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Organic–inorganic perovskite quantum dot (PQD)–polymer composites are emerging optoelectronic materials with exceptional properties that are promising widespread application in next‐generation electronics. Advances in the utilization of these materials depend on the development of suitable fabrication techniques to create 3D architectures composed of PQD–polymer for sophisticated optoelectronics. This study introduces a straightforward and effective method for producing 3D architectures of PQD‐encapsulated high‐performance composites (PQD‐HPCs) through direct‐ink writing (DIW). This method employs an ink composed of prefabricated PQDs and hydroxypropyl cellulose (HPC) in dichloromethane (DCM). HPC, an appropriate organic‐soluble polymer, exhibits optical transparency in the highly volatile DCM and enables the formulation of a stable, room‐temperature extrudable ink. The architectures, which are printed by adjusting the halide ratios (Cl, Br, and I) for the compositions of CH3NH3PbBr1.5I1.5, CH3NH3PbBr3, and CH3NH3PbBr1.5Cl1.5, exhibit single peak photoluminescence emissions of red (639 nm), green (515 nm), and blue (467 nm). Optimizing the printing parameters of DIW enables the precise fabrication of programmed and complex PQD‐HPC 3D architectures for advanced anti‐counterfeiting and information encryption. This method has the potential to enhance the functionality of modern printed electronic devices significantly. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator is becoming one of the most efficient energy harvesting device among all mechanical energy harvesters. This device consists of dielectric friction layers and metal electrode which generates electrical charges using electrostatic induction effect. There are several factors influencing the performance of this generator which needs to be evaluated prior to experiment. The absence of a universal technique for TENG simulation makes the device design and optimization hard before practical fabrication, which also lengthens the exploration and advancement cycle and hinders the arrival of practical applications. In order to deepen the understanding the core physic behind the working process of this device, this work will provide comparative analysis on different modes of TENG. Systematic investigation on different material combination, effect of material thickness, dielectric constant and impact of surface patterning is evaluated to shortlist the best material combination. COMSOL Multiphysics simulating environment is used to design, model and analyze factor affecting the overall output performance of TENG. The stationary study in this simulator is performed using 2D geometry structure with higher mesh density. During this study short circuit and open circuit condition were applied to observe the behavior of charge and electric potential produced. This observation is analyzed by plotting charge transfer/electric potential against various displacement distances of dielectric friction layers. The ouput is then provided to load ciruitary to measure the maximum output power of the models. Overall, this study provides an excellent understanding and multi-parameter analysis on basic theoretical and simulation modeling of TENG device. [ABSTRACT FROM AUTHOR]

Energy harvesting technologies now play a significant role in the successful deployment of self-powered electronic devices. Researchers are working on small-scale energy generators fabricated with nanomaterials to harvest ambient energy. Triboelectric nanogenerator (TENG) is an efficient method for harvesting mechanical energy and powering battery-less tiny devices for wearable, implantable medical sensing and internet of things (IoT) sensing applications. So far, many fabrication technologies have been discussed in the literature for the fabrication of TENG including traditional micro/nano-fabrication technologies and 3D printing or additive manufacturing technologies. Extrusion-based 3D printing is a reliable approach for developing a fast, economical and controllable TENG device. This article provides a detailed analysis of recently used material combinations, design and structure formation, and output performance of extrusion-based 3D-printed triboelectric nanogenerators (EB-3DP-TENGs). Also, it presents their latest applications, including powering of electronic devices, silent speech recognition, voice print sensing and gait monitoring. Moreover, it discusses the crucial challenges and approaches used to enhance the performance efficiency of EB-3DP-TENGs. Finally, a visionary roadmap for the future development of EB-3DP-TENGs is provided, which will accelerate research and development. [ABSTRACT FROM AUTHOR]

Magnetic graphene composite comprising graphene sheets decorated with magnetite nanoparticles (NPs) is an important material with numerous successful and potential applications in electronics, chemistry, physics, and bio-medicine. The further use of this material relies on the development of an appropriate patterning method for the production of two-dimensional (2D) and three-dimensional (3D) magnetic graphene composite objects. This study presents a simple and effective strategy to fabricate 2D and 3D micropatterns of Fe 3 O 4 functionalized graphene-polymer (FGP) nanocomposite using extrusion-based 3D printing with a highly loaded FGP nanocomposite ink. The ink consisted of Fe 3 O 4 nanoparticles (NPs), graphene microflakes (GMFs), and hydroxypropyl cellulose (HPC), and was stable and suitable for 3D printing of FGP objects. Various FGP 3D microarchitectures, including a grid, honeycomb, pyramid, and square, were successfully printed using the layer-by-layer (LbL) printing approach. The printed objects exhibited a conductivity of ∼580 S m−1 and magnetic property of 15.8 emu g−1. Successful demonstrations of electronic devices such as a magnet-guided car, a magnetic switch, and a 3D grid for electromagnetic interference (EMI) shielding are also described herein. This 3D printing approach was effective for the 2D and 3D patterning of functional nanocomposites and shows promise for advanced printed electronic applications. Image 1 [ABSTRACT FROM AUTHOR]

