Search

In this work, the device modeling of n-i-p architecture based on FTO/WSe2/ CsSn x Ge 1 - x I 3 x = 0.5 /Spiro-OMeTAD/Au was performed using solar cell capacitance simulator-one dimensional (SCAPS-1D) tool. All simulations were performed in the 1.5G AM sunlight spectrum. The effect of various parameters such as defect density, thickness of absorber layer and work function of contact electrode have been investigated. The effect of temperature, series and shunt resistance have also been analyzed. After optimization of photovoltaic parameters, we obtained power conversion efficiency 18.51%, fill factor 79.41%, open circuit voltage (Voc) 0.8458 V and short-circuit current density (Jsc) 27.562 mA/cm2. The modeling of CsSn x Ge 1 - x I 3 x = 0.5 based devices open the door for the fabrication of feasible and highly efficient perovskite solar cells. [ABSTRACT FROM AUTHOR]

This paper sets up a small open new Keynesian economy model with constrained households and incomplete markets to address the driving forces of business cycles in Korea. It shows that there exists a substantial fraction of constrained households who cannot have access to financial market. Furthermore, the estimated model reveals that a TANK model is better than a RANK model in explaining business cycles in Korea. The effect of domestic productivity shock on Korean economy has dominated in the variations of output, while the contribution of the foreign productivity shock to the variations of output and inflation has increased after the Asian financial crisis. The monetary policy shock has dominated the variation of inflation at short and medium horizons. [ABSTRACT FROM AUTHOR]

The molecular design and conformations of hole-transporting materials (HTM) have unravelled a strategy to enhance the performance of environmentally sustainable perovskite solar cells (PSC). Several attempts have been made and several are underway for improving the efficiency of PSCs by designing an efficient HTM, which is crucial to preventing corrosion, facilitating effective hole transportation, and preventing charge recombination. There is a need for a potential alternative to the current market-dominating HTM due to its high cost of production, dopant requirements, moisture sensitivity, and low stability. Among several proposed HTMs, molecules derived from thiophene exhibit unique behaviour, such as the interaction with under-coordinated Pb2+, thereby facilitating the passivation of surface defects in the perovskite layer. In addition, coupling a suitable side chain imparts a hydrophobic character, eventually leading to the development of a moisture-sensitive and highly stable PSC. Furthermore, thiophene-backboned polymers with ionic pendants have been employed as an interfacial layer between PSC layers, with the backbone facilitating efficient charge transfer. This perspective article comprehensively presents the design strategy, characterization, and function of HTMs associated with thiophene-derived molecules. Hence, it is observed that thiophene-formulated HTMs have an enhanced passivation effect, good performance in an open-circuit environment, longevity, humidity resistance, thermostability, good hole extraction, and mobility in a dopant-free condition. For a better understanding, the article provides a comparative description of the activity and function of thiophene-based small molecules and polymers and their effect on device performance. [ABSTRACT FROM AUTHOR]

This paper examines the problem of identifying network anomalies when processing data streams in industrial systems. A network anomaly refers to a malicious signature and the current context: network environment and topology, routing parameters, and node characteristics. As a result of the study, it is proposed to use a neocortex model that supports the memory mechanism to detect network anomalies. [ABSTRACT FROM AUTHOR]

This study considers the problem of detecting network anomalies caused by computer attacks in the networks of the industrial Internet of things. To detect anomalies, a new method is proposed, built using a hierarchical temporal memory (HTM) computation model based on the neocortex model. An experimental study of the developed method of detecting computer attacks based on the HTM model showed the superiority of the developed solution over the LSTM analog. The developed prototype of the anomaly detection system provides continuous training on unlabeled data sets in real time, takes into account the current network context, and applies the accumulated experience by supporting the memory mechanism. [ABSTRACT FROM AUTHOR]

The photovoltaic performances of n-i-p or inverted p-i-n BaSi2 homojunction solar cells are limited by the parasitic high light absorption of n-BaSi2 or p-BaSi2 window layer. In this work, diverse electron transport materials (ETMs) and hole transport materials (HTMs) are employed instead of BaSi2 as window layers to promote the performances of BaSi2 solar cells, and the effects of different ETMs and HTMs were simulated and comprehensively studied. For n-ETM/i-BaSi2/p-BaSi2 solar cells, the solar cell with ZnO exhibits the highest efficiency of 28.21%. As increasing the thicknesses of ETM layer from 5 nm to 100 nm, the efficiency for n-BaSi2/i-BaSi2/p-BaSi2 solar cell decreases seriously from 24.52% to 15.99%, while the solar cells with wide band gap ETMs including SnO2, TiO2 and ZnO show neglectable change in performances. The performances n-ETM/i-BaSi2/p-BaSi2 solar cells are affected by donor like defects more than acceptor like defects in i-BaSi2. For p-HTM/i-BaSi2/n-BaSi2 solar cells, employing Cu2O, CuI, CuSCN or NiO as HTM layer produces evident valence band discrepancies at HTM/i-BaSi2 interfaces. Heavy doping in HTM layer is necessary desired to overcome the energy band barriers. As increasing the thicknesses of HTM layer from 5 nm to 100 nm, the efficiency for p-BaSi2/i-BaSi2/n-BaSi2 solar cell also decreases from 24.52% to 15.99%, while the solar cells with wide band gap HTMs including CuI, CuSCN and NiO show neglectable change, and the efficiency for p-Cu2O/i-BaSi2/n-BaSi2 solar cells decreases slightly from 25.86% to 24.88%. The performances of p-HTM/i-BaSi2/n-BaSi2 solar cells are affected by acceptor like defects more than donor like defects in i-BaSi2. [ABSTRACT FROM AUTHOR]

