Surface Modification with CuFeS2 Nanocrystals to Improve the Efficiency and Stability of Perovskite Solar Cells.

Poor stability retards the industrialization of perovskite solar cells (PSCs). One of the effective ways to solve this issue is to modify the perovskite surface to improve the efficiency and stability of the PSCs. Herein, we synthesized CuFeS2 nanocrystals and applied them to modify the perovskite surface. The efficiency of the PSCs with CuFeS2 modification is improved to 20.17% from 18.64% for the control devices. Some investigations demonstrate that the CuFeS2 modification passivates the perovskite surface defects and induces better energy band arrangement. Furthermore, the stability of the PSCs with CuFeS2 modification is improved compared with the devices without CuFeS2 modification. The efficiency of the PSCs with CuFeS2 modification maintains 93% of its initial value, whereas that of the devices without CuFeS2 modification decreases to 61% of the initial value. This work demonstrates that CuFeS2 is a novel material used as a modification layer to enhance the efficiency and stability of the PSCs.

Analysis of clinical application effects and challenges of early warning system for the high-risk obstetric women of China: A scoping review.

BACKGROUND: Obstetric critical illness is an important factor that leads to an increase in maternal mortality. Early warning assessment can effectively reduce maternal and neonatal mortality and morbidity. However, there are multiple early warning systems, and the effect and applicability of each system in China still need to be explored. OBJECTIVES: To elaborate on the application, effectiveness and challenges of the existing early warning systems for high-risk obstetric women in China and to provide a reference for clinical practice. DESIGN: A scoping review guided by the Arksey and O'Malley framework and reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for scoping review (PRISMA-ScR) guidelines. ELIGIBILITY CRITERIA: We included original studies related to early warning and excluded those that were guidelines, consensus and reviews. The included studies were published in Chinese or English by Chinese scholars as of June 2021. DATA SOURCES: CNKI, Wanfang, VIP, Cochrane, CINAHL, Embase, PubMed and Web of Science databases were searched systematically, and the reference sections of the included papers were snowballed. RESULTS: In total, 598 articles were identified. These articles were further refined using keyword searches and exclusion criteria, and 17 articles met the inclusion criteria. We extracted data related to each study's population, methods and results. Early warning tools, outcome indices, effects and challenges are discussed. CONCLUSIONS: Although all studies have shown that early warning systems have good application effects, the use of early warning systems in China is still limited, with poor regional management and poor sensitivity for specific obstetric women. Future research needs to develop more targeted early warning tools for high-risk obstetric women and address the current challenges in clinical applications.

Career adaptability of newly graduated nurses at an obstetrics and gynaecology hospital in China: A qualitative study.

AIM: The aim of this study was to gain insight into factors affecting career adaptability of newly graduated nurses and ways to improve them. BACKGROUND: Newly graduated nurses face an important transition from student to professional. Unfortunately, the nurse turnover rate is high due to maladaptation. Factors influencing career adaptability and improvement methods have not been clearly addressed. METHODS: Using a descriptive qualitative study with thematic analysis, 15 newly graduated nurses from a tertiary obstetrics and gynaecology teaching hospital in China were interviewed. RESULTS: Six themes affecting career adaptability were found: personality, self-confidence, occupational care focus, work-related stress, basic professional competency and gap between reality and expectations. Four themes improving career adaptability were identified: strong social support, self-adjustment, self-development and career preparation. Eight subthemes were also identified. CONCLUSIONS: Individual, family and work factors were among those affecting career adaptability among newly graduated nurses. Newly graduated nurses would improve their career adaptability through self-adjustment and social support. Helping them to promote these factors and measures is conducive to improving their career adaptability and reducing staff turnover. IMPLICATIONS FOR NURSING MANAGEMENT: Nurse managers should be aware of the key factors affecting career adaptability among newly graduated nurses and design targeted improvement programmes.

Enhancement of Perovskite Solar Cells Efficiency using N-Doped TiO2 Nanorod Arrays as Electron Transfer Layer.

In this paper, N-doped TiO2 (N-TiO2) nanorod arrays were synthesized with hydrothermal method, and perovskite solar cells were fabricated using them as electron transfer layer. The solar cell performance was optimized by changing the N doping contents. The power conversion efficiency of solar cells based on N-TiO2 with the N doping content of 1% (N/Ti, atomic ratio) has been achieved 11.1%, which was 14.7% higher than that of solar cells based on un-doped TiO2. To get an insight into the improvement, some investigations were performed. The structure was examined with X-ray powder diffraction (XRD), and morphology was examined by scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) and Tauc plot spectra indicated the incorporation of N in TiO2 nanorods. Absorption spectra showed higher absorption of visible light for N-TiO2 than un-doped TiO2. The N doping reduced the energy band gap from 3.03 to 2.74 eV. The photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra displayed the faster electron transfer from perovskite layer to N-TiO2 than to un-doped TiO2. Electrochemical impedance spectroscopy (EIS) showed the smaller resistance of device based on N-TiO2 than that on un-doped TiO2.

