Theoretical analysis connecting photovoltaics and colorimetry reveals the ultimate efficiency limits of colorful single-band-gap solar cells and modules.

Bench top stable transition metal (M = Co, Ni, Cu) complexes with a non-innocent ortho-aminophenol derivative were synthesized by the reaction of metal(II)acetates with a ligand precursor in 2:1 ratio.The solid-state structures reveal the formation of neutral molecular complexes with square planar coordination geometries. The Co(II) and Cu(II) complexes are paramagnetic, whereas the Ni complex is a diamagnetic square planar low-spin Ni(II) complex. All complexes, and Ni(II) complex in particular, show strong absorption in the near-IR region.

Single-layer ceramic fuel cells consisting of Li0.15Ni0.45Zn0.4O2, Gd0.2Ce0.8O2 and a eutectic mixture of Li2CO3, Na2CO3 and K2CO3, were fabricated through extrusion-based 3D printing. The sintering temperature of the printed cells was varied from 700 °C to 1000 °C to identify the optimal thermal treatment to maximize the cell performance. It was found that the 3D printed single-layer cell sintered at 900 °C produced the highest power density (230 mW/cm2) at 550 °C, which is quite close to the performance (240 mW/cm2) of the single-layer cell fabricated through a conventional pressing method. The best printed cell still had high ohmic (0.46 Ω·cm2) and polarization losses (0.32 Ω·cm2) based on EIS measurements conducted in an open-circuit condition. The XRD spectra showed the characteristic peaks of the crystalline structures in the composite material. HR-TEM, SEM and EDS measurements revealed the morphological information of the composite materials and the distribution of the elements, respectively. The BET surface area of the single-layer cells was found to decrease from 2.93 m2/g to 0.18 m2/g as the sintering temperature increased from 700 °C to 1000 °C. The printed cell sintered at 900 °C had a BET surface area of 0.34 m2/g. The fabrication of single-layer ceramic cells through up-scalable 3D technology could facilitate the scaling up and commercialization of this promising fuel cell technology.

This study investigates the contribution of different CH4 sources to the seasonal cycle of δ13C during 2000–2012 by using the TM5 atmospheric transport model, including spatially varying information on isotopic signatures. The TM5 model is able to produce the background seasonality of δ13C, but the discrepancies compared to the observations arise from incomplete representation of the emissions and their source-specific signatures. Seasonal cycles of δ13C are found to be an inverse of CH4 cycles in general, but the anti-correlations between CH4 and δ13C are imperfect and experience a large variation (p=−0.35 to −0.91) north of 30° S. We found that wetland emissions are an important driver in the δ13C seasonal cycle in the Northern Hemisphere and Tropics, and in the Southern Hemisphere Tropics, emissions from fires contribute to the enrichment of δ13C in July–October. The comparisons to the observations from 18 stations globally showed that the seasonal cycle of EFMM emissions in the EDGAR v5.0 inventory is more realistic than in v4.3.2. At northern stations (north of 55° N), modeled δ13C amplitudes are generally smaller by 12–68%, mainly because the model could not reproduce the strong depletion in autumn. This indicates that the CH4 emission magnitude and seasonal cycle of wetlands may need to be revised. In addition, results from stations in northern latitudes (19–40° N) indicate that the proportion of biogenic to fossil-based emissions may need to be revised, such that a larger portion of fossil-based emissions is needed during summer.

Abstract. This study investigates the contribution of different CH4 sources to the seasonal cycle of 𝛿13C during years 2000–2012 using the TM5 atmospheric transport model. The seasonal cycles of anthropogenic emissions from two versions of the EDGAR inventories, v4.3.2 and v5.0 are examined. Those includes emissions from Enteric Fermentation and Manure Management (EFMM), rice cultivation and residential sources. Those from wetlands obtained from LPX-Bern v1.4 are also examined in addition to other sources such as fires and ocean sources. We use spatially varying isotopic source signatures for EFMM, coal, oil and gas, wetlands, fires and geological emission and for other sources a global uniform value. We analysed the results as zonal means for 30° latitudinal bands. Seasonal cycles of 𝛿13C are found to be an inverse of CH4 cycles in general, with a peak-to-peak amplitude of 0.07–0.26 ‰. However, due to emissions, the phase ellipses do not form straight lines, and the anti-correlations between CH4 and 𝛿13C are weaker (−0.35 to −0.91) in north of 30° S. We found that wetland emissions are the dominant driver in the 𝛿13C seasonal cycle in the Northern Hemisphere and Tropics, such that the timing of 𝛿13C seasonal minimum is shifted by ∼90 days in 60° N–90° N from the end of the year to the beginning of the year when seasonality of wetland emissions is removed. The results also showed that in the Southern Hemisphere Tropics, emissions from fires contribute to the enrichment of 𝛿13C in July–October. In addition, we also compared the results against observations from the South Pole, Antarctica, Alert, Nunavut, Canada and Niwot Ridge, Colorado, USA. In light of this research, comparison to the observation showed that the seasonal cycle of EFMM emissions in EDGAR v5.0 inventory is more realistic than in v4.3.2. In addition, the comparison at Alert showed that modelled 𝛿13C amplitude was approximately half of the observations, mainly because the model could not reproduce the strong depletion in autumn. This indicates that CH4 emission magnitude and seasonal cycle of wetlands may need to be revised. Results from Niwot Ridge indicate that in addition to biogenic emissions, the proportion of biogenic to fossil based emissions may need to be revised.