Atto-Scale Noise Near-Infrared Organic Photodetectors Enabled by Controlling Interfacial Energetic Offset through Enhanced Anchoring Ability.

The near-infrared (NIR) sensor technology is crucial for various applications such as autonomous driving and biometric tracking. Silicon photodetectors (SiPDs) are widely used in NIR applications; however, their scalability is limited by their crystalline properties. Organic photodetectors (OPDs) have attracted attention for NIR applications owing to their scalability, low-temperature processing, and notably low dark current density (JD), which is similar to that of SiPDs. However, the still high JD (at NIR band) and few measurements of noise equivalent powers (NEPs) pose challenges for accurate performance comparisons. This study addresses these issues by quantitatively characterizing the performance matrix and JD generation mechanism using electron-blocking layers (EBLs) in OPDs. The energy offset at an EBL/photosensitive layer interface determines the thermal activation energy and directly affects JD. A newly synthesized EBL (3PAFBr) substantially enhances the interfacial energy barrier by forming a homogeneous contact owing to the improved anchoring ability of 3PAFBr. As a result, the OPD with 3PAFBr yields a noise current of 852 aA (JD = 12.3 fA cm⁻2 at V → -0.1 V) and several femtowatt-scale NEPs. As far as it is known, this is an ultralow of JD in NIR OPDs. This emphasizes the necessity for quantitative performance characterization.

Self-Powering Sensory Device with Multi-Spectrum Image Realization for Smart Indoor Environments.

The development of organic-based optoelectronic technologies for the indoor Internet of Things market, which relies on ambient energy sources, has increased, with organic photovoltaics (OPVs) and photodetectors (OPDs) considered promising candidates for sustainable indoor electronic devices. However, the manufacturing processes of standalone OPVs and OPDs can be complex and costly, resulting in high production costs and limited scalability, thus limiting their use in a wide range of indoor applications. This study uses a multi-component photoactive structure to develop a self-powering dual-functional sensory device with effective energy harvesting and sensing capabilities. The optimized device demonstrates improved free-charge generation yield by quantifying charge carrier dynamics, with a high output power density of over 81 and 76 µW cm-2 for rigid and flexible OPVs under indoor conditions (LED 1000 lx (5200 K)). Furthermore, a single-pixel image sensor is demonstrated as a feasible prototype for practical indoor operating in commercial settings by leveraging the excellent OPD performance with a linear dynamic range of over 130 dB in photovoltaic mode (no external bias). This apparatus with high-performance OPV-OPD characteristics provides a roadmap for further exploration of the potential, which can lead to synergistic effects for practical multifunctional applications in the real world by their mutual relevance.

Ultra-Low Noise Level Infrared Quantum Dot Photodiodes with Self-Screenable Polymeric Optical Window.

Quantum dot photodiodes (QPDs) have garnered significant attention because of their unparalleled near-infrared (NIR) detection capabilities, primarily attributable to their size-dependent bandgap tunability. Nevertheless, the broadband absorption spectrum of QPD engenders substantial noise floor within superfluous visible light regions, notably hindering their use in several emerging applications necessitating the detection of faint micro-light signals. To overcome these hurdles, a self-screenable NIR QPD featuring an internal optical filter with a thick polymeric interlayer to reduce electronic noise is demonstrated. This effectively screens out undesirable visible light regions while reducing the ionized defect owing to decreased density of state, yielding an extremely low dark current (≈1010 A cm-2 at V = -1 V). Consequently, the electronic noise spectral density is attained at levels below ≈10-27 -10-28 A2 Hz-1 , and responsivity (R) dropped to 92% within the visible light spectrum.

A Tunable and Wearable Dual-Band Metamaterial Absorber Based on Polyethylene Terephthalate (PET) Substrate for Sensing Applications.

Advanced wireless communication technology claims miniaturized, reconfigurable, highly efficient, and flexible meta-devices for various applications, including conformal implementation, flexible antennas, wearable sensors, etc. Therefore, bearing these challenges in mind, a dual-band flexible metamaterial absorber (MMA) with frequency-reconfigurable characteristics is developed in this research. The geometry of the proposed MMA comprises a square patch surrounded by a square ring, which is mounted over a copper-backed flexible dielectric substrate. The top surface of the MMA is made of silver nanoparticle ink and a middle polyethylene terephthalate (PET) substrate backed by a copper groundsheet. The proposed MMA shows an absorption rate of above 99% at 24 and 35 GHz. In addition, the absorption features are also studied for different oblique incident angles, and it is found that the proposed MMA remains stable for θ = 10-50°. The frequency tunability characteristics are achieved by stimulating the capacitance of the varactor diode, which connects the inner patch with the outer ring. To justify the robustness and conformability of the presented MMA, the absorption features are also studied by bending the MMA over different radii of an arbitrary cylinder. Moreover, a multiple-reflection interference model is developed to justify the simulated and calculated absorption of the proposed MMA. It is found that the simulated and calculated results are in close agreement with each other. This kind of MMA could be useful for dual-band sensing and filtering operations.

Nickel-Based High-Bandwidth Nanostructured Metamaterial Absorber for Visible and Infrared Spectrum.

