ABSTRACT
The everlasting pursuit of hybrid organic-inorganic lead-free semiconductors has directed the focus towards eco-friendly copper-based systems, perhaps because of the diversity in chemistry, controlling the structure-property relationship. In this work, we report single crystals of a Cu(i) halide-based perovskite-like organic-inorganic hybrid, (TMA)Cu2Br3, (TMA = tetramethylammonium), consisting of unusual one-dimensional inorganic anionic chains of -(Cu2Br3)-, electrostatically stabilized by organic cations, and the Cu(i)-Cu(i) distance of 2.775 Å indicates the possibility of cuprophilic interactions. X-ray photoelectron spectroscopy measurements further confirmed the presence of exclusive Cu(i) in (TMA)Cu2Br3 and electronic structure calculations based on density functional theory suggested a direct bandgap value of 2.50 eV. The crystal device demonstrated an impressive bulk photovoltaic effect due to the emergence of excitonic Cu(i)-Cu(i) interactions, as was clearly visualized in the charge-density plot as well as in the Raman spectroscopic analysis. The single crystals of a silver analogue, (TMA)Ag2Br3, have also been synthesized revealing a Ag(i)-Ag(i) distance of 3.048 Å (signature of an argentophilic interaction). Unlike (TMA)Cu2Br3, where more density of states from Cu compared to Br near the Fermi level was observed, (TMA)Ag2Br3 exhibited the opposite trend, possibly due to variation in the ionic potential influencing the overall bonding scenario.
ABSTRACT
Two-dimensional (2D) metal-organic frameworks (MOFs) are usually associated with higher electrical conductivity and charge carrier mobility when compared with 3D MOFs. However, attaining metallic conduction in such systems through synthetic or postsynthetic modifications is extremely challenging. Herein, we present the fabrication of thin films of a 2D MOF, Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), decorated with silver nanoparticles (AgNPs) exhibiting significant conductivity enhancement at room temperature. Variable-temperature electrical transport measurements across the low-temperature (200 K) to high-temperature (373 K) regime evidenced metallic conduction. Interestingly, thin films of a 3D MOF, CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane), upon decoration with AgNPs, disclosed a converse trend. The origin of such distinctive observations on AgNPs@Cu3(HHTP)2 and AgNPs@CuTCNQ systems was comprehended by using first-principles density functional theory (DFT) calculations and attributed to an interfacial electronic effect. Our work sheds new light on rationally designing synthetic modifications in thin films of MOFs to tune the electrical transport property.
ABSTRACT
Nurse burnout is a widespread phenomenon characterized by a reduction in nurses' energy that manifests in emotional exhaustion, lack of motivation, and feelings of frustration and may lead to reductions in work efficacy. This study was conducted to assess the level of burnout among Jordanian nurses and to investigate the influence of leader empowering behaviors (LEBs) on nurses' feelings of burnout in an endeavor to improve nursing work outcomes. A cross-sectional and correlational design was used. Leader Empowering Behaviors Scale and the Maslach Burnout Inventory (MBI) were employed to collect data from 407 registered nurses, recruited from 11 hospitals in Jordan. The Jordanian nurses exhibited high levels of burnout as demonstrated by their high scores for Emotional Exhaustion (EE) and Depersonalization (DP) and moderate scores for Personal Accomplishment (PA). Factors related to work conditions, nurses' demographic traits, and LEBs were significantly correlated with the burnout categories. A stepwise regression model-exposed 4 factors predicted EE: hospital type, nurses' work shift, providing autonomy, and fostering participation in decision making. Gender, fostering participation in decision making, and department type were responsible for 5.9% of the DP variance, whereas facilitating goal attainment and nursing experience accounted for 8.3% of the PA variance. This study highlights the importance of the role of nurse leaders in improving work conditions and empowering and motivating nurses to decrease nurses' feelings of burnout, reduce turnover rates, and improve the quality of nursing care.
