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Here efficient organic photovoltaic devices fabricated from water-based colloidal dispersions with donor:acceptor composite nanoparticles achieving up to 9.98% power conversion efficiency (PCE) are reported. This high efficiency for water processed organic solar cells is attributed to morphology control by surface energy matching between the donor and the acceptor materials. Indeed, due to a low interfacial energy between donor and the acceptor, no large phase separation occurs during the nanoparticle formation process as well as upon thermal annealing. Indeed, synchrotron-based scanning transmission X-ray microscopy reveals that the internal morphology of composite nanoparticles is intermixed as well as the active layer morphology after thermal treatment. The PCE of this system reaches 85% that of devices prepared from chlorinated solvent. The gap between water-based inks and organic solvent-based inks gets narrower, which is promising for the development of eco-friendly processing and fabrication of organic photovoltaics.

We report, for the first time, sub-4 nm mapping of donor : acceptor nanoparticle composition in eco-friendly colloidal dispersions for organic electronics. Low energy scanning transmission electron microscopy (STEM) energy dispersive X-ray spectroscopy (EDX) mapping has revealed the internal morphology of organic semiconductor donor : acceptor blend nanoparticles at the sub-4 nm level. A unique element was available for utilisation as a fingerprint element to differentiate donor from acceptor material in each blend system. Si was used to map the location of donor polymer PTzBI-Si in PTzBI-Si:N2200 nanoparticles, and S (in addition to N) was used to map donor polymer TQ1 in TQ1:PC71BM nanoparticles. For select material blends, synchrotron-based scanning transmission X-ray microscopy (STXM), was demonstrated to remain as the superior chemical contrast technique for mapping organic donor : acceptor morphology, including for material combinations lacking a unique fingerprint element (e.g. PTQ10:Y6), or systems where the unique element is in a terminal functional group (unsaturated, dangling bonds) and can hence be easily damaged under the electron beam, e.g. F on PTQ10 donor polymer in the PTQ10:IDIC donor : acceptor blend. We provide both qualitative and quantitative compositional mapping of organic semiconductor nanoparticles with STEM EDX, with sub-domains resolved in nanoparticles as small as 30 nm in diameter. The sub-4 nm mapping technology reported here shows great promise for the optimisation of organic semiconductor blends for applications in organic electronics (solar cells and bioelectronics) and photocatalysis, and has further applications in organic core-shell nanomedicines.

The Homelessness Monitor series is a longitudinal study providing an independent analysis of the homelessness impacts of recent economic and policy developments in Wales and elsewhere in the UK. This fourth Wales-focused report provides an account of how homelessness stands in 2021 (or as close to 2021 as data availability allows), and covers a period dominated by the COVID-19 pandemic, as well as intense policy activity on homelessness in Wales. It is also the first Wales Monitor in which we offer detailed modelling estimates and forward projections of extreme forms of ‘core’ homelessness.

The Homelessness Monitor series is a longitudinal studyproviding an independent analysis of the homelessnessimpacts of recent economic and policy developmentsin Scotland and elsewhere in the UK.1 This fourthScotland-focused report provides an account of howhomelessness stands in 2021 (or as close to 2021 asdata availability allows), and covers a period dominatedby the COVID-19 pandemic, as well as intense policyactivity on homelessness in Scotland. It is also the firstScotland monitor in which we offer detailed modellingestimates and forward projections of extreme forms of‘core’ homelessness.

This study provides an independent analysis of the impact on homelessness from recent economic and policy developments in England. It considers the impact of housing market development and relevant policy innovations witnessed during the 2010s. This ninth annual report provides an account of how homelessness stands in England in 2020, and analyses key trends in the period running up to 2020. This year’s report focuses in particular on impacts associated with the COVID-19 pandemic. It draws on a cohort of local authority, government and NGO stakeholder interviews, as well as statistical and policy analysis. For the first time this year, it also includes homelessness projections.

This critical commentary reflects on a rapidly mobilised international podcast project, in which 25 urban scholars from around the world provided audio recordings about their cities during COVID-19. New digital tools are increasing the speeds, formats and breadth of the research and communication mediums available to researchers. Voice recorders on mobile phones and digital audio editing on laptops allows researchers to collaborate in new ways, and this podcast project pushed at the boundaries of what a research method and community might be. Many of those who provided short audio 'reports from the field' recorded on their mobile phones were struggling to make sense of their experience in their city during COVID-19. The substantive sections of this commentary discuss the digital methodology opportunities that podcasting affords geographical scholarship. In this case the methodology includes the curated production of the podcast and critical reflection on the podcast process through collaborative writing. Then putting this methodology into action some limited reflections on cities under COVID-19 lockdown and social distancing initiatives around the world are provided to demonstrate the utility and limitations of this method.

The rhetoric and practice of localism has attracted significant support within both political and academic circles in the UK in recent years. However, it is the contention of this article that there are, or should be, limits to localism as applied to the basic citizenship rights of vulnerable people. Drawing on a ten-year, mixed-methods study, we use the example of sharply rising homelessness in England to illustrate our argument that localist policymaking has an intrinsic tendency to disadvantage socially marginalised groups. While we acknowledge the central role played by austerity in driving up homelessness over the past decade, we advance the case that the post-2010 localist agenda of successive UK governments has also had an independent and malign effect. At the very least, we seek to demonstrate that localism cannot be viewed as a taken-for-granted progressive model, with centralism (that is, the consistent implementation of a policy across a whole country) also perfectly defensible on progressive grounds in relevant circumstances.