diode

The performance of blue quantum dot light-emitting diodes (QLEDs) is limited by unbalanced charge injection, resulting from insufficient holes caused by low mobility or significant energy barriers. Here, we introduce an angular-shaped heteroarene based on cyclopentane[ b ]thiopyran (C8 -SS) to modify the hole transport layer poly- N -vinylcarbazole (PVK), in blue QLEDs. C8 -SS exhibits high hole mobility and conductivity due to the π···π and S···π interactions...

Organic semiconductors find widespread applications in the realm of organic light-emitting diodes (OLEDs) as well as organic photovoltaic cells. In the domain of OLED devices, it is plausible for nano-based Mg metal complexes to play a role as electron and hole-transport layers. In the present investigation, we synthesized 2(2-methyl 8-hydroxyquinoline) magnesium [Mg(mq)2 ] nanorods through the employment of the precipitation method, using 2-methyl 8- hydroxyquinoline and magnesium acetate. We employed various techniques to characterize the Mg(mq)2 nanorods, including powder XRD, FTIR spectroscopy, SEM, EDX, UV-Vis, and PL spectroscopy studies...

Electrochemistry-based light-emitting devices have gained considerable attention in different applications such as sensing and optical imaging. In particular, such systems are an interesting alternative for the development of multimodal light-emitting platforms. Herein we designed a multicolor light-emitting array, based on the electrochemical switch-on of light-emitting diodes (LEDs) with a different intrinsic threshold voltage. Thermodynamically and kinetically favored coupled redox reactions, i.e. the oxidation of Mg and the reduction of protons on Pt, act as driving force to power the diodes...

Boron carbonitride (BCN) films containing hybridized bonds involving B, C, and N over wide compositional ranges enable an abundant variety of new materials, properties, and applications; however, their electronic performance is still limited by the presence of structural and electronic defects, yielding sluggish mobility and electrical conductivity. This work reports on mechanically stable BCN films and their corresponding optical and electronic properties. The ternary BCN films consisting of hybridized B-C-N bonds have been achieved by varying N2 flow by the radio frequency magnetron sputtering method...

The prevalence of male infertility has become a significant clinical concern worldwide, with a noticeable upward trend in recent times. The rates of fertilization and subsequent development of embryos are dependent on many parameters associated with the quality and viability of sperm. Photobiomodulation (PBM) is a promising approach with a great potential for translational applications in the treatment of spermatozoa exhibiting low quality and motility. In this study, a comprehensive analysis of the existing literature, specifically examining the mechanisms of action of PBM has been presented...

The propagation of spin waves is one of the promising ways to design nanoscale spintronic devices. The spin waves can interact with the magnetic skyrmion, a particle-like object that is topologically stabilized by Dzyaloshinskii-Moriya interaction (DMI) in thin film heterostructures. In this work, a spin wave-driven skyrmion-based diode is proposed by employing a T-shaped ferromagnetic nanotrack. The one-way motion of the skyrmion is achieved by exploiting the mid-arm at the center of the nanotrack. This prevents the reverse motion of the skyrmion owing to the skyrmion Hall effect (SkHE) and the absence of a repulsive force from the far edge in the mid-arm region...

The field of biofabrication imposes stringent requirements on the polymerization activity and biosafety of photopolymeric hydrogel systems. In this investigation, we designed and synthesized four hemicyanine dyes with a D-π-A structure specifically tailored for biofabrication purposes. These novel dyes, incorporating carbazole (CZ), triphenylamine (TPA), anthracene (AN), and benzodithiophene (BDT) as electron donors, along with heterocyclic salt (IN) as electron acceptors, were prepared using a straightforward synthesis method...

Nickel stands out as one of the prevalent heavy metal ionic pollutants found in water. It is urgent to devise a simple, efficient, budget-friendly, highly-selective and proficient method for detecting Ni(II). This work reports an approach to design a nanofluidic diode for the ultrasensitive and label-free detection of nickel ions based on layer-by-layer assembly of polyarginine (PA) and polyglutamic acid (γ-PGA) on the inner surface of asymmetric nanochannels. We can tune the adsorption/desorption characteristics of the asymmetric nanochannels for Ni2+ by adjusting the pH changes, i...

Quasi-2D perovskites have emerged as highly promising materials for application in perovskite light-emitting diodes (PeLEDs), garnering significant attention due to their outstanding semiconductor properties. These materials boast an inherent multi-quantum well structure that imparts a robust confinement effect, particularly advantageous for blue emission. However, the development of blue emitters utilizing quasi-2D perovskites encounters challenges, notably colour instability, multipeak emission, and suboptimal fluorescence yield...

The bioaccessibility and bioavailability of phenolic compounds (PC) influence directly their role in disease prevention/control. Studies have evaluated this ability through complex plant and food matrices, which may reflect more a synergistic effect of the matrix than the ability of the PCs, hindering their individual exploitation in nutraceutical or pharmaceutical applications. In the present study ten pure PCs representing major classes were evaluated for their bioaccessibility and intestinal absorption in an in vitro simulated gastrointestinal digestion (SGD)...

