High‐temperature polymer electrolyte membrane fuel cells are promising alternatives to low temperature fuel cells, owing to their higher operating temperatures, which allow for easier water management and enhanced catalytic activity. However, their performance suffers from low oxygen solubility in the electrolyte and phosphoric acid poisoning of catalytically active Pt sites. In this work, we developed new organic additives that provide π‐π stacking of the commercially applied carbon support materials as well as variable substitutable functionalities to interact with the Pt nanoparticles. Different electrochemical methods, such as cyclic voltammetry and linear sweep voltammetry, were performed to test the effect of these organic additives on the onset potential, limiting current, and the number of transferred electrons. It is observed that the limiting currents increase for the additive‐modified Pt/C samples, whereas the onset potential for significant oxygen reduction reaction activity remains unchanged. We conclude that enhanced oxygen solubility at the electrode/electrolyte interface is the reason for the observed behavior.

The absorption and emission properties of organic dyes are generally tuned by altering the substitution pattern. However, tuning the fluorescence lifetimes over a range of several 10 ns while barely affecting the spectral features and maintaining a moderate fluorescence quantum yield is challenging. Such properties are required for lifetime multiplexing and barcoding applications. Here, we show how this can be achieved for the class of fluoranthene dyes, which have substitution-dependent lifetimes between 6 and 33 ns for single wavelength excitation and emission. We explore the substitution-dependent emissive properties in the crystalline solid state that would prevent applications. Furthermore, by analyzing dye mixtures and embedding the dyes in carboxyfunctionalized 8 μm-sized polystyrene particles, the unprecedented potential of these dyes as labels and encoding fluorophores for time-resolved fluorescence detection techniques is demonstrated.

The Cover Feature illustrates planar additives with a large π network and functional groups for self‐assembly via π–π‐stacking on the carbon support in high‐temperature polymer electrolyte membrane fuel cells. The polyaromatic hydrocarbon fluoranthene consists of a naphthalene unit, which is fused to a benzene unit through a five membered ring. The fluoranthene framework can interact via π–π‐interaction with the carbon, whereas the functional groups can interact with the Pt particles anchored on the support. More information can be found in the Article by Ö. Delikaya et al. on page 3892 in Issue 15, 2019 (DOI: 10.1002/celc.201900251).