Synthesis and Characterization of Triazolium Iodide Ionic Liquid Electrolyte for Dye Sensitized Solar Cells

Imidazolium iodide compounds have been utilized in the electrolytes for dye sensitized solar cells (DSSC). Most of the investigations with these compounds focus on the formulation of eutectic mixtures that promote efficient dissociation and diffusion of the iodide and triiodide species. Facile alternative synthetic approaches such as click chemistry (Huisgen 3+2 dipolar cycloaddition reaction) can be utilized to broaden the scope of electrochemically stable promising materials for novel electrolyte systems. Here, we report the first example of a triazolium functionalized cyclic siloxane that can be used as an electrolyte component in solvent-based DSSCs. The devices fabricated with this new triazolium salt in the electrolyte yielded short circuit current densities (26 mA/cm²), as well as power conversion efficiencies of 8%, these values are comparable to those obtained for imidazolium salt analogues.     

Photovoltaic Performance Enhancement in Dye-Sensitized Solar Cells with Periodic Surface Relief Structures

One-dimensional and two-dimensional periodic TiO₂ relief structures were incorporated in dye-sensitized solar cells. The periodic TiO₂ structures were fabricated using surface relief gratings photoinscribed on azobenzene functionalized polymer films as templates and TiO₂ sol-gel solution. Enhancement of power conversion of the solar cells made with the relief TiO₂ structures was achieved. This enhancement suggests that the relief TiO₂ structures can offer efficient light-trapping with the increased effective optical-path length in the solar cells.     

Synthesis and Characterization of Photoactive Amphiphilic Polymers

We have synthesized light sensitive nano micelles for their applications as drug delivery agents. Various azo compounds having different dipole moment values have been covalently attached to an amphiphilic pegylated co‐polymer and their light sensitive behavior has been studied in both aqueous and organic media with ultra violet light to understand the light dependent supramolecular organization.     

Synthesis of a self organizable curcumin derivative and investigation of its interaction with metals in 100% aqueous media

We report the synthesis of a self organizable and water dispersible bis PEGylated (bis polyethyleneglycolated) curcumin (1) using an efficient synthetic method. Compound 1 forms nanoparticles on the order of 90 nm in water. Even though it forms nanoparticles, compound 1 interacts strongly with metal ions, Al⁺³, Cu⁺², and Hg⁺². Fluorescence and absorption spectroscopic techniques were employed to investigate the metal interactions of these nanoparticles. Al⁺³ and Cu⁺² ions interact with compound 1 leading to enhancement and dramatic quenching in the fluorescence of the latter in 100% water, respectively. Addition of Hg⁺² ions to compound 1 in water produces a ratiometric change in the absorption spectra of the nanoparticles. Although PEGylated curcumin derivatives were reported in the past, there have been no reports on their self organization into nanoparticles and extensive studies on their metal interaction properties in 100% water using its fluorescence and absorption properties.     

Minimizing Carry-Over in an Online Pepsin Digestion System used for the H/D Exchange Mass Spectrometric Analysis of an IgG1 Monoclonal Antibody

Chromatographic carry-over can severely distort measurements of amide H/D exchange in proteins analyzed by LC/MS. In this work, we explored the origin of carry-over in the online digestion of an IgG1 monoclonal antibody using an immobilized pepsin column under quenched H/D exchange conditions (pH 2.5, 0?°C). From a consensus list of 169 different peptides consistently detected during digestion of this large, ~150?kDa protein, approximately 30?% of the peptic peptides exhibited carry-over. The majority of carry-over originates from the online digestion. Carry-over can be substantially decreased by washing the online digestion flow-path and pepsin column with two wash cocktails: [acetonitrile (5?%)/ isopropanol (5?%)/ acetic acid (20?%) in water] and [2?M guanidine hydrochloride in 100?mM phosphate buffer pH 2.5]. Extended use of this two-step washing procedure does not adversely affect the specificity or activity of the immobilized pepsin column. The results suggest that although the mechanism of carry-over appears to be chemical in nature, and not hydrodynamic, carry-over cannot be attributed to a single factor such as mass, abundance, pI, or hydrophobicity of the peptides.