Conical nanochannels employed to create ionic current rectification (ICR) in nanofluidic devices are prone to clogging due to the contraction at one end. As an alternative approach for creating ICR, a cylindrical nanochannel covered with a polyelectrolyte layer (PEL) of variable thickness is proposed in the present study. The efficacy of the proposed design is studied by numerically solving the governing equations including the Poisson, Nernst-Planck, and Stokes-Brinkman equations. Furthermore, the fundamental mechanism behind ICR is explained using a simplified one-dimensional model...

The "cyan gap" is the bottleneck problem in violet-driven full-spectrum white-light-emitting diodes (wLEDs) in healthy lighting. Accordingly, we develop a novel broadband-blue-cyan emission Na3 KMg7 (PO4 )6- x (BO3 ) x :Eu2+ (NKMPB:Eu2+ ) phosphor via crystal-site engineering. This phosphor is derived from the Na3 KMg7 (PO4 )6 :Eu2+ phosphor, which shows desired abundant cyan emissive components. A comparative study is conducted to reveal the microstructure-property relationship and the key influential factors to its spectrum distribution...

Heavy-metal-free III-V colloidal quantum dots (QDs) exhibit promising attributes for application in optoelectronics. Among them, InAs QDs are demonstrating excellent optical performance with respect to absorption and emission in the near-infrared spectral domain. Recently, InAs QDs attained a substantial improvement in photoluminescence quantum yield, achieving 70% at a wavelength of 900 nm through the strategic overgrowth of a thick ZnSe shell atop the InAs core. In the present study, light-emitting diodes (LEDs) based on this type of InAs/ZnSe QDs are fabricated, reaching an external quantum efficiency (EQE) of 13...

Photoacoustic (PA) imaging is hybrid imaging modality with good optical contrast and spatial resolution. Portable, cost-effective, smaller footprint light emitting diodes (LEDs) are rapidly becoming important PA optical sources. However, the key challenge faced by the LED-based systems is the low light fluence that is generally compensated by high frame averaging, consequently reducing acquisition frame-rate. In this study, we present a simple deep learning U-Net framework that enhances the signal-to-noise ratio (SNR) and contrast of PA image obtained by averaging low number of frames...

BACKGROUND: African giant pouched rats, trained by Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling (APOPO), have demonstrated their ability to detect tuberculosis (TB) from sputum. We assessed rat-based case detection and compared the mycobacterium bacillary load (MTB-load) in children versus adults. METHODS: From January-December 2022, samples were collected prospectively from 69 Directly Observed Therapy (DOT) facilities' presumed TB patients. Using an average of five rats, APOPO re-evaluated patients with bacteriologically negative (sputum-smear microscopy or Xpert MTB/RIF) results...

In recent years, the visible light positioning field has experienced remarkable advancements. However, smartphones find it difficult to identify light-emitting diode (LED) and extract each LED's light signal intensity due to the low-frequency and uneven sampling of built-in ambient light sensors (ALS, which is a photodiode that measures ambient light in lux units). Thus, traditional visible light positioning systems cannot be directly applied to smartphones. In this Letter, we propose a single-light visible light positioning system using a non-modulated LED as an emitter, the built-in ALS as the receiver, and the inertial measurement unit of the smartphone to assist in measuring the smartphone's attitude...

A Tm:LiYF4 laser operating on the 3 H4  → 3 H5 transition is embedded in a high-power diode-pumped Nd:ASL laser for intracavity upconversion pumping at 1.05 µm. This leads to a record-high output power at 2.3 µm for any bulk thulium laser pumped by an upconversion process. The continuous-wave Tm:LiYF4 laser delivers 1.81 W at 2.3 µm for 32 W of laser-diode pump power, making this kind of pumping competitive with direct diode pumping. The intracavity pumping process allows for counteracting the low absorption inherent to upconversion pumping and to dispatch the thermal loads on two separate laser crystals...

Here, we propose a sandwich-like Si-doping scheme (undoped/Si-doped/undoped) in Al0.6 Ga0.4 N quantum barriers (QBs) to simultaneously promote the optoelectronic performances and reliability of deep ultraviolet light-emitting diodes (DUV-LEDs). Through experimental and numerical analyses, in the case of DUV-LEDs with conventional uniform Si-doping QB structure, severe operation-induced reliability degradation, including the increase of reverse leakage current (IR) and reduction of light output power (LOP), will offset the enhancement of optoelectronic performances as the Si-doping levels increase to an extent, which hinders further development of DUV-LEDs...

A method by detecting the ellipse fitting degree of the trajectory equation formed by two self-mixing (SM) signals in the multi-longitudinal mode laser SM system with a Wollaston prism is presented to test the free spectral range (FSR) of the laser. By utilizing the orthogonal vector and phase-shift characteristics between adjacent longitudinal modes, the fluctuations in multi-mode SM effects caused by changes in the external cavity length are transformed into alterations in the trajectory composed of two orthogonal SM signals...

Low phase noise and narrow linewidth lasers are achieved by implementing self-injection locking of a DFB laser on two distinct fiber Fabry-Perot resonators. More than 45 dB improvement of the laser phase or frequency noise is observed when the laser is locked. In both cases, a frequency noise floor below 1 Hz2 /Hz is measured. The integrated linewidth of the best of the two lasers is computed to be in the range of 400 Hz and appears to be dominated by vibration noise close to the carrier...