02736nas a2200229   4500008004100000022001400041245010700055210006900162260000900231300001400240490000700254520195100261100002702212700001702239700001702256700001402273700002002287700001702307700002402324700002802348856013002376       2024                        eng d  a2050-748800aWater-chain mediated proton conductivity in mechanically flexible redox-active organic single crystals0 aWaterchain mediated proton conductivity in mechanically flexible  cMAR   a5866-58740 v123 a<p>
	Investigating electrochemical features of proton-conducting organic crystalline materials is relevant in developing efficient energy storage and conversion devices. However, the poor structural flexibility of the crystalline materials at the molecular level often impedes hydrogen bond reorganization of the proton carriers during proton migration, ultimately leading to low ionic conductivity. Here, we report crystals of azobenzene, functionalized with dipicolylamine at both ends (Azo-DPA), which contain an extended hydrogen-bonding network with water molecules in its structure. Interestingly, the crystals display remarkable mechanical flexibility explicitly probed by the nanoindentation technique. The mechanically flexible neutral organic crystals devoid of any acidic moieties (-COOH, -PO3H2, etc.) within the system, exhibit promising proton conductivity (1.63 x 10-4 S cm-1 at 30 degrees C under 95% relative humidity) which is almost 100 times better compared to the neutral organic systems reported to date. Mechanically flexible redox-active crystalline organic material (Azo-DPA) capable of impressive proton conduction was employed as an electrode material for the first time in an aqueous battery containing Zn2+ ions. The experimental and theoretical studies on the charge storage mechanism revealed the redox activity of the azo (-N 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 N-) centers involving reversible insertion/extraction of protons and Zn2+ ions. Ultimately, the electrode displayed a specific capacity similar to 49 mA h g-1 with almost 100% retention after 1400 cycles, encouraging the scope of redox-active organic crystalline materials for energy storage applications. Investigating the electrochemical features of proton-conducting flexible organic crystalline materials is crucial for the development of efficient energy storage and conversion devices.</p>
1 aHossain, Munshi, Sahid1 aGhosh, Meena1 aMondal, Amit1 aAjmal, P.1 aSaha, Monochura1 aReddy, Malla1 aKurungot, Sreekumar1 aBandyopadhyay, Subhajit  uhttps://library.ncl.res.in/content/water-chain-mediated-proton-conductivity-mechanically-flexible-redox-active-organic-single02203nas a2200241   4500008004100000245009800041210006900139260000800208300000900216490000700225520141400232100001801646700002101664700002201685700002001707700001701727700001701744700001701761700002301778700001801801700001701819856012501836       2026                        eng d00aFast self-healing in a layered molecular crystal mediated by stress-induced symmetry breaking0 aFast selfhealing in a layered molecular crystal mediated by stre  cFEB  a25250 v173 a<p>
	In recent years, symmetry-breaking has emerged as a powerful tool for significantly altering various physical properties in 2D layered materials. However, the breaking of symmetry by means of mechanical stress in organic crystals remains elusive. Here, we demonstrate a simple approach to engineer symmetry-breaking through mechanical stress fields in a layered molecular crystal, resulting in autonomous and fast self-healing under ambient temperature and pressure conditions. Fracture mechanics analysis reveals that the crystal adheres to an elasto-plastic model, with formation of a plastic zone at the crack tip, which prevents further crack propagation, facilitating the self-healing process. Spatially resolved Raman mapping reveals that the crack formation is accompanied by a distinct symmetry-breaking mechanism at the microstructural level. A six-fold increase in non-linear second harmonic (SH) activity, triggered by mechanical perturbation, further validates the local symmetry breaking in an otherwise centrosymmetric crystal. Furthermore, symmetry is restored following successful healing, as evidenced by the disappearance of the SH signal in the healed regions. This study not only broadens the scope of self-healing mechanisms viable in molecular materials but also offers key insights into the role of symmetry breaking and its potential for related technological applications.</p>
1 aGhosh, Ishita1 aBiswas, Rabindra1 aTanwar, Manushree1 aBhunia, Surojit1 aDas, Kaustav1 aTorris, Arun1 aMondal, Amit1 aRaghunathan, Varun1 aKumar, Rajesh1 aReddy, Malla  uhttps://library.ncl.res.in/content/fast-self-healing-layered-molecular-crystal-mediated-stress-induced-symmetry-breaking