Optimizing properties of phosphors for use in white-light-emitting diodes (WLEDs) is an important materials challenge. Most phosphors have a low level of lattice disorder due to mismatch between the host and activator cations. Here we show that deliberate introduction of high levels of cation disorder leads to significant improvements in quantum efficiency, stability to thermal quenching, and emission lifetime in Sr(CaBa)SiN:Eu (x = 0-1.5) phosphors. Replacing Sr by a (CaBa) mixture with the same average radius increases cation size variance, resulting in photoluminescence emission increases of 20-26% for the x = 1.5 sample relative to the x = 0 parent across the 25-200 °C range that spans WLED working temperatures. Cation disorder suppresses nonradiative processes through disruption of lattice vibrations and creates deep traps that release electrons to compensate for thermal quenching. Introduction of high levels of cation disorder may thus be a very useful general approach for improving the efficiency of luminescent materials.

SUMMARY The Inter-Regional Epidemiological Study of Childhood Cancer (IRESCC) collected interview and medical information relating to the child's past medical experiences from parents of 555 children diagnosed with cancer and parents of 1110 unaffected matched controls. No significant associations emerged overall for ante-natal care, place and mode ofdelivery, length ofgestation, birth weight, condition at birth, special care, neonatal procedures or breast-feeding. Few risk factors relating to previous illnesses and medication were found, although increasing numbers of illnesses appeared to be associated with an increased risk of childhood cancer, particularly acute lymphoblastic leukaemia. A highly significant excess of case children had not been immunised (p = 0 005). In general, these results indicate that past medical experiences have little influence on the development of cancer in children.

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. (2016) '3D transition metal ordering and Rietveld stacking fault quantication in the new oxychalcogenides La2O2Cu24xCd2xSe2.', Chemistry of materials., 28 (9). pp. 3184-3195. Further information on publisher's website:http://dx.doi.org/10.1021/acs.chemmater.6b00924 Publisher's copyright statement: This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Chemistry of Materials, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/acs.chemmater.6b00924].Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. 1+ and Cd 2+ ions segregate into distinct fully occupied and half occupied checkerboard-like layers respectively, leading to complex long-range superstructures in the 3rd (stacking) dimension. To understand the structure and microstructure of these new materials we have developed and implemented a new methodology for studying low and high probability stacking faults using a Rietveldcompatible supercell approach capable of analyzing systems with thousands of layers. We believe this method will be widely applicable.