A BiVO4 with a preferred [001] orientation and exposed {001} facets were grown epitaxially on FTO via a laser ablation, achieving the state-of-the-art photoelectrochemical performance for solar water-oxidation.

In this study, an aluminum-doped zinc oxide (AZO) layer was used as a transparent conducting oxide (TCO) layer in ZnO nanowire (NW)-based dye-sensitized solar cells (DSSCs). The well aligned, single crystalline ZnO NW arrays that were grown on the AZO films exhibited a better DSSC performance (an increased photocurrent density and fill factor) than those grown on the fluorine doped tin oxide (FTO) films. The I−V characteristics and electrochemical impedance spectroscopy measurements for the ZnO NW arrays on the AZO and FTO films clearly showed that the superior DSSC performance was caused by the facilitated charge injection from the ZnO NW to AZO, resulting from the formation of an ohmic contact. This study demonstrates that the AZO films are more favorable for highly efficient ZnO NW-based photoenergy conversion devices.

Vertical growth of carbon nanotubes using thermal chemical vapor deposition (CVD) is demonstrated on bulk copper substrates by first sputtering a thin Ni film on the surface of copper. Vertical growth of carbon nanotubes occurred when the nickel film thickness was 20 nm and the carbon nanotubes were grown using a xylene source and additional ferrocene catalyst during CVD. These results show the effectiveness of this method in directly integrating carbon nanotubes with highly conductive substrates for applications where a conductive carbon nanotube network is desirable.

We demonstrate high-performance perovskite solar cells with excellent electron transport properties using a one-dimensional (1D) electron transport layer (ETL). The 1D array-based ETL is comprised of 1D SnO2 nanowires (NWs) array grown on a F:SnO2 transparent conducting oxide substrate and rutile TiO2 nanoshells epitaxially grown on the surface of the 1D SnO2 NWs. The optimized devices show more than 95% internal quantum yield at 750 nm, and a power conversion efficiency (PCE) of 14.2%. The high quantum yield is attributed to dramatically enhanced electron transport in the epitaxial TiO2 layer, compared to that in conventional nanoparticle-based mesoporous TiO2 (mp-TiO2) layers. In addition, the open space in the 1D array-based ETL increases the prevalence of uniform TiO2/perovskite junctions, leading to reproducible device performance with a high fill factor. This work offers a method to achieve reproducible, high-efficiency perovskite solar cells with high-speed electron transport.

For photoelectrochemical (PEC) hydrogen production, low charge transport efficiency of a photoelectrode is one of the key factors that largely limit PEC performance enhancement. Here, we report a tin-doped indium oxide (In2O3:Sn, ITO) nanowire array (NWs) based CdSe/CdS/TiO2 multishelled heterojunction photoelectrode. This multishelled one-dimensional (1D) heterojunction photoelectrode shows superior charge transport efficiency due to the negligible carrier recombination in ITO NWs, leading to a greatly improved photocurrent density (∼16.2 mA/cm2 at 1.0 V vs RHE). The ITO NWs with an average thickness of ∼12 μm are first grown on commercial ITO/glass substrate by a vapor–liquid–solid method. Subsequently, the TiO2 and CdSe/CdS shell layers are deposited by an atomic layer deposition (ALD) and a chemical bath deposition method, respectively. The resultant CdSe/CdS/TiO2/ITO NWs photoelectrode, compared to a planar structure with the same configuration, shows improved light absorption and much faster charge transport properties. More importantly, even though the CdSe/CdS/TiO2/ITO NWs photoelectrode has lower CdSe/CdS loading (i.e., due to its lower surface area) than the mesoporous TiO2 nanoparticle based photoelectrode, it shows 2.4 times higher saturation photocurrent density, which is attributed to the superior charge transport and better light absorption by the 1D ITO NWs.