The efficient control of optical light at the nanoscale level attracts marvelous applications, including thermal imaging, energy harvesting, thermal photovoltaics, etc. These applications demand a high-bandwidth, thermally robust, angularly stable, and miniaturized absorber, which is a key challenge to be addressed. So, in this study, the simple and cost-effective solution to attain a high-bandwidth nanostructured absorber is demonstrated. The designed nanoscale absorber is composed of a simple and plain circular ring of nickel metal, which possesses many interesting features, including a miniaturized geometry, easily fabricable design, large operational bandwidth, and polarization insensitivity, over the previously presented absorbers. The proposed nanoscale absorber manifests an average absorption of 93% over a broad optical window from 400 to 2800 nm. Moreover, the detailed analysis of the absorption characteristics is also performed by exciting the optical light's various incident and polarization angles. From the examined outcome, it is concluded that the nanostructured absorber maintains its average absorption of 80% at oblique incident angles in a broad wavelength range from 400 to 2800 nm. Owing to its appealing functionalities, such as the large bandwidth, simple geometry, low cost, polarization insensitivity, and thermal robustness of the constituting metal, nickel (Ni), this nano-absorber is made as an alternative for the applications of energy harvesting, thermal photovoltaics, and emission.

Revisiting the Classical Wide-Bandgap HOMO and Random Copolymers for Indoor Artificial Light Photovoltaics.

Organic indoor photovoltaics (IPVs) are attractive energy harvesting devices for low-power consumption electronic devices and the Internet of Things (IoTs) owing to their properties such as being lightweight, semitransparent, having multicoloring capability, and flexibility. It is important to match the absorption range of photoactive materials with the emission spectra of indoor light sources that have a visible range of 400-700 nm for IPVs to provide sustainable, high-power density. To this end, benzo[1,2-b:4,5-b']dithiophene-based homopolymer (PBDTT) is synthesized as a polymer donor, which is a classical material that has a wide bandgap with a deep highest occupied molecular orbitals (HOMO) level, and a series of random copolymers by incorporating thieno[3,4-c]pyrrole-4,6,-dione (TPD) as a weak electron acceptor unit in PBDTT. The composition of the TPD unit is varied to fine tune the absorption range of the polymers; the polymer containing 70% TPD (B30T70) perfectly covers the entire range of indoor lamps such as light-emitting diodes (LEDs) and fluorescent lamp (FL). Consequently, B30T70 shows a dramatic enhancement of the power conversion efficiency (PCE) from 1-sun (PCE: 6.0%) to the indoor environment (PCE: 18.3%) when fabricating organic IPVs by blending with PC71 BM. The simple, easy molecular design guidelines are suggested to develop photoactive materials for efficient organic IPVs.

2D MXene: A Potential Candidate for Photovoltaic Cells? A Critical Review.

The 2D transition metal carbides/nitrides (2D MXenes) are a versatile class of 2D materials for photovoltaic (PV) systems. The numerous advantages of MXenes, including their excellent metallic conductivity, high optical transmittance, solution processability, tunable work-function, and hydrophilicity, make them suitable for deployment in PV technology. This comprehensive review focuses on the synthesis methodologies and properties of MXenes and MXene-based materials for PV systems. Titanium carbide MXene (Ti3 C2 Tx ), a well-known member of the MXene family, has been studied in many PV applications. Herein, the effectiveness of Ti3 C2 Tx as an additive in different types of PV cells, and the synergetic impact of Ti3 C2 Tx as an interfacial material on the photovoltaic performance of PV cells, are systematically examined. Subsequently, the utilization of Ti3 C2 Tx as a transparent conductive electrode, and its influence on the stability of the PV cells, are discussed. This review also considers problems that emerged from previous studies, and provides guidelines for the further exploration of Ti3 C2 Tx and other members of the 2D MXene family in PV technology. This timely study is expected to provide comprehensive understanding of the current status of MXenes, and to set the direction for the future development in 2D material design and processing for PVs.

Energy recycling under ambient illumination for internet-of-things using metal/oxide/metal-based colorful organic photovoltaics.

Colorful indoor organic photovoltaics (OPVs) have attracted considerable attention in recent years for their autonomous function in internet-of-things (IoT) devices. In this study, a solution-processed TiO2layer in a metal-oxide-metal (MOM) color filter electrode is used for light energy recycling in P3HT:ICBA-based indoor OPVs. The MOM electrode allows for tuning of the optical cavity mode to maximize photocurrent production by modulating the thickness of the TiO2layer in the sandwich structure. This approach preserves the OPVs' optoelectronic properties without damaging the photoactive layer and enables them to display a suitable range of vivid colors. The optimized MOM-OPVs demonstrated an excellent power conversion efficiency (PCE) of 8.8% ± 0.2%, which is approximately 20% higher than that of reference opaque OPVs under 1000 lx light emitting diode illumination. This can be attributed to the high photocurrent density due to the nonresonant light reflected from metals into the photoactive layer. Additionally, the proposed MOM-OPVs exhibited high external quantum efficiency and large parasitic shunt resistances, leading to improved fill factor and PCE values. Thus, the study's MOM electrode provides excellent feasibility for realizing colorful and efficient indoor OPVs for IoT applications.