[Dithiobis-succinimidyl propionate on gold island films: surface-enhanced infrared absorption spectroscopy study].

Dithiobis-succinimidyl propionate (DTSP), an important homobifunctional crosslinker, has been widely used for the covalent immobilization of proteins onto solid supports by amine coupling. In the present study, adsorption of DTSP on vacuum-deposited gold island films was analyzed by means of surface-enhanced infrared absorption spectroscopy (SEIRAS). For the sake of a reliable assignment of the vibrational spectra, IR intensity of the adsorption model of TSP on one gold surface was calculated using density functional theory (DFT) at the Beck' s three-parameter Lee-Yang-Parr (B3LYP) level with the LANL2DZ basis set. SEIRAS and multiple-angle-of-incidence polarization infrared reflection-absorption spectroscopy indicated that TSP is arranged orderly in a tilted fashion with a dihedral angle of 65 degrees between the plane of succinimidyl ring and the gold surface. The binding kinetics revealed that that the time constant of self-assembly of the TSP layer is 220 sec. Furthermore, the coupling process of amino-nitrilotriacetic acid (ANTA) with surface-bound TSP monolayer was monitored in situ by SEIRAS. Three negative bands observed at 1 807, 1 776, and 1 728 cm(-1) respectively provided direct evidence for the reaction of the succinimidyl ester. The appearance of one intense band at 1 566 cm(-1) gave a clear support for the presence of the cross-link between ANTA and TSP. We hope that the results in current investigation will contribute to the better understanding of properties of DTSP and related reactions at the molecular level.

Diaqua-bis-(1H-imidazole-κN(3))bis-(4-nitro-benzoato-κO(1))cadmium.

In the centrosymmetric title compound, [Cd(C(7)H(4)NO(4))(2)(C(3)H(4)N(2))(2)(H(2)O)(2)], the Cd(II) atom, located on an inversion center, is coordinated by two N atoms and four O atoms in an octa-hedral geometry. The inter-nal cohesion of the mol-ecule is enhanced by an intra-molecular O-H⋯O hydrogen bond. Inter-molecular O-H⋯O and C-H⋯O hydrogen bonds and π-π contacts [centroid-centroid distance = 3.6549 (2) Å] define two-dimensional networks parallel to (001), which are further connected by weaker C-H⋯O inter-actions into a weakly connected three-dimensional supra-molecular framework.

[Influence of K+ and Al3+ on the optical properties of Er3+ doped Sol-gel derived silica glasses].

Al3+ and K+ ions were introduced in Er(3+) -doped silica glass successfully through Sol-gel route. The optical characterizations including absorption spectra, transmission spectra, photofluorescence spectra, up-conversion spectra, Raman spectra and fluorescence decay lifetime were undertaken on the samples. The results show that not only the fluorescence intensity was strenthened by more than 20 and 70 times, but also the lifetime of Er3+ ions in Al(3+) -doped and K+ and Al(3+) -codoped samples was prolonged to 7.1 and 11.2 ms from 4.8 ms, respecticely. And by analysing the results, the authors concluded that the influences of Al3+ and K+ on Er3+ ions are completely different. And the authors found that Er3+ ions in silica glass may have two up-conversion mechanisms: two-phonon absorption and energy-transfer up-conversion using 980 nm excitation.

[Cooperative luminescence in Yb:YAG crystals].

Cooperative luminescence phenomenon of Yb:YAG crystals was studied. Up-converted blue luminescence was obviously observed in Yb:YAG under excitation in the near-infrared region with a wavelength 940 nm. Experimental evidence was provided by the fact that the intensity of 498 nm luminescence shows a quadratic dependence on excitation power, and the intensity of blue luminescence increased with the increase in Yb ion concentration. It is concluded that this luminescence is due to a cooperative process resulting from a strong interaction of Yb ions. The cooperative luminescence is possiblely assigned to the strong interaction of 4f(13) electrons and neighboring Yb3+ ions in a covalent host lattice such as YAG. Theoretical cooperative luminescence spectrum was calculated.