The growth of methylammonium lead iodide perovskites by close space vapor transport

Vapor deposition processes have shown promise for high-quality perovskite solar cells with potential pathways for scale-up to large area manufacturing. Here, we present a sequential close space vapor transport process to deposit CH₃NH₃PbI₃ (MAPI) perovskite thin films by depositing a layer of PbI₂ then reacting it with CH₃NH₃I (MAI) vapor. We find that, at T = 100 °C and pressure = 9 torr, a ∼225 nm-thick PbI₂ film requires ≥125 minutes in MAI vapor to form a fully-reacted MAPI film. Raising the temperature to 160 °C increases the rate of reaction, such that MAPI forms within 15 minutes, but with reduced surface coverage. The reaction kinetics can be approximated as roughly first-order with respect to PbI₂, though there is evidence for a more complicated functional relation. Perovskite films reacted at 100 °C for 150 minutes were fabricated into solar cells with an SLG/ITO/CdS/MAPI/Spiro-OMeTAD/Au structure, and a device efficiency of 12.1% was achieved. These results validate the close space vapor transport process and serve as an advance toward scaled-up, vapor-phase perovskite manufacturing through continuous vapor transport deposition.

This is the first demonstration of an all-vapor close space vapor transport process to deposit methylammonium lead iodide perovskites.     

Clinical impairment in premanifest and early Huntington's disease is associated with regionally specific atrophy

TRACK‐HD is a multicentre longitudinal observational study investigating the use of clinical assessments and 3‐Tesla magnetic resonance imaging as potential biomarkers for future therapeutic trials in Huntington's disease (HD). The cross‐sectional data from this large well‐characterized dataset provide the opportunity to improve our knowledge of how the underlying neuropathology of HD may contribute to the clinical manifestations of the disease across the spectrum of premanifest (PreHD) and early HD. Two hundred and thirty nine gene‐positive subjects (120 PreHD and 119 early HD) from the TRACK‐HD study were included. Using voxel‐based morphometry (VBM), grey and white matter volumes were correlated with performance in four domains: quantitative motor (tongue force, metronome tapping, and gait); oculomotor [anti‐saccade error rate (ASE)]; cognition (negative emotion recognition, spot the change and the University of Pennsylvania smell identification test) and neuropsychiatric measures (apathy, affect and irritability). After adjusting for estimated disease severity, regionally specific associations between structural loss and task performance were found (familywise error corrected, P < 0.05); impairment in tongue force, metronome tapping and ASE were all associated with striatal loss. Additionally, tongue force deficits and ASE were associated with volume reduction in the occipital lobe. Impaired recognition of negative emotions was associated with volumetric reductions in the precuneus and cuneus. Our study reveals specific associations between atrophy and decline in a range of clinical modalities, demonstrating the utility of VBM correlation analysis for investigating these relationships in HD. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.     

Does labeling matter? An examination of attitudes and perceptions of labels for mental disorders

Purpose

Labeling research in various domains has found that attitudes and perceptions vary as a function of the different labels ascribed to a group (e.g., overweight vs. obese). This type of research, however, has not been examined extensively in regards to labels for mental disorders. The present study examined whether common psychiatric labels (i.e., mental disease, mental disorders, mental health problems, and mental illness) elicited divergent attitudes and perceptions in a group of participants. These labels were also compared to the specific label of depression.

Methods

Undergraduate psychology students (N = 124) were given identical questionnaire packages with the exception of the label used. That is, each participant received a set of questionnaires that referred to only one of the five labels. The questionnaire package contained various quantitative measures of attitudes and social distance, in addition to a short qualitative measure.

Results

Analyses demonstrated equivalence among the four general psychiatric labels on measures of attitudes, social distance, and general perceptions. However, results also suggested that the general labels diverged from the depression label, with the latter being generally more negatively perceived. Some analyses demonstrated that participants’ understanding of the terminology might be incorrect. The results of the investigation are discussed with a focus on its relationship with current research in stigma.

Conclusion

Within the current sample, general psychiatric labels did not appear to distinguish themselves from each other on measures of attitude and social distance but did so when compared to a relatively more specific term. Future research should examine the underlying mechanism driving this finding, with the ultimate goal of reducing the stigma faced by those with mental disorders.