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Poor landing biomechanics such as hip adduction, internal rotation, and knee valgus have been recognized as modifiable risk factors of anterior cruciate ligament (ACL) injury. Dynamic taping is a newly developed technique with better elasticity and extensibility, which could change the landing biomechanics. The purpose of this study was to identify whether dynamic taping could improve lower limb biomechanics in athletes. Forty-two high school volleyball athletes (21 males and 21 females) participated in the study. Biomechanical properties, including the landing error scoring system (LESS) and anterior–posterior knee laxity, were evaluated before and after the application of dynamic tape while athletes performed the jump-landing task. As a result, we found that dynamic tape significantly reduced the faulty landing strategy by an average of 0.64 errors in all volleyball athletes. The effect induced by dynamic tape was more prominent in female athletes and high-risk athletes (1.1 errors). Furthermore, the application of dynamic tape improved anterior–posterior knee laxity, especially in female athletes (p < 0.001). In conclusion, we found that dynamic tape provided a short-term, passive, and clinically significant means to normalize inadequate biomechanics during landing in athlete groups, which could have a protective effect and further alleviate the risk of ACL injury.

Introduction Pneumocephalus and cerebrospinal fluid (CSF) leaks are uncommon after trauma, but they expose the sterile CSF to environmental pathogens and create theoretical risk of central nervous system infection (CNSI). Prophylactic antibiotics are commonly given to these patients, but there is a paucity of evidence to guide this practice. We aim to quantify the incidences of these entities and analyze the efficacy of prophylactic antibiotics in preventing CNSIs. Methods A retrospective cohort study was conducted using our institutional trauma registry. All patients admitted from January 2014 to July 2020 with traumatic pneumocephalus (TP) or basilar skull fracture with CSF leak (BSF-CSF) were included. ICD-9 and ICD-10 codes were used to identify CNSIs. CNSI rates among defined prophylactic antibiotic regimens, no antibiotics, and other antibiotic regimens were evaluated. ANOVA was used to analyze differences between the groups. Results 365 patients met inclusion criteria: 360 with TP; 5 with BSF-CSF. 1.1% (4/365) of patients developed CNSI, all with isolated traumatic pneumocephalus. 1.4% of patients (1/72) without antibiotics; 1.2% (3/249) receiving IV antibiotics outside of a defined regimen; and 1.1% (1/88) on a designated prophylactic regimen developed CNSIs. ANOVA indicated the incidence of CNSI was not significantly different among patients who received antibiotics or not, regardless of the regimen (p-value 0.958). Conclusion TP and BSF-CSF are rare diagnoses among trauma patients. The rate of CNSI is marginal and antibiotics do not appear to confer a protective advantage. A larger trial is needed to elucidate the true effect of antibiotics on preventing CNSIs in patients with these uncommon diagnoses.

The P1/HC-Pro viral suppressor of potyvirus suppresses posttranscriptional gene silencing (PTGS). The fusion protein of P1/HC-Pro can be cleaved into P1 and HC-Pro through the P1 self-cleavage activity, and P1 is necessary and sufficient to enhance PTGS suppression of HC-Pro. To address the modulation of gene regulatory relationships induced by turnip mosaic virus (TuMV) P1/HC-Pro (P1/HC-ProTu), a comparative transcriptome analysis of three types of transgenic plants (P1Tu, HC-ProTu, and P1/HC-ProTu) were conducted using both high-throughput (HTP) and low-throughput (LTP) RNA-Seq strategies. The results showed that P1/HC-ProTu disturbed the endogenous abscisic acid (ABA) accumulation and genes in the signaling pathway. Additionally, the integrated responses of stress-related genes, in particular to drought stress, cold stress, senescence, and stomatal dynamics, altered the expressions by the ABA/calcium signaling. Crosstalk among the ABA, jasmonic acid, and salicylic acid pathways might simultaneously modulate the stress responses triggered by P1/HC-ProTu. Furthermore, the LTP network analysis revealed crucial genes in common with those identified by the HTP network in this study, demonstrating the effectiveness of the miniaturization of the HTP profile. Overall, our findings indicate that P1/HC-ProTu-mediated suppression in RNA silencing altered the ABA/calcium signaling and a wide range of stress responses.

