TCNQ-based metal organic semiconducting hybrids as phototunable catalyst

The ever-increasing demand to harvest solar light more efficiently has pushed the boundaries of research to develop new materials with superior light absorption properties. Considering that UV irradiation contributes to only 3% of the solar irradiation falling on the earth surface, conventional oxides such as TiO2 (band gap energy of 3.2 eV) absorb <5% of the solar spectrum. This suggests that traditional inorganic semiconductors may require transformational modifications to be suitable for practical applications. This outlines the need fabricate new catalysts with broad absorption capabilities across the UV–Vis–IR range of the solar spectrum. Additionally, easy fabrication and improving the availability of catalytically active sites would also enable rapid translation of such catalysts. For developing such catalysts, appropriate selection of semiconductors is required wherein the bandgap, chemical stability and light absorbing capabilities of each of these semiconductors and/ or metals is essential. The formation of junctions between two semiconductors or a semiconductor/metal has shown tremendous effect in influencing the photocatalytic activities of the semiconductors. In this regard, the current thesis outlines the fabrication of an organic charge transfer complex based on TCNQ using a simple and facile solution based approach. Combining these materials with either metals or other semiconductors improved their charge transfer properties leading to excellent catalysts. Growing such materials directly on high surface area cotton templates further allowed me to control the population of the junction

La Relación Entre la Motivación Docente y Variables de la Organización: Revisión de la Literatura

Abstract Teacher motivation plays a central role in education because ofitsimpacton student motivation. Previous reviews of teacher motivation have focused on individual variables and psychopathology indicators. However, it is also important to understand the effect of organizational variableson teacher motivationbecause these highlightthe contextthat the teacher is a part of(i.e.,the school). The literature review in this paper analysed studies related to teacher motivation and a pre-defined group of organizational variablesthat werepublished between 1990 and 2014 in several electronic databases.The study found that organizational culture was the most studied variable associated with teacher motivationand most studies in this area were published between 2010 and 2014.Further,there was a prevalence of quantitative studies. This paper concludes with the theoreticaland practical implications of the results,as well assuggestions for future research directions

The study of effective factors on the teachers’ work commitment in High Schools

AbstractThe purpose of present study is to investigate effective factors on teachers’ work commitment. The population of this study includes 2800 teachers’ High Schools of 4th region of Tehran city. The samples were chosen by the use of Morgan table and it comprised about 340 subjects. Research method was descriptive. Sampling method was simple random. Gathered data were analyzed by using of descriptive and inferential statistics include Spearman correlation Test. There was positive and significant correlation between economic factors, human relationship, teacher's knowledge, in-school factors, values system, teacher's personality traits and teachers’ work commitment

The Study of Relation Between Emotional Intelligence and Students’ Academic Achievement of High Schools in Tehran City

AbstractThe purpose of present study is to investigate the relations between components of emotional intelligence and students’ academic achievement of High schools in Tehran city .The research method was descriptive .The samples included about 380 subjects,180 girls and 200 boys students. Collected data were analyzed by using of T- student Test and Pearson Correlation.Results showed that there is significant correlation between main components of emotional intelligence including self-motivation, self-awareness, self-regulation, social consciousness, social skills and students’ academic achievement. Also there is meaningful difference between male and female students’ emotional intelligence

Factors and Indicators of Creating Happiness in High School Academic Environment

This study aimed to identify the factors and indicators of happiness in high school educational environments using a qualitative research method. The study population included experts in education and psychology, especially happiness. In addition, the research sample consisted of 21 experts who were selected by purposive and snowball sampling techniques. Semi-structured interviews were applied to collect the required data. In this research, first, factors, components, and indicators were identified based on theoretical and research literature and interviews with experts, and then the experts were graded based on a 10-point Likert-type scale in terms of importance. Finally, the data were analyzed using MAXQDA software. The findings revealed that according to the interviewees, creating happiness in the educational environments of secondary schools depends on five factors, 14 components, and 59 indicators. These factors and indicators included physical space (visual space, facilities, and space design) and educational (cultural-artistic) activities (exciting situations and holding extracurricular workshops). Further, the other factors were academic activities (job skills and personal characteristics of school staff, quality of academic contents, and scientific-research activities), student characteristics (moral-social, emotional-psychological, physical, and family characteristics), and school earnings (formal and informal financial contributions). The respondents believed that these factors affect happiness in secondary schools. In general, the findings of the present study can be used in designing interventions to improve the level of happiness in high schools

