Testing the daytime oxidizing capacity of the troposphere: 1994 OH field campaign at the Izaña Observatory, Tenerife

A field campaign was carried out during May 1994 at the Izaña station, Tenerife. This campaign was part of the program Environment and Climate sponsored by the European Commission to study the influence of European emissions on the oxidizing capacity of a clean tropospheric environment. Daytime and also nighttime measurements were made, covering the OH as well as the NO3 chemistry. This paper presents the OH measurements taken with a multipass optical absorption spectrometer (MOAS) and discusses the daytime chemistry in a statistical and therefore more preliminary way. All relevant parameters influencing the OH concentration were monitored. From the data the two main contributions to the OH production can clearly be discerned and are given by the primary production following the ozone photolysis and the O(1D)-H2O reaction and by the catalytic reactions of NOx in the recycling process. The latter processes prove to contribute a dominant part to the OH concentration. The measurements of the nonmethane hydrocarbons (NMHC) especially of the biogenics, indicate a considerable influence of the NMHC on the absolute values of the OH concentration at Tenerife.This work has been financially supported by the European Commission (grant EV5V-CT93-0321), by the DFG, and by the Fonds der Chemischen Industrie, which is gratefully acknowledged

Dynamic mechanisms of He single ionization by fast proton impact

Triple-differential ionization cross sections 3 pdcphipdprec, the momentum distributions of singly charged recoil ions transverse to the beam direction as a function of the projectile polar (p), and azimuthal (cphip) scattering angle were measured in order to elucidate the dynamics of 3-MeV H+ on He single ionization. For projectile polar deflections 0.2 p1 mrad and azimuthal scattering angles 0°cphip360°, the kinematic regimes where two-body interactions dominate the three-body momentum exchange of the single-ionization reaction were separated experimentally. © 1992 The American Physical Society

Utilizing the unique charge extraction properties of antimony tin oxide nanoparticles for efficient and stable organic photovoltaics

Simultaneously enhancing device performance and longevity, as well as balancing the requirements on cost, scalability, and simplification of processing, is the goal of interface engineering of organic solar cells (OSCs). In our work, we strategically introduce antimony (Sb3+) cations into an efficient and generic n-type SnO2 nanoparticles (NPs) host during the scalable flame spray pyrolysis synthesis. Accordingly, a significant switch of conduction property from an n-type character to a p-type character is observed, with a corresponding shift in the work function (WF) from 4.01 ± 0.02 eV for pristine SnO2 NPs to 5.28 ± 0.02 eV for SnO2 NPs with 20 mol. % Sb content (ATO). Both pristine SnO2 and ATO NPs with fine-tuned optoelectronic properties exhibit remarkable charge carrier extraction properties, excellent UV resistance and photo-stability being compatible with various state-of-the-art OSCs systems. The reliable and scalable pristine SnO2 and ATO NPs processed by doctor-blading in air demand no complex post-treatment. Our work offers a simple but unique approach to accelerate the development of advanced interfacial materials, which could circumvent the major existing interfacial problems in solution-processed OSCs

Utilizing the unique charge extraction properties of antimony tin oxide nanoparticles for efficient and stable organic photovoltaics

Simultaneously enhancing device performance and longevity, as well as balancing the requirements on cost, scalability, and simplification of processing, is the goal of interface engineering of organic solar cells OSCs . In our work, we strategically introduce antimony Sb3 cations into an efficient and generic n type SnO2 nanoparticles NPs host during the scalable flame spray pyrolysis synthesis. Accordingly, a significant switch of conduction property from an n type character to a p type character is observed, with a corresponding shift in the work function WF from 4.01 0.02 eV for pristine SnO2 NPs to 5.28 0.02 eV for SnO2 NPs with 20 mol. Sb content ATO . Both pristine SnO2 and ATO NPs with fine tuned optoelectronic properties exhibit remarkable charge carrier extraction properties, excellent UV resistance and photo stability being compatible with various state of the art OSCs systems. The reliable and scalable pristine SnO2 and ATO NPs processed by doctor blading in air demand no complex post treatment. Our work offers a simple but unique approach to accelerate the development of advanced interfacial materials, which could circumvent the major existing interfacial problems in solution processed OSC

Eastern Atlantic Spring Experiment 1997 (EASE97): 1. Measurements of OH and HO2 concentrations at Mace Head, Ireland

We report measurements of the hydroxyl (OH) and hydroperoxy (HO2) radicals, taken over 20 days, in the remote marine boundary layer at Mace Head, Ireland, during April and May 1997. OH was monitored directly by laser-induced fluorescence (LIF) spectroscopy at 308 nm, and HO2 was measured by chemical conversion to OH upon the addition of NO, with subsequent detection by LIF. The detection limit of the instrument at midday for OH was 6.0 × 105 molecule cm−3 (0.0024 parts per trillion by volume (pptv)) and for HO2 was 3.0 × 106 molecule cm−3 (0.12 pptv), as defined for a signal integration period of 2.5 min and a signal-to-noise ratio of 1. Midday OH and HO2 concentrations were between 2.0–6.0 × 106 molecule cm−3 (0.08–0.24 pptv) and 0.5–3.5 × 108 molecule cm−3 (2.5–14 pptv), respectively. OH concentrations correlated well with the rate of OH production from ozone photolysis for clean air from the Arctic containing low concentrations of both NOx and nonmethane hydrocarbons. A lower correlation was observed in more polluted air that originated from the United Kingdom and continental Europe. Measurements of OH and HO2 were made throughout two nights, and although no evidence was seen for OH above the detection limit, up to 2 pptv of HO2 was observed. The measured HO2/OH ratio was in good agreement with the predictions of a steady state expression for NO in the range 75–400 pptv