A Case of Extracorporeal Membrane Oxygenation as a Salvage Therapy for COVID-19-Associated Severe Acute Respiratory Distress Syndrome: Mounting Evidence.

Coronavirus disease 2019 (COVID-19) caused by a novel human coronavirus has led to a tsunami of viral illness across the globe, originating from Wuhan, China. Although the value and effectiveness of extracorporeal membrane oxygenation (ECMO) in severe respiratory illness from COVID-19 remains unclear at this time, there is emerging evidence suggesting that it could be utilized as an ultimate treatment in appropriately selected patients not responding to conventional care. We present a case of a 32-year-old COVID-19 positive male with a history of diabetes mellitus who was intubated for severe acute respiratory distress syndrome (ARDS). The patient's hypoxemia failed to improve despite positive pressure ventilation, prone positioning, and use of neuromuscular blockade for ventilator asynchrony. He was evaluated by a multidisciplinary team for considering ECMO for refractory ARDS. He was initiated on venovenous ECMO via dual-site cannulation performed at the bedside. Although his ECMO course was complicated by bleeding, he showed a remarkable improvement in his lung function. ECMO was successfully decannulated after 17 days of initiation. The patient was discharged home after 47 days of hospitalization without any supplemental oxygen and was able to undergo active physical rehabilitation. A multidisciplinary approach is imperative in the initiation and management of ECMO in COVID-19 patients with severe ARDS. While ECMO is labor-intensive, using it in the right phenotype and in specialized centers may lead to positive results. Patients who are young, with fewer comorbidities and single organ dysfunction portray a better prognosis for patients in which ECMO is utilized.

A Case of Guillain-Barré Syndrome Associated With COVID-19.

A novel member of human RNA coronavirus, which is an enveloped betacoronavirus, has been termed severe acute respiratory syndrome coronavirus-2 (SARS COV-2). The illness caused by SARS COV-2 is referred to as the coronavirus disease 2019 (COVID-19). It is a highly contagious disease that has resulted in a global pandemic. The clinical spectrum of COVID-19 ranges from asymptomatic illness to acute respiratory distress syndrome, septic shock, multi-organ dysfunction, and death. The most common symptoms include fever, fatigue, dry cough, dyspnea, and diarrhea. Neurological manifestations have also been reported. However, the data on the association of Guillain-Barré syndrome (GBS) with COVID-19 are scarce. We report a rare case of a COVID-19-positive 36-year-old immunocompromised male who presented with clinical features of GBS. His clinical examination showed generalized weakness and hyporeflexia. The cerebrospinal fluid (CSF) analysis showed albuminocytological dissociation. Intravenous immunoglobulin (IVIG) was administered based on the high clinical suspicion of GBS. The patient's neurological condition worsened with progression to bulbar weakness and ultimately neuromuscular respiratory failure requiring mechanical ventilation. His nerve conduction studies were consistent with demyelinating polyneuropathy. He received five plasma exchange treatments and was successfully weaned from mechanical ventilation. A brain and cervical spine magnetic resonance imaging was obtained to rule out other causes, which was normal. COVID-19 is believed to cause a dysregulated immune system, which likely plays an important role in the neuropathogenesis of GBS.

Swyer-James-Macleod Syndrome: Case Report and Brief Literature Review.

Swyer-James-Macleod syndrome is a rare radiologic entity with radiolucent lung fields which could include the entire lung, a lobe or a subsegment. The pathogenesis is unclear but is thought to be related to childhood pulmonary viral and non-viral infections with subsequent vascular and alveolar distortion. It usually presents incidentally in asymptomatic patients on imaging, but could present with recurrent pulmonary infections, shortness of breath, cough, hemoptysis or bronchiectasis. Treatment is usually observation if asymptomatic, but could potentially include inhaled steroids, bronchodilators, lobectomy segmentectomy or pneumonectomy depending on the clinical condition and severity of the symptoms. We present a case of SJMS found in a asymptomatic patient along with a brief literature review.

Tuberculosis treatment failure in AIDS: vengeance with renal and ocular manifestations.

Tuberculosis treatment failure is not uncommon in patients with AIDS. Treatment failure is defined as a positive sputum smear or culture at month 5 or later in the course of the treatment. The clinical presentations in these patients show remarkable heterogeneity. In this report, we chronicle the case of a patient with treatment failure presenting as the disseminated disease, specifically ocular and renal tuberculosis. Additionally, we undertake here a brief literature review highlighting the increased resistance to tuberculosis treatment in patients with AIDS, the rarity of ocular tuberculosis and the importance of tailoring drug regimens on an individual basis in these coinfected patients.

Spontaneous carotid artery dissection: a rare cause of stroke in pregnancy and approach to diagnosis and management.

Acute onset of neurological symptoms in a pregnant female is a rare medical emergency. We report a case of a 38-year-old female who presented with a stroke secondary to carotid artery dissection. Our case illustrates the need to consider vascular imaging before administering thrombolytic therapy in peripartum females to avoid unnecessary risks to either the mother or the fetus. Management is controversial and is discussed briefly.