Perovskite solar cells have garnered the attention of researchers in recent years as they have been able to attain high efficiency within a short time. In the present study, the hybrid organic inorganic lead iodide perovskite has been used as the sensitizer. Successful fabrication of a hybrid lead halide perovskite sensitized solar cell (PSC) with copper iodide as a medium for transporting holes (HTM) has been performed in a sandwich structure. The synthesized CH3NH3PbI3 material and HTM have undergone various characterization processes, such as XRD, UV–Vis, SEM, and EDX. The present work is based on the synthesis of perovskite, HTM, and polymer electrolyte and their application in a PSC at room ambient following the sandwich structure. A planar WE/TiO2/CH3NH3PbI3/HTM/electrolyte/CE structure was fabricated through solution-processed spin-coating. The electrical properties of the PSC were measured through a solar simulator, and it attained an efficiency of 13.64%, with V oc = 0.63 V and Jsc = 33 mA cm 2 with fill factor = 0.65. This work shows the sandwich-structured fabrication of the PSC in ambient condition with a considerably good efficiency which represents the novelty of the work. [ABSTRACT FROM AUTHOR]

An immense volume of digital documents exists online and offline with content that can offer useful information and insights. Utilizing topic modeling enhances the analysis and understanding of digital documents. Topic modeling discovers latent semantic structures or topics within a set of digital textual documents. The Internet of Things, Blockchain, recommender system, and search engine optimization applications use topic modeling to handle data mining tasks, such as classification and clustering. The usefulness of topic models depends on the quality of resulting term patterns and topics with high quality. Topic coherence is the standard metric to measure the quality of topic models. Previous studies build topic models to generally work on conventional documents, and they are insufficient and underperform when applied to web content data due to differences in the structure of the conventional and HTML documents. Neglecting the unique structure of web content leads to missing otherwise coherent topics and, therefore, low topic quality. This study aims to propose an innovative topic model to learn coherence topics in web content data. We present the HTML Topic Model (HTM), a web content topic model that takes into consideration the HTML tags to understand the structure of web pages. We conducted two series of experiments to demonstrate the limitations of the existing topic models and examine the topic coherence of the HTM against the widely used Latent Dirichlet Allocation (LDA) model and its variants, namely the Correlated Topic Model, the Dirichlet Multinomial Regression, the Hierarchical Dirichlet Process, the Hierarchical Latent Dirichlet Allocation, the pseudo-document based Topic Model, and the Supervised Latent Dirichlet Allocation models. The first experiment demonstrates the limitations of the existing topic models when applied to web content data and, therefore, the essential need for a web content topic model. When applied to web data, the overall performance dropped an average of five times and, in some cases, up to approximately 20 times lower than when applied to conventional data. The second experiment then evaluates the effectiveness of the HTM model in discovering topics and term patterns of web content data. The HTM model achieved an overall 35% improvement in topic coherence compared to the LDA. [ABSTRACT FROM AUTHOR]

Purpose: This study measures the impact of implementation of the Improved Decentralized Maintenance Model on the functionality and availability of medical equipment in Burundi's resource constrained health care system with hypothesis that the model has a measurable impact. Methods: The initial model was tested in 2 provinces before being improved and extended to the provinces of Bujumbura and Rumonge. It is composed by 4 interrelated main axes (Maintenance management, Human, Financial and Material resources,). This study analyses the effects of this implementation between October 2020 and February 2022. Results: The rate of medical equipment functional in service has increased substantially, respectively +8% in the province of Bujumbura and 2% in the province of Rumonge, and the rate of medical equipment requiring maintenance has fallen by 9.7% (Bujumbura) and 2% (Rumonge). The provinces implementing the model have convincing results in terms of functionality with scores of at least 80%, while the national average is 64%. Conclusions: There is a notable positive change between 2020 and 2022 in the functionality of medical equipment and a decrease in equipment awaiting maintenance, and therefore in its availability. This study proves that a sustainable implementation of a decentralized maintenance model is feasible and highly useful in low-resource settings due to its affordability. The context of a low-resource country is a challenge in itself, but the model developed shows that by tackling the low-resource levels of preventive maintenance, we can have some impact on the functionality of the equipment and therefore on the quality of care. [ABSTRACT FROM AUTHOR]

