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The most efficient and stable perovskite solar cells (PSCs) are made from a complex mixture of precursors. Typically, to then form a thin film, an extreme oversaturation of the perovskite precursor is initiated to trigger nucleation sites, e.g., by vacuum, an airstream, or a so-called antisolvent. Unfortunately, most oversaturation triggers do not expel the lingering (and highly coordinating) dimethyl sulfoxide (DMSO), which is used as a precursor solvent, from the thin films; this detrimentally affects long-term stability. In this work, (the green) dimethyl sulfide (DMS) is introduced as a novel nucleation trigger for perovskite films combining, uniquely, high coordination and high vapor pressure. This gives DMS a universal scope: DMS replaces other solvents by coordinating more strongly and removes itself once the film formation is finished. To demonstrate this novel coordination chemistry approach, MAPbI3 PSCs are processed, typically dissolved in hard-to-remove (and green) DMSO achieving 21.6% efficiency, among the highest reported efficiencies for this system. To confirm the universality of the strategy, DMS is tested for FAPbI3 as another composition, which shows higher efficiency of 23.5% compared to 20.9% for a device fabricated with chlorobenzene. This work provides a universal strategy to control perovskite crystallization using coordination chemistry, heralding the revival of perovskite compositions with pure DMSO.

All-inorganic perovskites have emerged as promising photovoltaic materials due to their superior thermal stability compared to their heat-sensitive hybrid organic-inorganic counterparts. In particular, CsPbI2 Br shows the highest potential for developing thermally-stable perovskite solar cells (PSCs) among all-inorganic compositions. However, controlling the crystallinity and morphology of all-inorganic compositions is a significant challenge. Here, a simple, thermal gradient- and antisolvent-free method is reported to control the crystallization of CsPbI2 Br films. Optical in situ characterization is used to investigate the dynamic film formation during spin-coating and annealing to understand and optimize the evolving film properties. This leads to high-quality perovskite films with micrometer-scale grain sizes with a noteworthy performance of 17% (≈16% stabilized), fill factor (FF) of 80.5%, and open-circuit voltage (VOC ) of 1.27 V. Moreover, excellent phase and thermal stability are demonstrated even after extreme thermal stressing at 300 °C.

Engineering construction involves many internal factors and external environmental factors, resulting in conflict or uncoordinated problems in engineering management. The harmonious management of engineering construction is the process of coordinating and solving the contradiction between construction elements and the problems between them and the external environment. The connotations of three subsystems of engineering harmony, namely, Ren harmony (RH), Wu harmony (WH), and Shi harmony (SH), are defined, and the system architecture of engineering harmony is constructed. Then, a hypothetical model is proposed to deeply explore the impacts of subsystems such as Ren harmony, Wu harmony, and Shi harmony on engineering harmony, as well as the moderating effects of the natural ecology, social humanities, and political economy on engineering harmony. The results show that (1) natural ecology has a significant promotion effect on RH, SH, and engineering harmony; (2) social humanities have a significant enhancement effect on SH and engineering harmony; and (3) political economy does not play a significant role in any process. "Engineering harmony" is used to measure the effectiveness of engineering management, and a scientific scale is used to reflect this index. It provides a new idea for theoretical exploration and practical guidance in engineering construction management. [ABSTRACT FROM AUTHOR]

In recent years, impulse buying is increasingly common in China. Online impulse buying (OIB) has drawn increasing scholarly attention across disciplines. This study focuses on the impulse buying of “Double 11” Shopping Carnival, taking “Double 11” Shopping Carnival consumers as research object, through related theory, secondary data analysis and social network analysis, exploring the relationship between marketing stimulation, impulse buying and emotional response, and establish a theoretical model and propose hypotheses. Data were obtained form 325 consumers. According to the statistical analysis result, the paper demonstrates that the theoretical model verifies the consumers’ impulsive buying can make a mediating effect between marketing stimulation and happy emotion, emotion of guilty, regretful emotion. In summary, this study made some marketing suggestions for the enterprises, including the utility of different ways to cause different kinds of emotions after impulsive buying for consumers.

Objective To systematically review the clinicopathological and prognostic value of circulating tumor cells (CTCs) in peripheral blood (PB) in head and neck cancer patients by meta-analysis. Methods We electronically searched PubMed, EmBase, Cochrane Library, CBM, CNKI and Wanfang database for collecting the studies about the clinicopathological and prognostic relevance of CTCs in PB in head and neck cancer patients (from inception to March 2018).Two researchers screened the literatures according to the inclusion and exclusion criteria, and further extracted the data and evaluated the quality.Stata 12.0 software was used for this analysis. Results A total of 18 studies (English:17; Chinese:1) involving 779 patients with head and neck cancer were eligible for the final analyses.The pooled results showed CTCs-positive in PB was significantly associated with poorer overall survival (OS) (P=0.006), disease-free survival (DFS) (P < 0.001) and progression-free survival (PFS) (P=0.008).And, the risk of recurrence in CTCs-positive patients was significantly higher than that in CTCs-negative patients (P=0.022).Furthermore, CTCs-positive in PB showed a significantly positive correlation with T stage (P=0.028), N stage (P=0.016) and TNM stage (P=0.024) of head and neck cancer, rather than age, gender or tumor histological grade. Conclusion CTCs detected from PB has significantly prognostic value for the patients with head and neck cancer, and CTCs-positive indicates poor prognosis.