Precise allele replacement (genome editing), without unwanted changes to the genome, provides a powerful tool to define the functions of DNA elements and encoded factors in their normal biological context. While CRISPR is now used extensively for gene targeting, its utility for precise allele replacement at population scale is limited because: (A) there is a strict requirement for a correctly positioned PAM motif to introduce recombinogenic dsDNA breaks (DSBs); (B) efficient replacements only occur very close to the DSBs; and (C) indels and off-target changes are frequently generated. Here we show, using a saturated mutation library with about 15,000 alleles of the ade6 gene of Schizosaccharomyces pombe, that pop-in, pop-out allele replacement circumvents these problems. Two rounds of selection ensure that clones arise by homologous recombination with the target locus. Moreover, the exceptionally high efficiency allows one to carry out the process in bulk, then screen individual clones for phenotypes and genotypes. Alleles were introduced successfully throughout the region targeted, up to 1,956 base pairs from the DSB. About 11% of mutant alleles were hypomorphic, demonstrating utility for analyses of essential genes and genetic elements. This process of “targeted forward genetics” can be used to analyze comprehensively, across thousands of base pairs within a specific target region, a variety of allelic changes, such as scanning amino acid substitutions, deletions, and epitope tags. The overall approach and optimized workflow are extensible to other organisms that support gene targeting.

Hierarchical silicon structures consisting of micropyramids and nanowire arrays are fabricated by two-step chemical etching processes aimed at achieving cost and time effectiveness constraints without using any expensive vacuum system or complicated lithography process. The hierarchical structures can suppress the average reflectance to as low as 4.3% from 300 to 1100 nm without causing poor minority carrier lifetimes, exhibiting excellent broadband light-harvesting abilities with minimal recombination losses, which is the key point to design high-performance nanostructured solar cells. By utilizing hierarchical structures in the practical solar cells application, the short-circuit current density (JSC) shows a significant enhancement from 21.5 to 28.7 mA/cm2, and the conversion efficiency is enhanced by a factor of 35%. Such a significant enhancement is attributed not only to the superior light harvesting achieved by hierarchical structures but also to the benefit of small electrical losses in the solar cells. Thus, the concept and technique presented in this paper open avenues for developing high-performance structure solar devices.

Thigmotaxis is required in small animals. In this study, we examined how the shelter angle affects the development of German cockroaches

Airborne particulate matter 2.5 (PM2.5) can have a profound effect on the health of the population. Many researchers have been reporting highly accurate numerical predictions based on raw PM2.5 data imported directly into deep learning models, however, there is still considerable room for improvement in terms of implementation costs due to heavy computational overhead. From the perspective of environmental science, PM2.5 values in a given location can be attributed to local sources as well as external sources. Local sources tend to have a dramatic short-term impact on PM2.5 values, whereas external sources tend to have more subtle but longer-lasting effects. In the presence of PM2.5 from both sources at the same time, this combination of effects can undermine the predictive accuracy of the model. This paper presents a novel combinational Hammerstein recurrent neural network (CHRNN) to enhance predictive accuracy and overcome the heavy computational and monetary burden imposed by deep learning models. The CHRNN comprises a based-neural network tasked with learning gradual (long-term) fluctuations in conjunction with add-on neural networks to deal with dramatic (short-term) fluctuations. The CHRNN can be coupled with a random forest model to determine the degree to which short-term effects influence long-term outcomes. We also developed novel feature selection and normalization methods to enhance prediction accuracy. Using real-world measurement data of air quality and PM2.5 datasets from Taiwan, the precision of the proposed system in the numerical prediction of PM2.5 levels was comparable to that of state-of-the-art deep learning models, such as deep recurrent neural networks and long short-term memory, despite far lower implementation costs and computational overhead.

Remote sensing technology has rendered lots of information in agriculture. It has usually been used to monitor paddy growing ecosystems in the past few decades. However, there are uncertainties in data fusion techniques which can be resolved in image classification on paddy rice. In this study, a series of learning concepts integrated by a probability progress Fuzzy Dempster-Shafer (FDS) analysis is presented to upgrade various models and different types of image data which is the goal of this study. More specifically, the study utilized the FDS to generate a series of probability models in the classification of the system. In addition, Logistic Regression (LR), Support Vector Machine (SVM), and Neural Network (NN) approaches are employed into the developed FDS system. Furthermore, two different image types are Satellite Image and Aerial Photo used as the analysis material. The overall classification accuracy has been improved to 97.27%, and the kappa value is 0.93. The overall accuracy of the paddy field image classification for a multi-period of mid-scale satellite images is between 85% and 90%. The overall accuracy of the classification using multi-spectral numerical aerial photos can be between 91% and 95%. The FDS improves the accuracy of the above image classification results.

