http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12495 A series of three porphyrins varying only in the steric bulk of their peripheral groups have been synthesised and integrated into the active layer of bulk heterojunction solar cells. The porphyrins broaden the spectral response of the device and contribute to the total photocurrent generated. More importantly, the device characteristics change systematically with increasing steric bulk on the peripheral meso phenyl groups of the tetra-phenyl porphyrin. Optical, scanning probe and scanning transmission X-ray microscopy are used to demonstrate that the observed changes do not arise from morphological differences in film structure. Cyclic voltammetry, UV–vis spectroscopy and DFT calculations are used to establish that the porphyrin LUMO, HOMO and bandgap are independent of side group. We conclude that the variations in open-circuit voltage with side group are the result of the porphyrin acting as a bimolecular recombination centre, with an efficiency that is dependent on the side group type. The possibility of designing optimised macromolecules for OPV devices based on an understanding the effect of porphyrin steric bulk upon device performance is discussed. 2013-01-29T05:50:04.857Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:565 In this paper we investigate the propagation of long-term climate variabilities and climate changes through a catchment system to the flood frequency curve, through the use of a rainfall-runoff model that captures rainfall and water balance variability at a multiplicity of time scales, ranging from event to seasonal, inter-annual and inter-decadal time scales. This modelling investigation is carried out in the Susannah Brook catchment, Western Australia. Analysis of the results shows that, for example, a 10-year flood may change over to a 15-year flood over the next 50 years, due to a possible declining rainfall trend. Similarly, the 25-year flood may become a 40-year flood over the same period. These results suggest that engineers will need to come up with creative changes to traditional flood frequency estimation procedures to deal with long-term climate variability and changes. 2010-04-27T05:41:53.618Z ]]>