HIGHLIGHTS Low LCOE is achieved due to extreme low cost of perovskites in tandem PVs Further improving tandem module lifetime and efficiency reduces LCOE LCOE decrease rates are used to measure the research efforts

Loading ReS2 nanosheets (NSs) on planar p-type doping Si substrate has been proved that it can work well in photoelectrochemical (PEC) water splitting for hydrogen evolution reaction (HER). High PEC...

To improve PEC water splitting efficiency, Cu2O thin film electrodeposites on pyramidal Si (PSi) was innovatively introduced as an antireflective substrate combining with an Au layer. In this way, a PSi/Au/Cu2O photocathode exhibits a photocurrent enhanced 330% more than that of bare planar Si/Au/Cu2O photocathode. Compared with reversible hydrogen electrode the final fabricated photocathode with earth-abundant NiCo-LDH semiconductor cocatalyst exhibits a highly competitive photocurrent of 7.54 mA cm–2 at 0 V. It mainly results from the improved light trapping, enhanced carrier separation, and NiCo-LDH with triple enhanced effects. That means p-Cu2O and NiCo-LDH possess a type-II heterojunction to enhance photocarrier separation efficiency. Ultimately, NiCo-LDH semiconductor cocatalyst also acts as a maskant which can enhance PSi/Au/Cu2O photocathode stability. Through light trapping effect of the pyramidal Si structure and type-II heterojunction for efficient charge separation, this work provide insight into superior performance in PEC water splitting.

The heterostructuring and doping concepts have proved to obtain a novel n-InGaN/p-Cu2O nanowire (NW) photoanode by strong enhancement of the photocurrent compared to a bare InGaN NW photoanode in solar water splitting. The large photocurrent is due to the maximized photocarrier separation and hole transfer to the surface in the depletion zone of the p–n heterojunction established by the p-Cu2O layer, forming a thin, uniform shell-layer around the n-InGaN NW core by electrodeposition. For sufficiently thin Cu2O layers, the upward energy band bending in the depletion zone extends up to the surface for optimized hole transport and surface reaction. Thick Cu2O layers on top of the InGaN NWs act as common photocathodes. The functional InGaN/Cu2O heterostructure core-shell NW photoanode is chemically self-stabilized at positive applied voltage by a thin CuO surface layer. Final deposition of the earth-abundant NiOOH co-catalyst boosts the photocurrent of the InGaN/Cu2O/NiOOH complete NW photoanode into the competitive mA/cm2 range.

A one-compartment H 2 O 2 photofuel cell (PFC) with a photoanode based on InGaN nanowires (NWs) is introduced for the first time. The electrocatalytic and photoelectrocatalytic properties of the InGaN NWs are studied in detail by cyclic voltammetry, current versus time measurements, photovoltage measurements, and electrochemical impedance spectroscopy. In parallel, IrO x (OH) y as the co-catalyst on the InGaN NWs is evaluated to boost the catalytic activity in the dark and light. For the PFC, Ag is the best as the cathode among Ag, Pt, and glassy carbon. The PFC operates in the dark as a conventional fuel cell (FC) and under illumination with 25% increased electrical power generation at room temperature. Such dual operation is unique, combining FC and PFC technologies for the most flexible use.

A novel self‐powered InGaN/SiNx/Si uniband diode photodetector (PD) is introduced. The full band structure is first constructed from the transition of direct tunneling to Fowler‐Nordheim tunneling of holes through the ultrathin SiNx interlayer at forward bias in the dark. Basis is the alignment of the n‐InGaN conduction band with the p‐Si valence band at zero bias. Under illumination, the photocurrent, responsivity, and bandwidth for the self‐powered PD at zero bias indicate two distinct operation modes (i) for longer and (ii) for shorter wavelengths of incident light. The two modes involve (i) absorption in Si and electron tunneling through the SiNx interlayer and (ii) absorption in InGaN and hole transport across the SiNx interlayer. The noise is considerably larger in operation mode (i) than in operation mode (ii). This is attributed to the presence or absence of energy barriers for electron and hole transport in PD operation. Hence, noise is introduced as an independent parameter to discriminate between longer and shorter wavelength regions in dual‐wavelength photodetection.

InN/InGaN quantum dots (QDs) are introduced as an efficient photoanode for a novel abiotic one-compartment photofuel cell (PFC) with a Pt cathode and glucose as a biofuel. Due to the high catalytic activity and selectivity of the InN/InGaN QDs toward oxidation reactions, the PFC operates without a membrane under physiologically mild conditions at medium to low glucose concentrations with a noble-metal-free photoanode. A relatively high short-circuit photocurrent density of 0.56 mA/cm 2 and a peak output power density of 0.22 mW/cm 2 are achieved under 1 sun illumination for a 0.1 M glucose concentration with optimized InN/InGaN QDs of the right size. The super-linear dependence of the short-circuit photocurrent density and the output power density as a function of the logarithmic glucose concentration makes the PFC well suited for sensing, covering the 4–6 mM range of glucose concentration in blood under normal conditions with good selectivity. No degradation of the PFC operation over time is observed.

Doping nitrogen into titanium dioxide (N–TiO2) is vital to extend its photocatalytic activity to the visible-light range. However, this often leads to a significant decrease in film transparency, which hinders its usage in environmental applications. In this study, we report the deposition of N–TiO2 films with a visible-light activity and improved transparency. Using pulsed magnetron sputtering, we achieve a high concentration (∼7.5%) of nitrogen incorporation into anatase TiO2 films. This results in a much-reduced band gap (∼1.92 eV) and remarkable photocatalytic performance in the visible-light range. More importantly, the transparency of the films does not decrease significantly even at this high doping concentration, in contrast to the samples prepared using the conventional direct current (DC) sputtering process. First-principles calculations indicate that the improved incorporation of nitrogen at the substitutional lattice sites is responsible for the reduced band gap and improved transparency. This work demonstrates a viable method to achieve transparent N–TiO2 films with a visible-light activity, which could be useful for various environmental applications such as self-cleaning glass.