Influence of Zn-substitution on structural, magnetic, dielectric, and electric properties of Li-Ni-Cu ferrites.

The polycrystalline LiNiZnCuFeO ferrites are fabricated by the method of conventional solid-state reaction technique. The X-ray diffraction (XRD) confirms that the structure of the composition is a single-phase cubic spinel structure for all samples. The particle size of the compositions is varied from 36 to 52 nm.

Investigating the mediating role of online learning motivation in the COVID-19 pandemic situation in Bangladesh.

The purpose of this paper is to investigate the mediating role of online learning motivation (OLM) in the COVID-19 pandemic situation in Bangladesh by observing and comparing direct lectures (DL), instructor-learner interaction (ILI), learner-learner interaction (LLI), and internet self-efficacy (ISE) as predictors of OLM and online learning satisfaction (OLS). Data were collected from 442 undergraduate and graduate students from more than 35 universities in Bangladesh. To test the hypotheses, the PLS-SEM approach was applied using SmartPLS 3.

High-Performance ZnPc Thin Film-Based Photosensitive Organic Field-Effect Transistors: Influence of Multilayer Dielectric Systems and Thin Film Growth Structure.

The key impact and significance of a multilayer polymer-based dielectric system on the remarkable photoresponse properties of zinc phthalocyanine (ZnPc)-based photosensitive organic field-effect transistors (PS-OFETs) have been systematically analyzed at various incident optical powers. A combination of inorganic aluminum oxide (AlO) and organic nonpolar poly(methyl methacrylate) (PMMA) is used as the bilayer dielectric configuration, whereas in the trilayer dielectric system, a bilayer polymer dielectric, consisting of PMMA, as the low- dielectric polymer, on top of poly(vinyl alcohol) (PVA), the high- polar dielectric, has been fabricated along with AlO as the third layer. Before fabricating the OFETs, a systematic optimization of the nature of growth of the ZnPc molecules, deposited on PMMA-coated glass substrates at different substrate temperatures ( ) was performed and examined by atomic-force microscopy, field-emission scanning electron microscopy, X-ray diffraction, and Raman analysis.

White polymer light emitting diodes based on PVK: the effect of the electron injection barrier on transport properties, electroluminescence and controlling the electroplex formation.

The effects of the electron injection barrier on the charge transport, brightness and the electroluminescence (EL) properties of polymer light emitting diodes (PLEDs) with poly(9-vinylcarbazole) (PVK) as an emissive layer have been studied. By using Al and LiF/Al as the cathode in single layer PLEDs and diverse electron transporting layers (ETLs) such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (BPhen) and 2,2',2''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) in the case of multilayer PLEDs, the charge transport, brightness, color tuning and the EL properties of the devices were drastically modified. The energy barrier for electrons affects the electron current flowing through the device, thereby affecting the operating voltage and the brightness of the PLEDs.

Photosensitive organic field effect transistors: the influence of ZnPc morphology and bilayer dielectrics for achieving a low operating voltage and low bias stress effect.

Photosensitive-organic field effect transistors (PS-OFETs) based on a morphology controlled zinc phthalocyanine (ZnPc) layer, with an inorganic-organic bilayer gate dielectric system, fabricated on a glass substrate showed remarkable efficiency as light sensors at various incident optical powers. The indium tin oxide (ITO) and Si/SiO free low-cost OFET devices show low bias stress and a reduced operating voltage with aluminum oxide and poly(methyl methacrylate) (AlO/PMMA) as bilayer gate dielectrics and copper (Cu) as a top contact. They exhibit excellent p-channel behavior with a remarkable photo-responsivity of 2679.

The effect of inorganic/organic dual dielectric layers on the morphology and performance of n-channel OFETs.

The optimization of dual dielectric layers by incorporating poly(vinyl alcohol) (PVA), poly(methyl methacrylate) (PMMA), polystyrene (PS) or poly(4-vinylphenol) (PVP) in combination with Al2O3 resulted in immensely improved OFET characteristics with N,N'-bis(cyclohexyl)naphthalene diimide (NDI-CY2) as the active material. The influence of the polymer dielectric layer on the growth morphology of NDI-CY2 and the structural characterization were investigated using atomic force microscopy (AFM) and thin film XRD analysis. The bottom-gate top-contact OFET devices fabricated on glass substrates with Al contact electrodes demonstrated excellent n-channel behavior in the presence of the Al2O3/PVA dual dielectric with the highest electron mobility (μe) value of 0.

Effect of Dual Cathode Buffer Layer on the Charge Carrier Dynamics of rrP3HT:PCBM Based Bulk Heterojunction Solar Cell.

In bulk heterojunction (BHJ) solar cells, the buffer layer plays a vital role in enhancing the power conversion efficiency (PCE) by improving the charge carrier dynamics. A comprehensive understanding of the contacts is especially essential in order to optimize the performance of organic solar cells (OSCs). Although there are several fundamental reports on this subject, a proper correlation of the physical processes with experimental evidence at the photoactive layer and contact materials is essential.

Efficient blue and white polymer light emitting diodes based on a well charge balanced, core modified polyfluorene derivative.

Fabrication of efficient blue and white polymer light-emitting diodes (PLEDs) using a well charge balanced, core modified polyfluorene derivative, poly[2,7-(9,9'-dioctylfluorene)-co-N-phenyl-1,8-naphthalimide (99:01)] (PFONPN01), is presented. The excellent film forming properties as observed from the morphological study and the enhanced electron transport properties due to the inclusion of the NPN unit in the PFO main chain resulted in improved device properties. Bright blue light was observed from single layer PLEDs with PFONPN01 as an emissive layer (EML) as well as from double layer PLEDs using tris-(8-hydroxyquinoline) aluminum (Alq3) as an electron transporting layer (ETL) and LiF/Al as a cathode.

High-performance n-channel organic thin-film transistor based on naphthalene diimide.

A conjugated molecule comprising 1,4,5,8-naphthalene diimide (NDI) substituted with two octadecylamine (OD) chains has been synthesized (NDI-OD2) in a single step from commercial materials, and its organic thin-film transistor (OTFT) devices on glass substrate have been studied using poly(vinyl alcohol) (PVA) gate dielectric material. Although we utilized the PVA dielectric without any intermediate buffer layer or PVA cross-linkers, excellent electron mobility as high as ∼1.0 cm(2)V(-1) s(-1) are obtained.