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Halide perovskites have attracted substantial interest for their potential as disruptive display and lighting technologies. However, perovskite light-emitting diodes (PeLEDs) are still hindered by poor operational stability. A fundamental understanding of the degradation processes is lacking but will be key to mitigating these pathways. Here, we use a combination of in operando and ex-situ measurements to monitor the performance degradation of (Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3 PeLEDs over time. Through device, nanoscale cross-sectional chemical mapping, and optical spectroscopy measurements, we reveal that the degraded performance arises from an irreversible accumulation of bromide content at one interface, which leads to barriers to injection of charge carriers and thus increased non-radiative recombination. We impede this ionic segregation by passivating the perovskite films with potassium halides, which immobilizes the excess halide species. The passivated PeLEDs show enhanced external quantum efficiency (EQE) from 0.5 to 4.5% and, importantly, show significantly enhanced stability, with minimal performance roll-off even at high current densities (> 200 mA/cm2). The decay half-life for the devices under continuous operation at peak EQE increases from

Halide perovskites have remarkable properties for relatively crudely processed semiconductors, including large optical absorption coefficients and long charge carrier lifetimes. Thanks to such properties, these materials are now competing with established technologies for use in cost-effective and efficient light harvesting and light emitting devices. Nevertheless, our fundamental understanding of the behaviour of charge carriers in these materials particularly on the nano to micro scale has on the whole lagged behind the empirical device performances. Such understanding is essential to control charge carriers, exploit new device structures, and push devices to their performance limits. Among other tools, optical microscopy and spectroscopic techniques have revealed rich information about charge carrier recombination and transport on important length scales. In this Progress Report, we detail the contribution of time-resolved optical microscopy techniques to our collective understanding of the photophysics of these materials. We discuss ongoing technical developments in the field that are overcoming traditional experimental limitations in order to visualise transport properties over multiple time and length scales. Finally, we propose strategies to combine optical microscopy with complementary techniques in order to obtain a holistic picture of local carrier photophysics in state of the art perovskite devices., Progress report article

Objective: Memory deficits in patients with frontal lobe lesions are most apparent on free recall tasks that require the selection, initiation, and implementation of retrieval strategies. The effect of frontal lesions on recognition memory performance is less clear with some studies reporting recognition memory impairments but others not. The majority of these studies do not directly compare recall and recognition within the same group of frontal patients, assessing only recall or recognition memory performance. Other studies that do compare recall and recognition in the same frontal group do not consider recall or recognition tests that are comparable for difficulty. Recognition memory impairments may not be reported because recognition memory tasks are less demanding. Method: This study aimed to investigate recall and recognition impairments in the same group of 47 frontal patients and 78 healthy controls. The Doors and People Test was administered as a neuropsychological test of memory as it assesses both verbal and visual recall and recognition using subtests that are matched for difficulty. Results: Significant verbal and visual recall and recognition impairments were found in the frontal patients. Conclusion: These results demonstrate that when frontal patients are assessed on recall and recognition memory tests of comparable difficulty, memory impairments are found on both types of episodic memory test.

Common sense suggests and research indicates relationships between staff factors in residential dementia care and the quality of life for residents, with poor care increasing resident suffering. However, we do not have a coherent picture of which interventions with staff have a sustained impact on quality of care and consequent resident quality of life. From a comprehensive search of published peer-reviewed literature from the last 20 years, only 44 studies met the inclusion criteria. Conclusions from these limited data are further compromised because a quarter of the studies failed to measure effects on residents and only half overall assessed effects after the project team withdrew. Of those that did, excellent studies produced change over the medium or longer term, including reduction in challenging behaviour and restraint use but this applied only to a significant minority. A number of studies failed to measure effects on quality of care, limiting conclusions about the mechanisms underlying change. Generally, level of intervention required depended on the target. For outcomes like restraint use, structured education sessions with some support appear adequate. For complicated issues like challenging behaviours, detailed, long-term, supportive, on-site interventions are required. The most promising findings were improvements in restraint and staff/resident interactions.

Transactions of the Cumberland & Westmorland Antiquarian & Archaeological Society, 66, 220-247