The interest in video anomaly detection systems that can detect different types of anomalies, such as violent behaviours in surveillance videos, has gained traction in recent years. The current approaches employ deep learning to perform anomaly detection in videos, but this approach has multiple problems. For example, deep learning in general has issues with noise, concept drift, explainability, and training data volumes. Additionally, anomaly detection in itself is a complex task and faces challenges such as unknownness, heterogeneity, and class imbalance. Anomaly detection using deep learning is therefore mainly constrained to generative models such as generative adversarial networks and autoencoders due to their unsupervised nature; however, even they suffer from general deep learning issues and are hard to properly train. In this paper, we explore the capabilities of the Hierarchical Temporal Memory (HTM) algorithm to perform anomaly detection in videos, as it has favorable properties such as noise tolerance and online learning which combats concept drift. We introduce a novel version of HTM, named GridHTM, which is a grid-based HTM architecture specifically for anomaly detection in complex videos such as surveillance footage. We have tested GridHTM using the VIRAT video surveillance dataset, and the subsequent evaluation results and online learning capabilities prove the great potential of using our system for real-time unsupervised anomaly detection in complex videos. [ABSTRACT FROM AUTHOR]

The Spiro-OMeTAD is an excellent candidate for application as hole transport material (HTM), but its high hygroscopicity, inclination to crystallize, and fragility to moisture and heat make it unsuitable for solar cells. Thus, it is of interest to investigate other HTM candidates. In this paper, the use of p-type InGaAs as hole transport material (HTM) has been suggested to enhance the performance of perovskite-based solar cells (PSC). The simulation of a hybrid CH3NH3PbI3/InGaAs planar heterojunction perovskite solar cell is performed using the Silvaco ATLAS simulator. In order to confirm the predictability of the proposed simulation methodology, the conventional ITO/TiO2/MAPbI3/Spiro-OMeTAD structure is simulated, and shows good coherence with experimental results. The proposed design using InGaAs as HTM outperforms the conventional device in terms of short-circuit current density (JSC) of 37.2 mA/cm2, open-circuit voltage (VOC) of 1 V, fill factor (FF) of 80% and high value of efficiency. In addition, the findings show that with In content of x = 0.7 the efficiency will improve to reach a value of about 30%. [ABSTRACT FROM AUTHOR]

High efficiency perovskite solar cells are usually achieved with expensive hole transport materials (HTM), such as PTAA and Spiro-OMeTAD. To bring this technology to industry it is essential to find alternative HTM. In this work, we show results with the inexpensive inorganic semiconductor CuSCN as HTM in inverted device structure. We first studied the interaction between CuSCN and the perovskite solution by performing solubility test and found out that CuSCN can be dissolved in perovskite solution. Then devices were fabricated using single-step deposition technique and sequential deposition technique were first a PbI2 layer is first deposited that could overcome the potential incompatibility of the perovskite solution with the CuSCN. Solar cells with Voc > 1000 mV were successfully fabricated with the 2-step process but demonstrated lower efficiencies compared to the 1-step process due to a lower Jsc. [ABSTRACT FROM AUTHOR]

In just a few years, the efficiency of perovskite-based solar cells (PSCs) has risen to 25.8%, making them competitive with current commercial technology. Due to the inherent advantage of perovskite thin films that can be fabricated using simple solution techniques at low temperatures, PSCs are regarded as one of the most important low-cost and mass-production prospects. The lack of stability, on the other hand, is one of the major barriers to PSC commercialization. The goal of this review is to highlight the most important aspects of recent improvements in PSCs, such as structural modification and fabrication procedures, which have resulted in increased device stability. The role of different types of hole transport layers (HTL) and the evolution of inorganic HTL including their fabrication techniques have been reviewed in detail in this review. We eloquently emphasized the variables that are critical for the successful commercialization of perovskite devices in the final section. To enhance perovskite solar cell commercialization, we also aimed to obtain insight into the operational stability of PSCs, as well as practical information on how to increase their stability through rational materials and device fabrication. [ABSTRACT FROM AUTHOR]

