The photocathode exhibits 100% Faradaic efficiency and a photocurrent density of 3 mA cm2 at 0.0 V RHE.

Anodically grown WO3 photoelectrodes prepared in an N-methylformamide (NMF) electrolyte have been investigated with the aim of exploring the effects induced by anodization time and water concentration in the electrochemical bath on the properties of the resulting photoanodes. An n-type WO3 semiconductor is one of the most promising photoanodes for hydrogen production from water splitting and the electrochemical anodization of tungsten allows very good photoelectrodes, which are characterized by a low charge-transfer resistance and an increased spectral response in the visible region, to be obtained. These photoanodes were investigated by a combination of steady state and transient photoelectrochemical techniques and a correlation between photocurrent produced, morphology, and charge transport has been evaluated

Precise, reliable, and remote measurement of dissolved oxygen in aqueous media is of great importance for many industrial, environmental, and biological applications. In particular, photoelectrochemical sensors working in differential mode have recently demonstrated promising properties, in terms of stability, sensitivity, and application potential. Here, a new approach is presented, combining visible light sensitivity, effi cient photocurrent generation, and solution-processed fabrication methods of conjugated polymers, with charge carriers selectivity, energetic alignment favorable to effi cient interfacial charge transfer and high surface area achievable by using metal oxide nanostructures. Extensive characterization and optimization of the hybrid organic/inorganic system are carried out, leading to the realization of an oxygen sensor device, based on nanostructured palladium oxide/poly[(9,9-dioctylfl uorenyl-2,7-diyl)-alt -5,5-(4′,7′-di-2thienyl-2′,1′,3′-benzothiadiazole]/[6,6]phenyl-C61-butyric acid methyl ester (PdO/APFO-3:PCBM) as materials of choice. State-of-the-art sensitivity, amounting at −5.87 µA cm −2 ppm −1 , low background signal, in the order of −4.85 µA cm −2 , good electrochemical stability for more than 2 h of continuous functioning and high reproducibility of the signal over the pH 1 to 10 range, are reported, making the hybrid device suitable for several practical uses. The results fully validate the mixed organic/inorganic approach for photoelectrochemical applications, and pave the way for its further exploitation in fi elds like waste water treatment, environmental monitoring, and water splitting.

No abstract

The replacement of common fullerene derivatives with neat-C70 could be an effective approach to restrain the costs of organic photovoltaics and increase their sustainability. In this study, bulk-heterojunction solar cells made of neat-C70 and low energy-gap conjugated polymers, PTB7 and PCDTBT, are thoroughly investigated and compared. Upon replacing PC70BM with C70, the mobility of positive carriers in the donor phase is roughly reduced by 1 order of magnitude, while that of electrons is only slightly modified. It is shown that the main loss mechanism of the investigated neat-C70 solar cells is a low mobility-lifetime product. Nevertheless, PCDTBT:C70 devices undergo a limited loss of 7.5%, compared to the reference PCDTBT:PC70BM cells, reaching a record efficiency (4.44%) for polymer solar cells with unfunctionalized fullerenes. The moderate efficiency loss of PCDTBT:C70 devices, due to an unexpected excellent miscibility of PCDTBT:C70 blends, demonstrates that efficient solar cells made of neat-fullerene are possible. The efficient dispersion of C70 in the PCDTBT matrix is attributed to an interaction between fullerene and the carbazole unit of the polymer.