The low toxicity and a near-ideal choice of bandgap make tin perovskite an attractive alternative to lead perovskite in low cost solar cells. However, the development of Sn perovskite solar cells has been impeded by their extremely poor stability when exposed to oxygen. We report low-dimensional Sn perovskites that exhibit markedly enhanced air stability in comparison with their 3D counterparts. The reduced degradation under air exposure is attributed to the improved thermodynamic stability after dimensional reduction, the encapsulating organic ligands, and the compact perovskite film preventing oxygen ingress. We then explore these highly oriented low-dimensional Sn perovskite films in solar cells. The perpendicular growth of the perovskite domains between electrodes allows efficient charge carrier transport, leading to power conversion efficiencies of 5.94% without the requirement of further device structure engineering. We tracked the performance of unencapsulated devices over 100 h and found no appreciable decay in efficiency. These findings raise the prospects of pure Sn perovskites for solar cells application.

Aim: Resilience refers to positive adaption in the face of stress or trauma. Assessing resilience is crucial in trauma-related research and practice. The 10-item Connor-Davidson Resilience Scale (CD-RISC) has been demonstrated to be a valid and reliable tool to achieve this goal. This study was designed to examine the psychometric properties of the 10-item CD-RISC in a sample of Chinese earthquake victims.Methods: A total of 341 participants (185 women, 156 men) aged 20-63 years were recruited from a psychological relief program supported by the Institute of Psychology, Chinese Academy of Sciences following the 'Wenchuan' earthquake. The participants were given the 10-item CD-RISC and the 17-item post-traumatic stress disorder (PTSD) subscale of the Los Angeles Symptom Checklist (LASC) 4 months after the earthquake. Results:The results of exploratory factor analysis indicated that a single-factor model consistent with the original design of the 10-item CD-RISC was support. The scale was also demonstrated to have good internal consistency (Cronbach's alpha = 0.91) and test-retest reliability (r = 0.90 for a two-week interval). Scores on the scale could reflect different levels of resilience in populations that are thought to be differentiated (probable PTSD vs healthy controls, t(339) = -7.60, P < 0.01, Cohen's d = 0.84). Moreover, the total resilience scores were significantly negatively correlated with scores on total PTSD scale and its three subscales for all participants. Conclusion:The Chinese version of the 10-item CD-RISC has excellent psychometric properties, and is applicable for Chinese people.

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BackgroundOn May 12, 2008, a destructive earthquake registering 8.0 on the Richter scale struck Sichuan Province, southwest China. Beichuan County was the epicenter which was one of the areas nearly completely destroyed by the earthquake. In Beichuan, about 15000 people died and 3000 people were missing. Specially, the earthquake took 1587 students' and 214 teachers' lives from the elementary and middle schools there. The main purpose of the study was to provide a better understanding of mental health problems and associated risk factors among children after earthquake.MethodThree hundred and thirty grades 3–5 children completed the questionnaire of disaster –related experience and the Trauma Symptom Checklist for Children-Alternate Version (TSCC-A). The first survey was carried out six months after the earthquake, and the second one was carried out six months later. The measurements and methodology applied in the two sessions were identical.ResultsThe prevalence rates of the problems at two time-points were 23.3% and 22.7% for anxiety, 14.5% and 16.1% for depression, and 11.2% and 13.4% for PTSD, respectively. Among demographic variables, no significant age difference existed, while it was found that 6 months after the earthquake, symptoms of anxiety, depression and PTSD were significantly more common among students in grades 4 and 5 than those in grade 3, Initial exposure to death, bereavement and extreme fear were significant predictive factors for the occurrence of anxiety, depression and PTSD.ConclusionsFindings of this study suggest that posttraumatic mental health problems after natural disaster in children may have reached epidemic proportions and remain high for a long period. Psychologist and social workers should pay more attention to children who experienced more traumatic stresses and provide appropriate mental health interventions. Implications and limitations of these findings were discussed.