Organic Semiconductors as Photoanodes for Solar-driven Photoelectrochemical Fuel Production

Abstract

The direct conversion of solar energy into chemical fuels, such as hydrogen, via photoelectrochemical (PEC) water splitting requires the efficient oxidation of water at a photoanode. While transition metal oxides have shown a significant success as photoanodes, their intrinsic limitations make them the bottleneck of PEC water splitting. Recently, initial research reports suggest that organic semiconductors (OSCs) could be possible alternative photoanode materials in both dye-sensitized and thin film photoelectrode configurations. Herein we review the progress to date, with a focus on the major issues faced by OSCs: stability and low photocurrent density in aqueous photoelectrochemical conditions. An outlook to the future of OSCs in photoelectrochemistry is also given.

The potential scarcity, or not, of polymeric overall water splitting photocatalysts

“…Stability is not generally an issue in sacricial hydrogen evolution with continuous hydrogen evolution for multiple days demonstrated for selected polymer materials without obvious signs of material degradation during this time. [22][23][24] However, the build-up of charges in the polymer, 51 especially holes, during overall water splitting in the presence of a sluggish water oxidation co-catalyst could result in material degradation and loss of activity. Reversely, a very active water oxidation cocatalyst, which very efficiently extracts charges from the polymer, might result in very stable polymer photocatalysts under overall water splitting conditions.…”

The potential scarcity, or not, of polymeric overall water splitting photocatalysts

“…Stability is not generally an issue in sacrificial hydrogen evolution with continuous hydrogen evolution for multiple days demonstrated for selected polymer materials without obvious signs of material degradation during this time. [22][23][24] However, the build-up of charges in the polymer, 51 especially holes, during overall water splitting in the presence of a sluggish water oxidation co-catalyst could result in material degradation and loss of activity.…”

The potential scarcity, or not, of polymeric overall water splitting photocatalysts

“…Stability is not generally an issue in sacrificial hydrogen evolution with continuous hydrogen evolution for multiple days demonstrated for selected polymer materials without obvious signs of material degradation during this time. [21][22][23] However, the build-up of charges in the polymer, 47 especially holes, during overall water splitting in the presence of a sluggish water oxidation co-catalyst could result in material degradation and loss of activity.…”