Electrodeposition of Large Area, Angle-Insensitive Multilayered Structural Colors.

We demonstrate structural colors produced by a simple, inexpensive, and nontoxic electrodeposition process. Asymmetric metal-dielectric-metal (MDM) multilayered structures were achieved by sequential electrodeposition of smooth gold, thin cuprous oxide, and finally thin gold on conductive substrates, forming an effective optical cavity with angle-insensitive characteristics. Different colors of high brightness were achieved by simply tuning the thickness of the electrodeposited middle cavity layer.

Semiconductor Ultramicroelectrodes: Platforms for Studying Charge-Transfer Processes at Semiconductor/Liquid Interfaces.

Semiconductor ultramicroelectrodes (SUMEs) were prepared by photolithographic patterning of defined pinholes in dielectric coatings on semiconductor wafers. Methods are reported for interpreting their electrochemical response characteristics in the absence of illumination. Radial diffusion is reconciled with the diode equation to describe the full voltammetric response, allowing direct determination of heterogeneous charge-transfer rate constants and surface quality.

Reduction of Graphene Oxide Thin Films by Cobaltocene and Decamethylcobaltocene.

Reduced graphene oxide (RGO) films have been prepared by immersion of graphene oxide (GO) films at room temperature in nonaqueous solutions containing simple, outer-sphere metallocene reductants. Specifically, solutions of cobaltocene, cobaltocene and trifluoroacetic acid (TFA), and decamethylcobaltocene each showed activity for the rapid reduction of GO films cast on a wide variety of substrates. Each reactant increased the conductivity of the films by several orders of magnitude, with RGO films prepared with either decamethylcobaltocene or cobaltocene and TFA possessing the highest conductivities (∼10 S m).