Corner-Sharing Tetrahedrally Coordinated W-V Dual Active Sites on Cu2 V2 O7 for Photoelectrochemical Water Oxidation.

The sluggish four-electron oxygen evolving reaction is one of the key limitations of photoelectrochemical water decomposition. Optimizing the binding of active sites to oxygen in water and promoting the conversion of *O to *OOH are the key to enhancing oxygen evolution reaction. In this work, W-doped Cu2 V2 O7 (CVO) constructs corner-sharing tetrahedrally coordinated W-V dual active sites to induce the generation of electron deficiency active centers, promote the adsorption of ─OH, and accelerate the transformation of *O to *OOH for water splitting. The photocurrent obtained by the W-modified CVO photoanode is 0.97 mA cm-2 at 1.23 V versus RHE, which is much superior to that of the reported CVO. Experimental and theoretical results show that the excellent catalytic performance may be attributed to the formation of synergistic dual active sites between W and V atoms, and the introduction of W ions reduces the charge migration distance and prolongs the lifetime of photogenerated carriers. Meanwhile, the electronic structure in the center of the d-band is modulated, which leads to the redistribution of the electron density in CVO and lowers the energy barrier for the conversion of the rate-limiting step *O to *OOH.

Metal Oxide Based Photoelectrodes in Photoelectrocatalysis: Advances and Challenges.

Metal oxide materials show promise for application in photoelectrocatalytic conversion due to their inherent advantages involving positive reactive surface, improved light absorption capability, efficient charge separation yield, and fast charge transport channels. The unique electrical and optical properties of metal oxide based photoelectrodes have a great effect on their performance in solar cells, photoelectrocatalysis, and photocatalysis. It has been reported that the presence of defects on grain boundaries, oxygen vacancy, doping strategy, and heterojunction play a vital role in both the efficiency and durability of their photoelectric application. However, the intrinsic mechanisms at the atomic level remained unclear, which require more in-depth understanding in terms of theoretical analysis. In this Review, we emphatically introduce the recent advances and current challenges of metal oxide-based photoelectrodes for photoelectrocatalytic application, beneath the structure-activity relationship of metal oxide catalysts. Then, we give a summary of the state-of-the-art research in the preparation and application for the metal oxide based composite materials. Finally, we discuss key aspects, which should be addressed for design and construction.

Interfacial Linkage and Carbon Encapsulation Enable Full Solution-Printed Perovskite Photovoltaics with Prolonged Lifespan.

Simplified perovskite solar cells (PSCs) were fabricated with the perovskite layer sandwiched and encapsulated between carbon-based electron transport layer (ETL) and counter electrode (CE) by a fully blade-coated process. A self-assembled monolayer of amphiphilic silane (AS) molecules on transparent conducting oxide (TCO) substrate appeals to the fullerene ETL deposition and preserves its integrity against the solvent damage. The AS serves as a "molecular glue" to strengthen the adhesion toughness at the TCO/ETL interface via robust chemical interaction and bonding, facilitating the interfacial charge extraction, increasing PCEs by 77 % and reducing hysteresis. A PCE of 18.64 % was achieved for the fully printed devices, one of the highest reported for carbon-based PSCs. AS-assisted interfacial linkage and carbon-material-assisted self-encapsulation enhance the stability of the PSCs, which did not experience performance degradation when stored at ambient conditions for over 3000 h.

UBE2D3 is a positive prognostic factor and is negatively correlated with hTERT expression in esophageal cancer.

