithyanandhan, Jayaraj} } @article {48290, title = {Organic field effect transistors comprising copolymers synthesized without structure-directing moieties with enhanced carrier mobility}, journal = {ACS Applied Electronic Materials}, volume = {5}, year = {2023}, month = {APR}, pages = {2338-2344}, type = {Article}, abstract = {

Conjugated materials are synthesized by C-C bond formation reactions. Trimethyltin and boronic acid are two widely used structure-directing moieties. While using the ethynyl moiety as a part of the monomer, additional structure-directing moieties are not needed. However, ethynylene will be part of the conjugated material. Often, the polymers with an ethynylene moiety negatively impact the polymers{\textquoteright} properties. However, the ethynylene moiety could minimize the dihedral angle if the monomer has steric functionalities. For example, BODIPY is an attractive monomer due to its high molar extinction coefficient, partial quinoidal character, and high quantum yield. However, materials based on BODIPY exhibited poor charge carrier mobility due to steric hindrance generated by four methyl groups. Herein, we copolymerize BODIPY with ethynylene comprising i-indigo and thieno-i-indigo. The copolymer with thieno-i-indigo showed increased molecular weight and significantly reduced band gap compared to the copolymer with i-indigo. The copolymer with i-indigo showed immeasurably low hole transport mobility. On the other hand, the copolymer with thieno-i-indigo exhibited 0.003 cm2V(-1) s(-1). These measurements were made using field effect transistors. We also measured the charge carrier mobility using the space charge-limited current method. Both copolymers exhibited a mobility of 10(-3) cm(2) V-1 s(-1).

}, keywords = {acetylene linkage, BODIPY, field effect transistor, iso-indigo, Sonogashira coupling, thienoisoindigo}, doi = {10.1021/acsaelm.3c00160}, author = {Swain, Gitanjali and Javaregowda, Bharathkumar H. and Dambhare, Neha V. and Krishnamoorthy, Kothandam} } @article {49245, title = {MOFite: a high-density lithiophilic and scalable metal-organic framework anode for rechargeable lithium-ion battery}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {63}, year = {2024}, month = {OCT }, type = {Journal Article}, keywords = {conjugated MOF, Energy storage, lithium ion battery, Metal-organic framework, scalable synthesis}, issn = {1433-7851}, doi = {10.1002/anie.202409256}, author = {Gaber, Safa and Mohammed, Abdul Khayum and Javaregowda, Bharathkumar H. and Martinez, Jose Ignacio and Sanchez, Pilar Pena and Gandara, Felipe and Krishnamoorthy, Kothandam and Shetty, Dinesh} } @article {49212, title = {Shuttle balance between lithiophilic functionalities substituted on conjugated polymers to improve lithium-ion diffusion and cycling stability of batteries}, journal = {Macromolecules}, volume = {57}, year = {2024}, month = {AUG}, pages = {7830-7840}, type = {Article}, abstract = {

Herein, we report the design and synthesis of i-Indigo and trans-1,2-di(2-thienyl)ethylene (TVT) comprising copolymers with various side chains that are used as anode-cum-binder in Li-ion batteries. The TVT disrupts the crystallinity, and the i-Indigo renders the handle for unsymmetrical substitution. Polymer P1 comprises alkyl chains on i-Indigo, whereas P2 comprises an alkyl chain and a chain with a urethane moiety as another side chain. Polymer P3 comprises i-Indigo with a urethane moiety and triethylene glycol as side chains. The i-Indigo in P4 is substituted with triethylene glycol and alkyl chains as side chains. These polymers were found to be amorphous with pi-pi stacking due to the extremely small torsional angle imparted by TVT moieties. All of these polymers showed comparable specific capacity while used as an anode in Li-ion batteries due to the presence of a common conjugated backbone. However, the battery metrics varied significantly while the current density of the batteries varied between 0.1 and 2.0 A g(-1). P1 and P2 showed a very close recovery of specific capacity at 0.1 A g(-1) before and after various current densities. However, polymers P3 and P4 did not recover from the specific capacity fading due to the presence of triethylene glycol side chain that degraded. Polymer P2 with an alkyl side chain and a chain with a urethane moiety showed stable performance over 2000 charge-discharge cycles. Contrary to this, the stability of polymers with triethylene glycol side chains decreased over 2000 charge-discharge cycles. Polymer P2 with a urethane side chain also showed improved Li-ion diffusion because the urethane moiety facilitated better Li-ion transport.

}, issn = {0024-9297}, doi = {10.1021/acs.macromol.4c01036}, author = {Kargude, Radhakisan and Javaregowda, Bharathkumar H. and Palani, Sathishkumar and Singh, Anup K. and Krishnamoorthy, Kothandam} } @article {49340, title = {Synergistic effect of lactam and pyridine nitrogen on polysulfide chemisorption and electrocatalysis in lithium sulfur batteries}, journal = {ACS APPLIED MATERIALS \& INTERFACES}, volume = {16}, year = {2024}, month = {AUG }, pages = {42059-42068}, keywords = {Li-S battery, phenyl-diketopyrrolopyrrole, pyridine-diketopyrrolopyrrole}, issn = {1944-8244}, doi = {10.1021/acsami.4c05128}, author = {Javaregowda, Bharathkumar H. and Kargude, Radhakisan and Birajdar, Sarika and Shivankar, Bhavana and Krishnamurty, Sailaja and Jones, Lathe A. and Caruso, Rachel A. and Krishnamoorthy, Kothandam} }