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A 3.0 GHz pulsed microwave source operated at atmospheric pressure with a pulse power of 1.4 MW, a maximum repetition rate of 40 Hz, and a pulse length of 3.5 µs is experimentally studied with respect to the ability to remove NO x from synthetic exhaust gases. Experiments in gas mixtures containing N 2 /O 2 /NO with typically 500 ppm NO are carried out. The discharge is embedded in a high-Q microwave resonator, which provides a reliable plasma ignition. Vortex flow is applied to the exhaust gas to improve gas treatment. Concentration measurements by Fourier transform infrared spectroscopy confirm an NO x reduction of more than 90% in the case of N 2 /NO mixtures. The admixture of oxygen lowers the reductive potential of the reactor, but NO x reduction can still be observed up to 9% O 2 concentration. Coherent anti-Stokes Raman scattering technique is applied to measure the vibrational and rotational temperature of N 2 . Gas temperatures of about 400 K are found, whilst the vibrational temperature is 3000-3500 K in pure N 2 . The vibrational temperature drops to 1500 K when O 2 and/or NO are present. The randomly distributed relative frequency of occurrence of selected breakdown field intensities is measured by a calibrated, short linear-antenna. The breakdown field strength in pure N 2 amounts to 2.2 × 10 6 V m −1 , a value that is reproducible within 2%. In the case of O 2 and/or NO admixture, the frequency distribution of the breakdown field strength scatters more and extends over a range from 3 to 8 × 10 6 V m −1 .

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A multidisciplinary approach involving organic synthesis and theoretical chemistry is applied to investigate a promising strategy to improve charge separation in organic photovoltaics:installing permanent dipoles in fullerene derivatives. Firstly, a PCBM analogue with a permanent dipole in the side-chain (PCBDN) and its reference analogue without a permanent dipole (PCBBz) were successfully synthesised and characterised. Secondly, a multiscale modelling approach was applied to investigate if a PCBDN environment around a central donor-acceptor complex indeed facilitates charge separation. Alignment of the embedding dipoles in response to charges present on the central donor-acceptor complex enhances charge separation. The good correspondence between experimentally and theoretically determined electronic and optical properties of PCBDN, PCBBz and PCBM indicates that the theoretical analysis of the embedding effects of these molecules gives a reliable expectation for their influence on the charge separation process at a microscopic scale in a real device.This work suggests the following strategies to improve charge separation in organic photovoltaics: installing permanent dipoles in PCBM analogues and tuning the concentration of these molecules in an organic donor/acceptor blend.3

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