Human telomerase reverse transcriptase (hTERT) is a critical factor in unlimited cell proliferation and immortalization, with numerous studies demonstrating that high expression of hTERT is a poor prognostic factor in various types of cancer. Ubiquitin-conjugating enzyme E2D 3 (UBE2D3) is a member of the E2 family, and participates in the ubiquitin proteasome pathway to regulate basic cellular activities, such as cell cycle control, the DNA damage response, apoptosis, and tumorigenesis. Our previous study initially determined that downregulation of UBE2D3 expression increases hTERT expression and cell proliferation, however, the association between the expression of these two proteins and their functions in cancer tissues remains unknown. Therefore, the protein expression levels of hTERT and UBE2D3 were evaluated in 150 esophageal cancer and 30 adjacent healthy tissue samples by performing immunohistochemical analysis. Concurrently, the clinicopathological data of the enrolled patients were obtained to allow correlation analysis. It was identified that the expression of hTERT in the esophageal cancer tissues was significantly higher compared with that of the adjacent tissues (P=0.015), however, the expression of UBE2D3 was significantly lower in esophageal cancer tissues than the adjacent tissues (P=0.001). Additionally, the study demonstrated that hTERT was significantly upregulated in poorly-differentiated, advanced tumor-node-metastasis (TNM) stage cancer tissues (P<0.05 for all), however, UBE2D3 expression was downregulated in poorly-differentiated, lymph node invaded cancer tissues and recurrent cases. It was also identified that traditional factors, including tumor location, T stage, lymph node status, TNM stage, and molecular factors of hTERT and UBE2D3, were significantly associated with overall survival time (P<0.05 for all). Furthermore, UBE2D3, lymph node status and tumor location were independent prognostic factors for esophageal cancer in multivariate analysis. Most notably, hTERT and UBE2D3 expression were negatively correlated with each other. In conclusion, the findings of the present study indicated that hTERT and UBE2D3 proteins appear to be involved in the development of esophageal cancer, that UBE2D3 may a positive prognostic factor for esophageal cancer, and that UBE2D3 and hTERT expression levels are inversely correlated.

Hydrothermal fabrication of hierarchically anatase TiO2 nanowire arrays on FTO glass for dye-sensitized solar cells.

Hierarchical anatase TiO(2) nano-architecture arrays consisting of long TiO(2) nanowire trunk and numerous short TiO(2) nanorod branches on transparent conductive fluorine-doped tin oxide glass are successfully synthesized for the first time through a facile one-step hydrothermal route without any surfactant and template. Dye-sensitized solar cells based on the hierarchical anatase TiO(2) nano-architecture array photoelectrode of 18 µm in length shows a power conversion efficiency of 7.34% because of its higher specific surface area for adsorbing more dye molecules and superior light scattering capacity for boosting the light-harvesting efficiency. The present photovoltaic performance is the highest value for the reported TiO(2) nanowires array photoelectrode.

Hierarchical TiO2 flowers built from TiO2 nanotubes for efficient Pt-free based flexible dye-sensitized solar cells.

A novel hierarchical TiO(2) flower consisting of anatase TiO(2) nanotubes on a Ti foil substrate has been prepared via a mild hydrothermal reaction of TiO(2) nanoparticles/Ti foil. The photovoltaic performance of DSSC based on hierarchical TiO(2) flowers/Ti (7.2%) is much higher than that of TiO(2) nanoparticle/Ti (6.63%) because of its superior light scattering ability and fast electron transport. Moreover, full flexible DSSC based on the novel hierarchical TiO(2) flowers/Ti foil photoelectrode and electrodeposited poly(3,4-ethylenedioxythiophene) (PEDOT) on indium tin oxide-coated poly(ethylene terephthalate) (ITO-PET) counter electrode shows a significant power conversion efficiency of 6.26%, accompanying a short-circuit current density of 11.96 mA cm(-2), an open-circuit voltage of 761 mV and a fill factor of 0.69.

Highly catalytic carbon nanotube/Pt nanohybrid-based transparent counter electrode for efficient dye-sensitized solar cells.

