3 research outputs found
Influence of <i>N</i>‑Alkylpyridinium Halide Based Ionic Liquids on Micellization of P123 in Aqueous Solutions: A SANS, DLS, and NMR Study
The isotropic micellar state of Pluronic
P123 in the presence and
absence of <i>N</i>-alkylpyridinium halide ionic liquids
(ILs) is investigated using SANS, DLS, and <sup>1</sup>H NMR studies.
The micellar structural parameters are obtained as a function of variation
in alkyl chain length, anions, and concentrations of ILs by fitting
the SANS scattering data with a model composed of core–shell
form factor and a hard sphere structure factor of interaction. Addition
of ILs decreases the micellar core, aggregation number, and hard sphere
radius of P123 micelles. From quantitative analysis, we determined
the amount of solvent (D<sub>2</sub>O + IL) present inside the core
and the core–shell interface along with cationic head groups.
This is further supported by monitoring interaction between ILs and
polymer micelle using <sup>1</sup>H NMR spectroscopy. The results
are discussed and explained as a function of concentration of C<sub>8</sub>PyCl, alkyl chain length, and anions of <i>N</i>-alkylpyridinium halides
Humic Acid as a Sensitizer in Highly Stable Dye Solar Cells: Energy from an Abundant Natural Polymer Soil Component
Humic acid (HA), a natural polymer
and soil component, was explored
as a photosensitizer in dye-sensitized solar cells (DSSCs). Photophysical
and electrochemical properties show that HA covers a broad visible
range of the electromagnetic spectrum and exhibits a quasi-reversible
nature in cyclic voltammetry (CV). Because of its abundant functionalities,
HA was able to bind onto the nano-titania surface and possessed good
thermal stability. HA was employed as a sensitizer in DSSCs and characterized
by various photovoltaic techniques such as <i>I</i>–<i>V</i>, incident-photo-to-current conversion efficiency (IPCE),
electrochemical impedance spectroscopy (EIS), and Tafel polarization.
The HA-based device shows a power conversion efficiency (PCE) of 1.4%
under 1 sun illumination. The device performance was enhanced when
a coadsorbent, chenodeoxycholic acid (CDCA), along with HA was used
and displayed 2.4% PCE under 0.5 sun illumination. The DSSCs employing
HA with CDCA showed excellent stability up to 1000 h. The reported
efficiency of devices with HA is better than that of devices with
all natural sensitizers reported so far
Anisotropic One-Dimensional Aqueous Polymer Gel Electrolyte for Photoelectrochemical Devices: Improvement in Hydrophobic TiO<sub>2</sub>–Dye/Electrolyte Interface
Aqueous
photoelectrochemical devices have emerged recently as promising area
because of their economic and ecological friendliness. In the present
work, we have expedited surface active amphiphilic quasi-solid aqueous
polymer gel electrolyte (PGE) with hydrophobic sensitizer SK3 in water-based
dye sensitized solar cell (DSSC). PGE was prepared from amphiphilic
block copolymer (PEO)–(PPO)–(PEO) with iodide–triiodide
couple in pure aqueous media without any organic solvent. This block
copolymer, with iodide-triiodide salt exhibits 1D-lamellar microcrystalline
phase which shows stability in the temperature range of 25–50
°C. Parallel (||<sup>al</sup>) and perpendicular (⊥<sup>ar</sup>) alignment of anisotropic lamellar microcrystalline phase
pertaining by PGE were characterized and applied in quasi-solid DSSC.
Temperature dependency of ionic conductivity, triiodide diffusion,
differential scanning calorimetry, viscosity, and 1-D lamellar anisotropic
behavior were studied. Surface active effect of PGE at the hydrophobic
dye sensitized photoanode was investigated and compared with liquid
water based electrolyte. Because of the amphiphilic nature and thermoreversible
sol–gel transition of PGE at a lower temperature (0 to −2
°C) allowing PGE to penetrate efficiently inside the hydrophobic
surface of dye–TiO<sub>2</sub> and resulted in a fused contact
between dye–TiO<sub>2</sub>/PGE interface. This aqueous PGE
successfully enhances the performance of DSSCs over liquid water based
devices by improving their <i>V</i><sub>oc</sub> and stability.
Under 0.5 sun illumination, DSSC with 1-D lamellar perpendicularly
align PGE shows an efficiency of 2.8% and stability up to 1000 h at
50 °C