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Very efficient electrogenerated chemiluminescence (ECL) phenomena were realized by deliberately tuning electron-transfer reactions from electrochemically generated electron donor to metal complex radical cations. By controlling the relative positions of HOMO and LUMO levels (oxidation potential and reduction potential) of Ir(III) complexes, we could obtain 77 times higher ECL from iridium(III) complexes in the presence of TPA than that of the Ru(bpy)32+/TPA system. This high ECL efficiency of new Ir(III) complexes can be used in many interesting applications such as sensors and luminescent devices.

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The enantioselective recognition of 3,4-dihydroxyphenylalanine using penicillamine-modified gold nanoparticles has been investigated. Smaller gold nanoparticles with one enantiomeric ligand facilitate the redox reaction of only one enantiomer of 3,4-dihydroxyphenylalanine, with cross inversion for the gold nanoparticles with the other enantiomeric ligand.

Sulfonic acid-functionalized graphene (S-graphene) is employed as a promising inorganic filler as well as a solid acid proton conducting medium to realize a composite membrane with Nafion for polymer electrolyte fuel cell (PEFC) applications under reduced relative humidity (RH). The functionalization of graphene is performed by sulfonic acid-containing aryl radicals to increase the number of sulfonate groups per unit volume of a domain. A Nafion−S-graphene composite membrane is obtained by embedding S-graphene in Nafion, which provides high absorption of water and fast proton-transport across the electrolyte membrane under low RH values. The proton conductivity of the Nafion−S-graphene (1%) composite membrane at 20% RH is 17 mS cm −1 , which is five times higher than that of a pristine recast Nafion membrane. PEFCs incorporating the Nafion−S-graphene composite membrane deliver a peak power density of 300 mW cm −2 at a load current density of 760 mA cm −2 while operating at optimum temperature of 70 °C under 20% RH and ambient pressure. By contrast, operating under identical conditions, a peak power density of 220 mW cm −2 is achieved with the pristine recast Nafion membrane. The Nafion−S-graphene composite membrane could be used to address many critical problems associated with commercial Nafion membranes in fuel cell applications.

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