Low-cost transparent counter electrodes (CEs) for efficient dye-sensitized solar cells (DSSCs) are prepared by using nanohybrids of carbon nanotube (CNT)-supported platinum nanoparticles as highly active catalysts. The nanohybrids, synthesized by an ionic-liquid-assisted sonochemical method, are directly deposited on either rigid glass or flexible plastic substrates by a facile electrospray method for operation as CEs. Their electrochemical performances are examined by cyclic voltammetry, current density-voltage characteristics, and electrochemical impedance spectroscopy (EIS) measurements. The CNT/Pt hybrid films exhibit high electrocatalytic activity for I(-)/I(3)(-) with a weak dependence on film thickness. A transparent CNT/Pt hybrid CE film about 100 nm thick with a transparency of about 70% (at 550 nm) can result in a high power conversion efficiency (η) of over 8.5%, which is comparable to that of pyrolysis platinum-based DSSCs, but lower cost. Furthermore, DSSC based on flexible CNT/Pt hybrid CE using indium-doped tin oxide-coated polyethylene terephthalate as the substrate also exhibits η=8.43% with J(sc)=16.85 mA cm(-2), V(oc)=780 mV, and FF=0.64, and this shows great potential in developing highly efficient flexible DSSCs.

Hydrothermal fabrication of quasi-one-dimensional single-crystalline anatase TiO2 nanostructures on FTO glass and their applications in dye-sensitized solar cells.

One-dimensional and quasi-one-dimensional semiconductor nanostructures are desirable for dye-sensitized solar cells (DSSCs), since they can provide direct pathways for the rapid collection of photogenerated electrons, which could improve the photovoltaic performance of the device. Quasi-1D single-crystalline anatase TiO(2) nanostructures have been successfully prepared on transparent, conductive fluorine-doped tin oxide (FTO) glass with a growth direction of [101] through a facile hydrothermal approach. The influences of the initial titanium n-butoxide (TBT) concentration, hydrothermal reaction temperature, and time on the length of quasi-1D anatase TiO(2) nanostructures and on the photovoltaic performance of DSSCs have been investigated in detail. A power conversion efficiency of 5.81% has been obtained based on the prepared TiO(2) nanostructure photoelectrode 6.7 µm thick and commercial N719 dye, with a short-circuit current density of 13.3 mA cm(-2) , an open-circuit voltage of 810 mV, and a fill factor of 0.54.

Sonochemical preparation of hierarchical ZnO hollow spheres for efficient dye-sensitized solar cells.

Hierarchical ZnO hollow spheres (400-500 nm in diameter) consisting of ZnO nanoparticles with a diameter of approximately 15 nm have been successfully prepared by a facile and rapid sonochemical process. The formation of hierarchical ZnO hollow spheres is attributed to the oriented attachment and subsequent Ostwald ripening process according to time-dependent experiments. The as-prepared ZnO hollow spheres are used as a photoanode in dye-sensitized solar cells and exhibit a highly efficient power conversion efficiency of 4.33%, with a short-circuit current density of 9.56 mA cm(-2), an open-circuit voltage of 730 mV, and a fill factor of 0.62 under AM 1.5 G one sun (100 mW cm(-2)) illumination. Moreover, the photovoltaic performance (4.33%) using the hierarchical ZnO hollow spheres is 38.8% better than that of a ZnO nanoparticle photoelectrode (3.12%), which is mainly attributed to the efficient light scattering for the former.

Facile fabrication of hierarchical SnO(2) microspheres film on transparent FTO glass.

Hierarchical SnO(2) microspheres consisting of nanosheets on the fluorine-doped tin oxide (FTO) glass substrates are successfully prepared via a facile hydrothermal synthesis process. The as-prepared novel microsphere films were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy. Moreover, SnO(2) nanoparticles with 30-80 nm in size covered on the surface of nanosheets/microspheres were also obtained by optimizing the hydrothermal reaction temperature, time, or volume ratio of acetylacetone/H(2)O. The detailed investigations disclose the experimental parameters, such as acetylacetone, NH(4)F, and seed layer play important roles in the morphology of hierarchical SnO(2) microspheres on the FTO glass. The formation process of SnO(2) microspheres is also proposed based on the observations of time dependent samples.