RNA-mediated fluorescent PbS nanoparticles have been synthesized in the quantum-confined region of a face-centered cubic phase. The binding of RNA to the surface of PbS nanoparticles has been exploited to tailor its size and to improve the stability and electronic properties. These particles display excitonic features and a relatively strong narrow emission band (fwhm 70 nm) at 675 nm with a broad excitation range extending from 330 to 620 nm. The manipulation of experimental conditions could control the relaxation dynamics of charge carriers in the illuminated particles. The multifunctionality of the RNA structure contributes to the observed electronic properties in a cooperative manner. Such biopolymeric nanostructures may find tremendous applications in the fabrication of solar cells, fluorescence imaging, and detection devices.
The presence of excess Pb(2+) in the building block consisting of RNA-mediated PbSe QDs induces polarization in PbSe resulting in an increased red fluorescence associated with enhanced charge separation and supramolecular interactions between different building blocks to produce nanotubular morphology in self-assembly.
The present research on an aqueous
electrolyte(s)-based supercapacitor,
considered to be the next-generation storage device, is mainly focused
on to achieve a wide potential window with high energy density. However,
the water decomposition in the aqueous electrolyte has posed a major
challenge to be tackled to perceive its future prospect. In this context,
the present work has undertaken a systematic investigation to analyze
the role of ions in the recently explored “water-in-salt”
electrolyte(s) attaining the high cell voltage for the symmetric supercapacitor
cell (SSC), constructed using N-doped reduced graphene oxide as the
electrode material. The nature of electrolytic ions toward affecting
the H-bonding network of the water structure and thereby influencing
the cell voltage stability has been investigated by employing different
electrolytes: 7 m CH3COONa; 2, 7, 12, and 17 m NaClO4; 2, 5, 7, and 11 m NaNO3; and 7, 17, 22, and 27
m CH3COOK. It exhibited the highest cell voltage of 2.7
V in 17 m NaClO4 with an energy density of 140 W h/kg at
640 W/kg, whereas for 11 m NaNO3, a cell voltage of 2.3
V is observed with an energy density of 72 W h/kg at 545 W/kg. In
contrast, for 7 m CH3COONa and 27 m CH3COOK,
cell voltages of 1.9 and 2.0 V have been obtained with energy densities
of 40 W h/kg at 474 W/kg and 41 W h/kg at 500 W/kg, respectively.
Among these electrolytes, the ClO4
– anion
and NO3
– anion are found to be the water
structure breakers (chaotrope), but the ClO4
– anion exhibited much better chaotropicity as compared to the NO3
– anion. In contrast, the CH3COO– anion is found to act as a water structure
maker (kosmotrope) anion. To the best of our knowledge, this is among
the highest cell voltages (2.7 V) obtained in the aqueous electrolyte-based
symmetric supercapacitor with superb energy density and power density.
Its potential for energy storage application has been illustrated
by lighting 54 white light-emitting diodes (>3 V) for more than
6
min upon charging a single SSC for about 15 s.
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