Perovskite Solar Cells (PSCs) being the most advanced photovoltaic technology today have attracted global attention due to its solution processability and cost effectiveness. In this paper, we reported the performance of perovskite solar cells by integrating Reduced Graphene Oxide (rGO) as a buffer layer. The combined effect of Ultraviolet visible (UV-vis) spectroscopy, X-ray Diffractometer (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Four Point Probe and Solar Simulator were used to explore the absorbance, crystallinity, morphological, resistivity and current voltage behavior of the photoanodes and devices. The rGO was deposited on top the mesoporous Titanium dioxide (m-TiO2) (Device B), on methylammonium lead triiodide (CH3NH3PbI3) perovskite absorber (Device C) and on m-TiO2 & CH3NH3PbI3 perovskite absorber (Device D). The reference device (Device A) was fabricated without rGO as a bench mark for comparison. From the results obtained, the devices with rGO show significant improvement over the device lacking rGO. The reference device gave a Short Circuit Current Density (Jsc) of 8.151 mAcm-2, Open Circuit Voltage (Voc) of 0.575 V, Fill Factor (FF) of 74.4 % and Power Conversion Efficiency (PCE) of 3.49 %. The best performing device was the one with rGO incorporated on both m-TiO2 and CH3NH3PbI3. The device gave a Jsc of 8.737 mAcm-2, Voc of 0.836 V, FF of 68.1% and PCE of 4.98 %. The device experienced an enhancement of ~7.20 % and 42.69 % in Jsc and PCE over the pristine device. This investigation aids the fundamental understanding of the effect of Graphene Materials (GRMs) on the optoelectronic properties of PSCs, and it further confirms the promising prospects of achieving low-cost, efficient and stable PSCs for commercialization with graphene materials. [ABSTRACT FROM AUTHOR]

Abstract.Inverted Bulk heterojunctions (Ag/MoO3/PCDTBT-PC70BM/ZnO/ITO) Organic Solar cells, based on Organic (Polymer) materials is fabricated and characterized in this work. PCDTBT-PC70BM was synthesized by chloroform, chlorobenzene and odichlorobenzene (organic solvent). Surface morphology of ZnO and PCDTBT-PC70BM were studied. Bulk heterojunctions of active material are formed by the mixture of PCDTBT donor and PC70BM an acceptor in a random manner. For Sufficient transportation of charge carrier (electron and hole), hole transport (HT) and electron transport (ET) layers was deposited. ZnO is used as an ETM and synthesized by using Sol-Gel technique. MoO3 thin film deposited over the active material, enhances hole transformation because of band gap tuning with Ag and active materials. Absorbance and Photoluminescence spectra of polymer material with different organic solvents were studied and results were discussed in this work. o-dichlorobenzene enhance the absorption of PCDTBT/PC70BM. At 400 nm, 90% of sun light is absorbed, and 70% absorption is figure out in 500- 550nm wavelength. The Photo-luminescence of PCDTBT/PC70BM thin film in different organic solvents is ranging from 650nm to 750nm. At 700nm, 20% is shown for chloroform, 40% for chlorobenzene and highest 80% is achieved by o-dichlorobenzene. J-V value is obtained from a solar simulator which irradiates the sun spectrum 1.5 AM, for all the devices having cell area 0.045 cm². For concentration (1:1) ratio in different organic solvents like chloroform, chlorobenzene and o-dichlorobenzene, (3.5, 4.2, and 5.8) %, PCE were obtained respectively. [ABSTRACT FROM AUTHOR]

An ultimate goal of placing fire detection systems in buildings and structures is to allow for the rapid detection of fire and accurate faster than real time prediction of ensuing fire behavior so that relevant information can be delivered to the appropriate stakeholders. In the near-term, development of detection systems with decreased detection time, better discrimination against nuisance and false alarms, and real-time monitoring of the fire state is a critical interim step. Building comfort and efficiency systems are increasingly incorporating a greater quantity of sensors and these sensors are installed at a greater density than any fire sensor with the exception of the sprinkler. While currently used primarily for building management purposes, the application of these, or similar types of building sensors, for rapid fire detection, fire state determination, and fire forecasting offers great potential. This paper discusses the potential benefits of the application of Hierarchical Temporal Memory algorithms for fire state determination in a continuous learning environment based on its application to a series of live fire experiments. [ABSTRACT FROM AUTHOR]

With the development of intrusion detection, a number of the intelligence algorithms (e.g., artificial neural networks) are introduced to enhance the performance of the intrusion detection systems. However, many intelligence algorithms should be trained before being used, and retrained regularly, which is not applicable for continuous online learning and analyzing. In this paper, a new online intrusion scenario discovery framework is proposed and the intelligence algorithm HTM (Hierarchical Temporal Memory) is employed to improve the performance of the online learning ability of the system. The proposed framework can discover and model intrusion scenarios, and the constructed model keeps evolving with the variance of the data. Additionally, a series of data preprocessing methods are introduced to enhance its adaptability to the noisy and twisted data. The experimental results show that the framework is effective in intrusion scenario discovery, and the discovered scenario is more concise and accurate than our previous work. [ABSTRACT FROM AUTHOR]

