To explore the origin of the enhanced photocatalytic activity of Mo-doped monoclinic BiVO4, variations of the structures and the electronic properties, as well as the adsorption behavior of water on the (010) surface, introduced by the Mo dopant have been investigated by means of density functional theory computations. For the bulk phase, Mo atoms prefer to substitute the V atoms, which can effectively accelerate the separation of carriers. For the (010) surface, Mo atoms prefer to substitute the Bi atoms at the outermost layer. Mo doping on the surface can result in surface oxygen quasi-vacancies and enhance the exposure of surface Bi atoms, which is confirmed to improve the adsorption of water molecules. Our results demonstrate that the enhanced photocatalytic activity of Mo-doped monoclinic BiVO4 is derived from the facilitated separation of photoinduced carriers and introduced surface oxygen quasi-vacancies.

Zn(2)GeO(4) nanorods were prepared by a surfactant-assisted hydrothermal method and used as photocatalysts for the decomposition of organic pollutants in water. The physicochemical properties of the Zn(2)GeO(4) photocatalysts were characterized by several techniques, and their photocatalytic activity was evaluated by the decomposition of methyl orange, salicylic acid, and 4-chlorophenol in aqueous solution. The results revealed that the Zn(2)GeO(4) nanorods have a much higher photocatalytic activity for decomposing organic pollutants in aqueous solution than both Zn(2)GeO(4) prepared by a conventional solid-state reaction and widely used TiO(2) (Degussa P25). There is no obvious deactivation of Zn(2)GeO(4) nanorods in the photocatalytic reactions. The intermediates of the photocatalytic reactions were monitored by LC-MS, and possible photocatalytic reaction pathways as to how Zn(2)GeO(4) nanorods degrade organic dyes were proposed.

A highly transparent passivating contact (TPC) as front contact for crystalline silicon (c-Si) solar cells could in principle combine high conductivity, excellent surface passivation and high optical transparency. However, the simultaneous optimization of these features remains challenging. Here, we present a TPC consisting of a silicon-oxide tunnel layer followed by two layers of hydrogenated nanocrystalline silicon carbide (nc-SiC:H(n)) deposited at different temperatures and a sputtered indium tin oxide (ITO) layer (c-Si(n)/SiO2/nc-SiC:H(n)/ITO). While the wide band gap of nc-SiC:H(n) ensures high optical transparency, the double layer design enables good passivation and high conductivity translating into an improved short-circuit current density (40.87 mA cm−2), fill factor (80.9%) and efficiency of 23.99 ± 0.29% (certified). Additionally, this contact avoids the need for additional hydrogenation or high-temperature postdeposition annealing steps. We investigate the passivation mechanism and working principle of the TPC and provide a loss analysis based on numerical simulations outlining pathways towards conversion efficiencies of 26%.

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