On volatile/mobile trace element trends in E3 chondrites

Contents of 3 non-mobile trace elements (U, Co, Au) and 12 slightly-to-highly volatile ones (Rb, Sb, Ag, Ga, Se, Cs, Te, Zn, Cd, Bi, Tl and In) determined by RNAA in the Yamato (Y)-691 and Qingzhen E3 chondrites generally fall within ranges reported for E4 chondrite falls. Contents of most elements are similar in the two E3 chondrites : highly volatile Cd, Bi and Tl differ markedly, with the Y-691 data falling at C1 levels and those of Qingzhen near the bottom of the E4 ranges. Trace element abundances and interelement comparisons indicate that both E3 chondrites compositionally reflect only nebular condensation, with Y-691 parent material having condensed at lower temperatures than Qingzhen. Both escaped the post-accretionary metamorphic episode that compositionally altered other enstatite chondrites. For volatiles, E3,4 chondrites differ markedly from E5,6 : for siderophiles, E3-5 differ markedly from E6. These trends could reflect enstatite chondrites\u27 origin in 1 or 2 parent bodies : we interpret the data as indicating a single body

Trace element analysis of L and LL chondrites: Comparison of Antarctic and non-Antarctic meteorite populations

Since 1969, over 7000 meteorite fragments (representing at least 1200 separate events) have been found in Antarctica. They are important not only because of their large numbers, but also for their complement of rare and unique specimens and their long terrestrial ages (up to 10\sp6 years) compared to non-Antarctic falls (typically $\u3c$200 years). We report compositional data for mobile/volatile trace elements Au, Co, Se, Ga, Rb, Cs, Te, Bi, In, Ag, Zn, Tl and Cd in Antarctic L chondrites and both Antarctic and non-Antarctic LL chondrites. A comparison of previously obtained non-Antarctic L chondrite data to L chondrite results obtained in this work indicates that significant reason exists to doubt that the two meteorite populations derived from the same parent source. Of the 13 trace elements examined, 7 showed statistically significant differences between mildly-shocked populations; the Antarctic collection had the lower mean elemental concentration in each of those 7 cases. Two-element plots and correlation profiles also indicated significant differences between Antarctic and non-Antarctic populations. Shock-induced trace element mobilization, a major determinant of trace element contents in non-Antarctic L chondrites, plays a minor role in determining elemental abundances in Antarctic L chondrites. After ruling out alternate explanations, we believe these differences to have a preterrestrial origin and attribute them to a changing meteorite flux with time. Due to a lack of available samples, the LL chondrite study was inconclusive. Our data are consistent with previous findings which suggest Yamato Mts. and Victoria Land samples may be compositionally different. A positive correlation between trace element content and petrologic type was observed in LL chondrites. Whether this unexpected finding is due to a unique shock history of LL4 + 5 chondrites or some other explanation is unclear; more samples must be analyzed and shock facies must be obtained to further investigate this finding. Shock-induced trace element mobilization was found to be a minor factor in determining trace element content in LL chondrites

Yamato-791197: A volatile trace element rich lunar highlands sample from Antarctica

Neutron activation analysis of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U and Zn in Yamato-791197 reveals that many elements are enriched and heterogeneously distributed compared with Allan Hills A81005. While both samples derive from the lunar highlands, perhaps the same region, they were never part of the same rock. Trace element contents in Y-791197 resemble those in Apollo 66095 ("Rusty Rock"), a unique sample rich in condensed lunar volcanic exhalation

Volatile chalcophile, siderophile and lithophile trace elements in lunar meteorite Yamato-82192

Neutron activation analyses of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U and Zn in whole-rock, melted and unmelted regolith samples of Yamato-82192 reveals a lunar highlands origin plus meteorite admixture, 2.4±0.8% Cl-equivalent for micrometeorites and ancient impact component. A small but real amount of mobile element loss occurred during the shock-melting episode that formed Y-82192. Differences in trace element and other trends indicate pronounced differences in the thermal histories of the parent regoliths of Allan Hills A81005 and Y-791197 and -82192 so that each must have been produced by a separate impact on the Moon

Improved reproducibility of metal halide perovskite solar cells via automated gas quenching

Achieving reproducible perovskite solar cell fabrication is crucial for making it a scalable technology. We demonstrate an automated gas quenching system to improve perovskite solar cell reproducibility at the lab-scale. We use in situ photoluminescence to monitor the perovskite film formation as a function of the atmosphere in the glove box and find that antisolvent quenching is more sensitive to lingering precursor solvents than the gas quenching method. We observe a better reproducibility with gas quenching than with antisolvent quenching because it maintains a more consistent atmosphere in the glove box. The automated gas quenching process leads to high performing devices that are reproducible both batch to batch and researcher to researcher. The insights into gas quenching film formation as a function of solvent atmosphere and quench velocity will help inform future studies on large scale fabrication systems