Six materials were used as an interlayer at the anode side (anode interlayer [AIL]) of an archetypical planar heterojunction organic solar cell (OSC). In addition to two conventional wide bandgap hole transport materials (HTMs), tris(4‐carbazol‐9‐ylphenyl)amine (TCTA) and trans‐4,4′‐bis[N‐(naphthalen‐1‐yl)‐N‐phenylamino]stilbene (NPAE), we explore four narrow bandgap materials, bis(biphenylaminospiro)‐fumaronitrile (PhSPFN), bis(N‐(naphthalen‐1‐yl)‐N‐phenylamino)anthraquinone (NPAAnQ), bis‐(di(2‐fluorophenyl)aminospiro)‐fumaronitrile (FPhSPFN), and bis[4‐(N‐(pyren‐1‐yl)‐N‐phenylamino)phenyl]fumaronitrile (PyPAFN), the energy levels of which essentially align with the ones of SubPc, the active light‐absorbing material of the OSC study herein. By using a narrow bandgap AIL, universally enhanced short‐circuit current density and power conversion efficiencies (PCEs) have been achieved. In addition, one of these materials, FPhSPFN, results in a PCE of 5.13%, which is the highest reported value for SubPc solar cells with a similar architecture. This is ascribed to the formation of an otherwise passive exciton‐blocking interface. Furthermore, this demonstrates that charge selectivity by way of a high‐lying lowest unoccupied molecular orbital (LUMO) energy level is not a prerequisite for successful AIL design. As such, in terms of energy level alignment and bandgap energies, we establish a viable alternative approach toward interface and interlayer material design. [ABSTRACT FROM AUTHOR]

In this work, easy and simple structured perovskite solar cells (PSCs) are designed and characterized. Our effort was to reduce the cost of the fabrication of such PSC devices, first by using an inexpensive starting precursor (aqueous methylamine solution) for the perovskite materials and second by design in a PSC structure free of the expensive hole transport layer (HTL). The CH3NH3PbI3 perovskite sols were deposited onto a conductive FTO glass using the spin coating technique followed by heating at 100 °C for 10 min. The structure of the films was characterized by X-ray diffraction (XRD) and their optical properties by UV–VIS spectrophotometry and photoluminescence (PL). The obtained phase confirmed the formation of a tetragonal perovskite structure. Two different solvents have been used, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The effect of the type and the concentration of the used solvent DMF and DMSO on the performance of the solar cells have been investigated. It was found that a 40% concentration of the perovskite material resulted in the optimum film thickness that gives the best photoelectric performance. The DMF-based PSC assembled solar cell exhibited the best performance with an open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2, and an overall photon to electric conversion efficiency of 5.7%; all these results are higher than those of cells made with DMSO. Highlights: Easy and simple structured perovskite solar cells free of the hole transport layer were designed for efficient low-cost organolead halide perovskites solar cells by using inexpensive precursors. The influence of the concentration and the type of the solvent of the obtained perovskite materials on the performance of the solar cell have been investigated. For both the used solvents (DMF and DMSO), it was found that a 40% concentration is the optimum to obtain better performance for the DMF-based PSC. An open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2 with an overall photon to electric conversion efficiency of 5.7% was obtained. [ABSTRACT FROM AUTHOR]

Abstract: This study reports design and synthesis of cone shaped hole transporting materials (HTM, i. e., H1 and H2). They are based on triphenylamine (TPA) and phenothiazine donors attached with two TPA moiety via electron rich π‐spacer (phenyl acrylonitrile). π‐spacers are proven to enhance the power conversion efficiency (PCE) of perovskite solar cells (PSCs) in the literature. Due to the electron withdrawing nature of the π‐spacer and the extended conjugation present in the HTMs proposed, a gradient for charge flow within the molecule is expected. This property is essential to transfer the electron from the HOMO of HTMs to the valence band of the perovskite via the arms of the HTMs. These HTMs do not show strong absorption in the visible region, exhibit high stokes shift and have their HOMO positioned above the perovskite's valence band. HTM layer of the PSCs were fabricated by a solution process method, at ambient conditions. A PCE of ∼1.9% at 1 sun condition was obtained, while under similar conditions the standard HTM (S‐OMeTAD) exhibited a PCE of 1.3%. [ABSTRACT FROM AUTHOR]

Abstract: The photovoltaic characteristics of CsBi3I10‐based solar cells with three dopant‐free hole‐conducting polymers are investigated. The effect on charge generation and charge recombination in the solar cells using the different polymers is studied and the results indicate that the choice of polymer strongly affects the device properties. Interestingly, for the solar cell with poly[[2,3‐bis(3‐octyloxyphenyl)‐5,8‐quinoxalinediyl]‐2,5‐thiophenediyl] (TQ1), the photon‐to‐current conversion spectrum is highly improved in the red wavelength region, suggesting that the polymer also contributes to the photocurrent generation in this case. This report provides a new direction for further optimization of Bi–halide solar cells by using dopant‐free hole‐transporting polymers and shows that the energy levels and the interaction between the Bi–halide and the conducting polymers are very important for solar cell performance. [ABSTRACT FROM AUTHOR]

Hierarchical Temporal Memory is a new machine learning algorithm intended to mimic the working principle of the neocortex, part of the human brain, responsible for learning, classification, and making predictions. Although many works illustrate its effectiveness as a software algorithm, hardware design for HTM remains an open research problem. Hence, this work proposes an architecture for HTM Spatial Pooler and Temporal Memory with learning mechanism, which creates a single image for each class based on important and unimportant features of all images in the training set. In turn, the reduction in the number of templates within database reduces the memory requirements and increases the processing speed. Moreover, face recognition analysis indicates that for a large number of training images, the proposed design provides higher accuracy results (83.5%) compared to only Spatial Pooler design presented in the previous works. [ABSTRACT FROM AUTHOR]