Emerging applications of metal-TCNQ based organic semiconductor charge transfer complexes for catalysis

7,7,8,8-tetracyanoquinodimethane (TCNQ), a strong electron withdrawing olefin, has long been regarded as an ideal compound for the synthesis of semiconducting coordination polymers when coordinated to transition metals. Given that TCNQ is an extremely good electron acceptor, transition metals such as Cu, Ag, Mn, Fe, Co, Ni, Zn and Cd have been surveyed for the synthesis of a variety of metal-TCNQ (MTCNQ) compounds. While each of these metal-organic charge transfer complexes show unique physico-chemical properties, these materials have been primarily investigated for electronics applications. More recently, the applicability of TCNQ class of nanomaterials has emerged in other important areas including catalysis, sensing and biology. In this review, the emerging applicability of MTCNQ complexes for catalysis is discussed. In particular, the fabrication of MTCNQ-based materials where M = Cu or Ag is surveyed, followed by discussion on improving their electron-hole recombination properties through a simple galvanic replacement reaction. The mechanistic aspect during the fabrication of these materials with an emphasis on their applicability in catalysis is outlined

The Effect of Deposition Parameters on the Structure and Mechanical Properties of Chromium Oxide Coatings Deposited by Reactive Magnetron Sputtering

Appropriate conditions for depositing hard Cr2O3 coatings by reactive sputtering techniques have yet to be defined. To fill this gap, the effect of principal deposition parameters, including deposition pressure, temperature, Cr-target voltage, and Ar/O2 ratio, on both the structure and mechanical properties of chromium oxide coatings was investigated. A relationship between processing, structure, and the mechanical properties of chromium oxide coatings was established. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the morphology, structure, and chemical compositions of the coatings that were prepared. An optical profilometer was employed to measure both the roughness and thickness of the coatings. The hardness and Young’s modulus of the coatings both as-deposited and after annealing conditions were measured by nanoindentation. The results showed that depositing hard Cr2O3 coatings is a highly critical task, requiring special deposition conditions. Cr2O3 coatings with a high hardness of approximately 25 GPa could be achieved at room temperature, at a low pressure of 1.6 × 10−1 Pa, where Cr-target voltage and oxygen content were 260 V and between 15–25 vol % of total gas, respectively. A dense stoichiometric Cr2O3 structure was found to be responsible for the high chromium oxide coating hardness observed

Zinc oxide/ Silver nanoarrays as reusable SERS substrates with controllable 'hot-spots' for highly reproducible molecular sensing

Hypothesis: The reproducible surface enhanced Raman scattering (SERS)-based sensing of an analyte relies on high quality SERS substrates that offer uniformity over large areas. Uniform ZnO nanoarrays are expected to offer an appropriate platform for SERS sensing. Moreover, since ZnO has good photocatalytic properties, controllable decoration of silver nanoparticles on ZnO nanoarrays may offer an additional opportunity to clean up SERS substrates after each sensing event. Experiments: This study employs a facile soft chemical synthesis strategy to fabricate Raman-active and recyclable ZnO/Ag nanorod arrays as reproducible SERS substrates. Arrays of ZnO nanorods were synthesized using hydrothermal method, which was followed by controllable decoration of ZnO with silver nanoparticles (AgNPs) using an electroless plating technique. Findings: The uniform density of SERS-active 'hot-spots' on ZnO nanoarrays could be controlled on a large 1 1 cm2 substrate. These ZnO/Ag nanoarrays showed high reproducibility (0.132 RSD) towards acquiring SERS spectra of rhodamine B (RB) at 30 random locations on a single substrate. The photocatalytic nature of ZnO/Ag semiconductor/metal hybrid endowed these substrates with reusability characteristics. By controlling metal loading on a semiconductor surface, photocatalytic activity and high SERS performance can be integrated within a single package to obtain high quality, reproducible, stable and recyclable SERS substrates