Organometal mixed-halide perovskite materials hold great promise for next-generation solar cells, light-emitting diodes, lasers, and photodetectors. Except for the rapid progress in the efficiency of perovskite-based devices, the stability issue over prolonged light illumination has severely hindered their practical application. The deterioration mechanism of organometal halide perovskite materials under light illumination has seldom been conducted to date, which is indispensable to the understanding and optimization of photon-harvesting process inside perovskite-based optoelectronic devices. Here, explicit degradation pathways and comprehensive microscopic understandings of white-light-induced degradation have been put forward for two organometal mixed-halide perovskite materials (e.g., MAPbICl and MAPbBrCl) under high vacuum conditions. In situ compositional analysis and real-time film characterizations reveal that the decomposition of both mixed-halide perovskites starts at the grain boundaries, leading to the formation of hydrocarbons and ammonia gas with the residuals of PbI(Cl), Pb, or PbClBr in the films. The degradation has been correlated to the localized trap states that induce strong coupling between photoexcited carriers and the crystal lattice.

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This article traces the progress of the open method of co-ordination in research policy, and examines one of its strands, the Mobility Strategy, as a 'best practice' OMC. Despite the critical analyses it has received to date, we argue that the OMC has shown the potential to impact on national systems and achieve convergence, albeit not necessarily of a quantitative kind. Under the Ljubljana Process, the OMC has been confirmed as the central method of governance to further develop the European research area and here we put forward several recommendations for its future application. Copyright (c) 2010 The Author(s). Journal compilation (c) 2010 Blackwell Publishing Ltd.

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