The organometal perovskite solar cells have shown stupendous development and have reached a power conversion efficiency (PCE) of 22.1%. However, the toxicity of lead in perovskite solar cells is a major challenge towards their incorporation into photovoltaic devices and thus needs to be addressed. Tin perovskite (CH3NH3SnI3) have attracted a lot of attention recently and could be a viable alternative material to replace lead perovskite in thin film solar cells. A detail understanding of effects of each component of a solar cell on its output performance is needed to further develop the technology. In this work, we performed a numerical simulation of a planar heterojunction tin based perovskite solar cell using SCAPS (Solar Cell Capacitance Simulator). Results revealed that thickness and defect density of the absorber material strongly influence the PCE of the device. Various types of hole transporting material (HTM) were compared and analysed to improve the performance of the solar cell. Parameters such as hole mobility and acceptor density of HTM also signified dependence on PCE of the device. These results indicate the possibility to design, fabricate and enhance the performance of tin based perovskite solar cells. [ABSTRACT FROM AUTHOR]

We have fabricated solution processed organic light-emitting devices (OLEDs) with various hole transporting materials (HTMs) on the plastic substrate. The device structure was ITO/HTM:Ir(2-phq)31wt%:FIrpic 5wt% (50 nm)/TAZ (50 nm)/LiF (0.5 nm)/Al (100 nm). 4,4′-bis(carbazol-9-yl)biphenyl (CBP), di-[4-(N,N-ditolyl-amino)-phenyl]cyclohexane (TAPC), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD), and poly(9-vinylcarbazole) (PVK) were used for HTM. Phosphorescent orange-red emitting Ir(2-phq)3and blue emitting FIrpic guest molecules were mixed with the HTMs and solvents. OLED with TAPC exhibited the maximum current efficiency of 17.4 cd/A at 0.42 mA/cm2. [ABSTRACT FROM AUTHOR]

Effective engineering of surface ligands in semiconductor nanocrystals can facilitate the electronic interaction between the individual nanocrystals, making them promising for low-cost optoelectronic applications. Here, the use of high purity Cu2ZnSnS4 (CZTS) nanocrystals as the photoactive layer and hole-transporting material is reported in low-temperature solution-processed solar cells. The high purity CZTS nanocrystals are prepared by engineering the surface ligands of CZTS nanocrystals, capped originally with the long-chain organic ligand oleylamine. After ligand removal, CZTS nanocrystals show substantial improvement in photoconductivity and mobility, displaying also an appreciable photoresponse in a simple heterojunction solar cell architecture. More notably, CZTS nanocrystals exhibit excellent hole-transporting properties as interface layer in perovskite solar cells, yielding power conversion efficiency (PCE) of 15.4% with excellent fill factor (FF) of 81%. These findings underscore the importance of removing undesired surface ligands in nanocrystalline optoelectronic devices, and demonstrate the great potential of CZTS nanocrystals as both active and passive material for the realization of low-cost efficient solar cells. [ABSTRACT FROM AUTHOR]

An attempt has been made to fabricate methyl ammonium tin chloride (CHNHSnCl) perovskite-sensitized TiO nanostructure photoanode solar cell with hole transport material (HTM) spiro-MeOTAD and graphite-coated counter electrode (CE). The TiO nanoparticles (TNPs), TiO nanoleaves (TNLs), and TNLs with MgO core/shell photoanodes were prepared to fabricate perovskite-sensitized solar cells (PSSCs). The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photovoltaic characteristics of the PSSCs, photocurrent density ( J ), open-circuit voltage ( V ), fill factor (FF), and power conversion efficiency (PCE) were determined under illumination of AM 1.5 G. Electrochemical impedance spectroscopy (EIS) analysis was carried out to study the charge transport and lifetime of charge carriers at the photoanode-sensitizer-electrolyte interface of the PSSCs. The PSSC made with CHNHSnCl perovskite-sensitized TNL-MgO core/shell photoanode and spiro-MeOTAD HTM shows an impressive photovoltaic performance, with J = 17.24 mA/cm, V = 800 mV, FF = 73 %, and PCE = 9.98 % under 100 mW/cm light intensity. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost and high-efficiency solar cells. By the aid of electrochemical impedance spectroscopy, it is revealed that the core/shell structure can increase an interfacial resistance of the photoanode-CHNHSnCl interface and retard an electron recombination process in the photoanode-sensitizer-HTM interface. [ABSTRACT FROM AUTHOR]

