@article {48087,
	title = {Instabilities as the origin of large-area self-assembled and aligned organic semiconductor nanocrystals},
	journal = {ACS Applied Electronic Materials},
	volume = {4},
	year = {2022},
	month = {APR},
	pages = {1815-1822},
	type = {Article},
	abstract = {<p>
	Aligned nanocrystals of organic semiconductors (OSCs) are highly desirable for electronic devices and biomedical and photonic applications. Solution-based wet processing routes have the potential to produce aligned nanocrystals over large areas in small time frames. Herein, we demonstrate that by optimizing the hydrodynamic evaporative processes, controlled long-range crystalline assemblies of OSCs can be achieved (longest nanocrystal similar to 3 mm) purely through physical processes: namely, from fingering instabilities. Self-assembly is achieved here without strong noncovalent interactions such as hydrogen-bonding interactions. Experimentally our approach involves just placing a drop of a solution on an inclined substrate. Nanocrystals with widths of 300-800 nm and lengths of millimeters (length/width aspect ratios \&gt;10(5)) are formed in less than 2-8 s. A hydrazine chemiresistive sensor based on the aligned crystalline patterns show unprecedented responsivity (similar to 10(-6)), 2 orders greater than those of stick-slip patterns. Finally, experimental parameters that need optimization to achieve nanocrystal patterns are investigated in detail and pointers to fabricate such OSC nanocrystals are provided.</p>
},
	keywords = {aligned fibers, diketopyrrolopyrrole, fingering instability, nanocrystal arrays, naphthalenediimide, organic semiconductors},
	doi = {10.1021/acsaelm.2c00061},
	author = {Venugopalan, Vijay and Jain, Bhanprakash and Mahale, Rajashree Y. and Subramani, Kumar and Krishnamoorthy, Kothandam}
}
@article {49676,
	title = {Long cycling stability imparted to li-ion batteries by conjugated polymers with low dihedral angles and high electron density on functional groups},
	journal = {ACS Applied Polymer Materials},
	volume = {7},
	year = {2025},
	month = {JUN},
	pages = {7719-7728},
	type = {Article},
	abstract = {<p>
	In conjugated polymers, dihedral angles at bonds connecting their monomers impact the polymers{\textquoteright} properties such as the packing of the polymer chains, bandgap, and conductivity. These properties are expected to impact the performance of rechargeable Li-ion batteries because the Li-ion transport and conductivity of the polymers are two important parameters. To understand this, we designed and synthesized two polymers with two different dihedral angles. The polymer, Poly(EDOT-DPP), comprising diketopyrrolopyrrole (DPP) and ethylenedioxythiophene (EDOT) as monomers, showed a low dihedral angle of 2 degrees. On the other hand, the polymer, Poly(EDOT-i-Ind), comprising EDOT and i-Indigo (i-Ind) showed a dihedral angle of 17 degrees. Density functional theory (DFT) studies showed that the electron density at the carbonyl moiety of EDOT-DPP is higher than that of EDOT-i-Ind. This resulted in a higher Li+ binding energy of -3.665 eV for EDOT-DPP and a lower Li+ binding energy of -3.464 eV for EDOT-i-Ind. Battery electrodes were fabricated using either Poly(EDOT-DPP) or Poly(EDOT-i-Ind) with multiwalled carbon nanotubes as conducting fillers in the absence of any binders. The Li+ ion diffusion coefficient ( D Li + ) measured for the as prepared batteries based on Poly(EDOT-DPP) was found to be 3.9 x 10-19 cm2/s, which is slightly higher than that found for Poly(EDOT-i-Ind). However, after 2000 cycles, the D Li + increased by about two orders of magnitude for both polymers. Due to the low dihedral angle in the case of Poly(EDOT-DPP), the D Li + was found to be 21\% higher than that of Poly(EDOT-i-Ind). The higher binding of Li+ ions with Poly(EDOT-DPP) and Li+ ion diffusion improved the specific capacity and cycling performance of batteries fabricated with this polymer. At a current density of 0.2 A/g, Poly(EDOT-DPP) showed a 39\% higher specific capacity than the Poly(EDOT-i-Ind) polymer after 2000 cycles. The batteries also showed stable performance over 2000 cycles with an insignificant decrease in specific capacity.</p>
},
	keywords = {dihedral angle, diketopyrrolopyrrole, i-indigo, Li-ion battery, Li-ion transport},
	issn = {2637-6105},
	doi = {10.1021/acsapm.4c04072},
	author = {Kargude, Radhakisan and Srinivasalu, Hari Haran and Devasia, George and Krishnamurty, Sailaja and Krishnamoorthy, Kothandam}
}
