Enrique A. Dalchiele

A transparent solid-state ion gel for supercapacitor device applications

AbstractA feasibility study of the synthesis of gel polymer electrolytes based in methyl methacrylate (MMA) and 1-vinyl-2-pyrrolidone (VP) using [HEMIm][BF4] as common ionic liquid has been done. A novel PVP/[HEMIm][BF4] solid-state and self-standing ion gel electrolyte has been successfully prepared. The thermal degradation of PVP/[HEMIm][BF4] ion gel occurs in two steps with the first one at above 200xa0°C and the main one over 390xa0°C. This solid-state ion gel is transparent, showing an optical transmittance with a maximum value of 90% in the visible wavelength region from 370 to 770xa0nm. The synthesized PVP/[HEMIm][BF4] solid-state ion gel exhibits an electrochemical stability window of ca. 5.0xa0V and an acceptable ionic conductivity of σxa0=xa05.7 10−3xa0Sxa0cm−1 at room temperature. A symmetrical pseudocapacitive supercapacitor has been assembled and characterized using this PVP/[HEMIm][BF4] solid-state ion gel—glass/ITO/PEDOT/PVP/[HEMIm][BF4]/PEDOT/ITO/glass. It is found that the supercapacitor shows a typical areal specific capacitance of 3.1xa0mFxa0cm−2, a maximum energy density of 2.5xa0μWhxa0cm−2, and an areal specific power density of ca. 1xa0mWxa0cm−2.n Graphical abstractSqueme and cyclic voltammogram curves of the tested supercapacitor device

Fullerenes Covalently Anchored On Si(100): An Experimental Study

Various [60]fullerene derivatives were covalently anchored via a Si‐C bond to hydrogen‐terminated Si(100) following wet‐chemistry recipes. The applied reactions require a two‐step approach consisting of a pre‐modification of the Si(100) surface with an organic monolayer bearing a terminal functionality that undergoes a bond‐forming reaction with a [60]fullerene synthon. The resulting Si‐C bound hybrids were characterized by a combination of XPS, AFM, contact angle, and electrochemical analysis. The hybrid surfaces containing [60rsqb;fullerene‐ferrocene fragments are exceptionally robust towards repeated reduction‐oxidation cycles. Moreover, several surface‐confined redox couples were observed in CH3CN solution. The surface coverage was measured to be ca. 2.5×10−11u2009molu2009cm−2.