This work investigates the proficiency of acceptor-donor-acceptor (A-D-A) organic dye Diisopropyl azodicarboxylate (DIAC) as photosensitizer on the photovoltaic parameters of silver (Ag) doped TiO photoanode dye-sensitized solar cells (DSSCs) with quasi-solid state electrolyte/hole transport material (HTM) spiro-MeOTAD. TNSs (TiO nanosticks) photoanodes are prepared through sol-gel method and hydrothermal technique. X-ray powder diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and BET measurement were used to characterize the structure and morphology of TiO nanostructures. The Diisopropyl azodicarboxylate organic dye with TNPs-Ag@TNSs composite photoanode structure and spiro-MeOTAD HTM exhibited better power conversion efficiency (PCE). [ABSTRACT FROM AUTHOR]

Background: Glaucoma is the largest cause of irreversible blindness affecting more than 60 million people globally. The disease is defined as a gradual loss of peripheral vision due to death of Retinal Ganglion Cells (RGC). The RGC death is largely influenced by the rate of aqueous humor production by ciliary processes and its passage through the trabecular meshwork (TM) in the anterior part of the eye. Primary open angle glaucoma (POAG), the most common subtype, is a genetically complex disease. Multiple genes and many loci have been reported to be involved in POAG but taken together they explain less than 10% of the patients from a genetic perspective warranting more studies in different world populations. The purpose of this study was to perform genome-wide search for common variants associated with POAG in an east-Indian population. Methods: The study recruited 746 POAG cases and 697 controls distributed into discovery and validation cohorts. In the discovery phase, genome-wide genotype data was generated on Illumina Infinium 660 W-Quad platform and the significant SNPs were genotyped using Illumina GGGT assay in the second phase. Logistic regression was used to test association in the discovery phase to adjust for population sub-structure and chi-square test was used for association analysis in validation phase. Publicly available expression dataset for trabecular meshwork was used to check for expression of the candidate gene under cyclic mechanical stress. Western blot and immunofluorescence experiments were performed in human TM cells and murine eye, respectively to check for expression of the candidate gene. Results: Meta-analysis of discovery and validation phase data revealed the association of rs7916852 in MPP7 gene (p = 5.7×10-7) with POAG. We have shown abundant expression of MPP7 in the HTM cells. Expression analysis shows that upon cyclic mechanical stress MPP7 was significantly down-regulated in HTM (Fold change: 2.6; p = 0.018). MPP7 protein expression was also found to be enriched in the ciliary processes of the murine eye. Conclusion: Using a genome-wide approach we have identified MPP7 as a novel candidate gene for POAG with evidence of its expression in relevant ocular tissues and dysregulation under mechanical stress possibly mimicking the disease scenario. [ABSTRACT FROM AUTHOR]

Hybrid organometal halide perovskites have attracted much attention these past four years as the new active layer for photovoltaic applications. Researches are now intensively focused on the stability issues of these solar cells, the process of fabrication and the design of innovative materials to produce efficient perovskite devices. In this review, we highlight the recent progress demonstrated in 2015 in the design of new π-conjugated organic materials used as hole transporters in such solar cells. Indeed, several of these "synthetic metals" have been proposed to play this role during the last few years, in an attempt to replace the conventional 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (Spiro-OMeTAD) reference. Organic compounds have the benefits of low production costs and the abundance of raw materials, but they are also crucial components in order to address some of the stability issues usually encountered by this type of technology. We especially point out the main design rules to reach high efficiencies. [ABSTRACT FROM AUTHOR]

This paper introduces a two-stage approach to the detection of people eating and/or drinking for the purposes of surveillance of daily life. With the sole use of wearable accelerometer sensor attached to somebody's (man or a woman) wrists, this two-stage approach consists of feature extraction followed by classification. At the first stage, based on the limb's three dimensional kinematics movement model and the Extended Kalman Filter (EKF), the realtime arm movement features described by Euler angles are extracted from the raw accelerometer measurement data. In the latter stage, the Hierarchical Temporal Memory (HTM) network is adopted to classify the extracted features of the eating/drinking activities based on the space and time varying property of the features, by making use of the powerful modelling capability of HTM network on dynamic signals which is varying with both space and time. The proposed approach is tested through the real eating and drinking activities using the three dimensional accelerometers. Experimental results show that the EKF and HTM based two-stage approach can perform the activity detection successfully with very high accuracy. [ABSTRACT FROM AUTHOR]

Summary Haematopoietic cell-specific transmembrane-4 (HTm4) is a four-transmembrane protein most closely related to CD20 and the beta subunit of the high affinity receptor for IgE (FcℇRIβ). To date, it has only been described in humans, where it is expressed in haematopoietic cells of both myeloid and lymphoid lineages. The function of HTm4 is unknown; however, as for CD20 and FcℇRI-β, it is likely to play a role in signal transduction as part of a multi-subunit cell surface receptor complex. In this study, we report the cDNA cloning and expression distribution of mouse HTm4. The deduced mouse HTm4 protein is of 213 amino acids, and contains four putative transmembrane domains. Mouse HTm4 shows 62% overall amino acid identity with human HTm4; the transmembrane regions are highly conserved between both species (75% identity), whereas the N- and C-terminal and inter-transmembrane loop regions are more divergent (52%). Interestingly, the N-terminal domain of mouse HTm4 is predicted to be 23 amino acids shorter, and the C-terminal domain 23 amino acids longer, than that of human HTm4. Northern blot and reverse transcriptase (RT)-PCR analysis suggest that mouse HTm4 mRNA is expressed at low levels only in spleen, bone marrow and peripheral blood leucocytes. This is the first report of the cloning of HTm4 from a species other than human, and provides important sequence information towards the understanding of the function of this poorly characterized four-transmembrane molecule. [ABSTRACT FROM AUTHOR]