OBJECTIVE The objective of our study was to evaluate the level of job satisfaction among healthcare consultants belonging to different specialties working in Public and Private Hospitals. DESIGN Cross sectional study PLACE AND DURATION OF STUDY Healthcare consultants in Karachi. SUBJECTS AND METHOD A cross sectional design was employed through a self-administered questionnaire, comprising of socio-demographic assessment and 10 items Warr-Cook- Wall job satisfaction assessment scale along with additional 8 pretested items, measured in 5 points likert scale. It was distributed and collected from a sample of 332 healthcare consultants over a period of 5 weeks between August. 2013 and September, 2013. Non-probable convenient sampling technique was brought into service. Pearson chi-square analysis was implemented. RESULTS 77.7% of healthcare consultants were found satisfied with their work. 87.4% and 68% of consultants working in Private and Public hospitals were found satisfied with their work respectively. Chi square analysis indicated significant relationship between place of practice and job satisfaction at the p-value of 0.000. A high, almost equal level of job satisfaction was found among consultants belonging to the specialties namely Medicine & allied, Surgery & allied and Diagnostics & Laboratory. Involvement in recreational activities was found to have an impact on job satisfaction. Conclusion: Most of the consultants we re found satisfied with their job. Consultants working in public hospitals were found less satisfied than that of private practitioners, mostly dissatisfied in physical working environment, amount of responsibility at work, rate of income and relationship with the patients. [ABSTRACT FROM AUTHOR]

3D printed electronics employing direct‐ink‐writing methods are promising alternative manufacturing technologies for realizing structural electronics. The emerging demand for accessible, cost‐effective, and rapid writing calls for novel approaches to print functional components onto nonflat and 3D architectures. This study presents a novel air‐pressure‐assisted pen‐nib printing approach producing electrical and functional components with various material inks on flat and 3D surfaces. Based on the inks' rheological properties, the ejected ink's quantity through the nib is manipulated via air pressure; thus, the printed line width is controlled. This strategy also achieves the viscosity range extension of printable inks by enabling printing inks that cannot be used in general pen‐based printing. Three functional inks with different rheological properties—Ag catalyst ink for Cu electroless deposition, Ag‐PEDOT:PSS ink, and thermochromic pigment inks are designed. Several electrical and functional components, such as highly conductive Cu interconnects, Cu spiral coils for wireless power transfer receivers, flexible heaters, and matrix data codes based on temperature‐responsive color transitions are demonstrated. Furthermore, parallel printing with a multi‐nib print‐head is demonstrated for improving the printing speed and manufacturing scalability. The authors believe that this novel approach is promising as a manufacturing technique for realizing 3D printed electronics. [ABSTRACT FROM AUTHOR]

An effective approach is required to improve the spatial resolution and electrical conductivity of printed graphene patterns for advanced graphene-based printed electronics. Here, we describe a simple and effective strategy to fabricate few-micrometer-wide graphene patterns by meniscus-guided printing, using a highly concentrated graphene oxide (GO, 2 wt%) ink. Our approach exploits the rapid solidification of an ink meniscus formed by horizontal pulling of a micronozzle. To achieve uniform printing with continuous flow of the highly concentrated GO ink through the nozzle, polyvinylpyrrolidone (PVP), which acts as a gelation inhibitor and rheology modifier, was added to the aqueous GO solution. GO reduction and PVP removal from the printed patterns was achieved simultaneously, by thermal treatment. Electrical conductivities and widths of the reduced GO (rGO) patterns could be easily modulated by adjusting the nozzle-pulling rate and changing the nozzle-opening size, respectively. Toward applications in electronics, successful fabrication of a field-effect transistor based on a printed rGO channel is also described. This approach can be effective for high-resolution printing of graphene patterns for electronic applications. [ABSTRACT FROM AUTHOR]