Over the years, and with the emergence of various technological innovations, the relevance of automatic learning methods has increased exponentially, and they now play a key role in society. More specifically, Deep Learning (DL), with the ability to recognize audio, image, and time series predictions, has helped to solve various types of problems. This paper aims to introduce a new theory, Hierarchical Temporal Memory (HTM), that applies to stock market prediction. HTM is based on the biological functions of the brain as well as its learning mechanism. The results are of significant relevance and show a low percentage of errors in the predictions made over time. It can be noted that the learning curve of the algorithm is fast, identifying trends in the stock market for all seven data universes using the same network. Although the algorithm suffered at the time a pandemic was declared, it was able to adapt and return to good predictions. HTM proved to be a good continuous learning method for predicting time series datasets. [ABSTRACT FROM AUTHOR]

Copper oxide (CuxO) films are considered to be an attractive hole-transporting material (HTM) in the inverted planar heterojunction perovskite solar cells due to their unique optoelectronic properties, including intrinsic p-type conductivity, high mobility, low-thermal emittance, and energy band level matching with the perovskite (PS) material. In this study, the potential of reactive sputtered CuxO thin films with a thickness of around 100 nm has been extensively investigated as a promising HTM for effective and stable perovskite solar cells. The as-deposited and annealed films have been characterized by using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Photoluminescence (PL), UV-Vis spectroscopy, and Hall-effect measurement techniques. The significant change in structural and optoelectronic properties has been observed as an impact of the thermal annealing process. The phase conversion from Cu2O to CuO, including grain size increment, was observed upon thermal annealing. The transmittance and optical bandgap were found to vary with the films' crystallographic transformation. The predominant p-type conductivity and optimum annealing time for higher mobility have been confirmed from the Hall measurement. Films' optoelectrical properties were implemented in the complete perovskite solar cell for numerical analysis. The simulation results show that a 40 min annealed CuxO film yields the highest efficiency of 22.56% with a maximum open-circuit voltage of 1.06 V. [ABSTRACT FROM AUTHOR]

Planar perovskite solar cells were fabricated on F-doped SnO2 (FTO) coated glass substrates, with 4,4'-((1E,1'E)-((1,2,4-thiadiazole-3,5-diyl)bis(azaneylylidene))bis(methaneylylidene))bis(N,N-di-p-tolylaniline) (bTAThDaz) as hole transport material. This imine was synthesized in one step reaction, starting from commercially available and relatively inexpensive reagents. Electrochemical, optical, electrical, thermal and structural studies including thermal images and current-voltage measurements of the full solar cell devices characterize the imine in details. HOMO-LUMO of bTAThDaz were investigated by cyclic voltammetry (CV) and energy-resolved electrochemical impedance spectroscopy (ER-EIS) and were found at −5.19 eV and −2.52 eV (CV) and at −5.5 eV and −2.3 eV (ER-EIS). The imine exhibited 5% weight loss at 156 °C. The electrical behavior and photovoltaic performance of the perovskite solar cell was examined for FTO/TiO2/perovskite/bTAThDaz/Ag device architecture. Constructed devices exhibited good time and air stability together with quite small effect of hysteresis. The observed solar conversion efficiency was 14.4%. [ABSTRACT FROM AUTHOR]

Summary: We introduce the first concurrent data structure algorithm designed for speculative executions. Prior to this work, concurrent structures were mainly designed for their pessimistic (non‐speculative) accesses to have a predictable asymptotic complexity. Researchers tried to evaluate transactional memory using such structures whose prominent example is the red‐black tree library developed by Oracle Labs that is part of multiple benchmark distributions. Although well‐engineered, such structures remain badly suited for speculative accesses, whose step complexity might raise dramatically with contention. We propose a binary search tree data structure whose key novelty stems from the decoupling of update operations, ie, instead of performing an update operation in a single large transaction, it is split into one transaction that modifies the abstraction state and several other transactions that restructure the tree implementation in the background. This results in a speculation‐friendly tree (s‐tree) that outperforms previous HTM‐based and STM‐based trees by being transiently unbalanced during contention peaks and by rebalancing in quadratic time when contention disappears. In particular, the s‐tree is shown correct, reusable, and speeds up a transaction‐based travel reservation application by up to 3.5×. [ABSTRACT FROM AUTHOR]