Metal halide perovskites (MHPs) have been a hot research topic due to their facile synthesis, excellent optical and optoelectronic properties, and record-breaking efficiency of corresponding optoelectronic devices. Nowadays, the development of miniaturized high-performance photodetectors (PDs) has been fueling the demand for novel photoactive materials, among which low-dimensional MHPs have attracted burgeoning research interest. In this report, the synthesis, properties, photodetection performance, and stability of low-dimensional MHPs, including 0D, 1D, 2D layered and nonlayered nanostructures, as well as their heterostructures are reviewed. Recent advances in the synthesis approaches of low-dimensional MHPs are summarized and the key concepts for understanding the optical and optoelectronic properties related to the PD applications of low-dimensional MHPs are introduced. More importantly, recent progress in novel PDs based on low-dimensional MHPs is presented, and strategies for improving the performance and stability of perovskite PDs are highlighted. By discussing recent advances, strategies, and existing challenges, this progress report provides perspectives on low-dimensional MHP-based PDs in the future.

The rapid rise in efficiency and tunable bandgap of metal-halide perovskites makes them highly attractive for use in tandems on silicon. Recently we demonstrated a perovskite–silicon monolithic two...

Flexible optoelectronics that can be bent, wrapped, and stretched have attracted interest for wearable and mobile applications. In this work, we demonstrate a transparent 360° omnidirectional photodetector (PD) that can be stretched and wrapped around flexible or curved substrates. By embedding interlaced ZnO and Ag nanowires (NWs) in thermoplastic polyurethane via inkjet printing, the device featured > 75% transmittance in the visible region, showing high photoresponsivity and response time (10–30 A/W and 0.8 s, respectively). Moreover, the flexible PD performs well under deformation (only 9% decay in the photocurrent under 60% strain and 8% loss when the device is bent at a radius of 5 mm), which allows it to be readily applied on curved surfaces, such as skin or optical fibers. This study opens the door for the development of flexible optoelectronics that could be implemented in fiber optics, wearable electronics, self-powered systems, bio-signal monitors, and epidermal electronics. Ink-jet printed nanowire network-polymer composites enable flexible, transparent photodetectorsthat can be bent, wrapped, and stretched.A collaborative team lead by Jr-Hau He from the Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division at King Abdullah University of Science and Technology (KAUST) developed ink-jet printed 360° omnidirectional photodetectors that are fully transparent, stretchable and wrappable. The key to the device’s high degree of functionality is a polyurethane-based composite consisting of a ZnO-Ag interlaced nanowire network. Incorporating the composite into the device structure leads to photodetectors with over 75% transmittance, which enables omnidirectional photodetection with only 78% variation. The device operates under less than 5 mm bending radius and while stretched at over 60% strain, which allows the device to employed in applications such as wearable electronics.

Launching a new store is one of the most important decisions a proprietor must make, with the placement of the store making the difference between financial success and financial ruin. However, since such decisions are based on data sampling and payroll records, a fully realistic analysis is often not feasible. Under such circumstances, a faulty analysis may lead to faulty decision-making, which in turn affects the business. In recent years, gradually maturing technology and its various applications have allowed researchers to use data about people flow to model real customer behavior. This paper discusses the analysis of this data as it pertains to the execution of a store launch. To test the efficacy of our methods, we will use the data from Feng Chia University as the basis for our analysis and discuss how to use it to determine a suitable location for the school cafeteria.

The thin-film vapor–liquid–solid (TF-VLS) growth technique presents a promising route for high quality, scalable, and cost-effective InP thin films for optoelectronic devices. Toward this goal, careful optimization of material properties and device performance is of utmost interest. Here, we show that exposure of polycrystalline Zn-doped TF-VLS InP to a hydrogen plasma (in the following referred to as hydrogenation) results in improved optoelectronic quality as well as lateral optoelectronic uniformity. A combination of low temperature photoluminescence and transient photocurrent spectroscopy was used to analyze the energy position and relative density of defect states before and after hydrogenation. Notably, hydrogenation reduces the relative intragap defect density by 1 order of magnitude. As a metric to monitor lateral optoelectronic uniformity of polycrystalline TF-VLS InP, photoluminescence and electron beam induced current mapping reveal homogenization of the grain versus grain boundary upon hydroge...

The Si heterojunction (SHJ) solar cell is presently the most popular design in the crystalline Si ( c -Si) photovoltaics due to the high open-circuit voltages ( V OC ). Photon management by surface structuring techniques to control the light entering the devices is critical for boosting cell efficiency although it usually comes with the V OC loss caused by severe surface recombination. For the first time, the periodic inverted pyramid (IP) structure fabricated by photolithography and anisotropic etching processes was employed for SHJ solar cells, demonstrating concurrent improvement in optical and electrical characteristics (i.e., short-circuit current density ( J SC ) and V OC ). Periodic IP structures show superior light-harvesting properties as most of the incident rays bounce three times on the walls of the IPs but only twice between conventional random upright pyramids (UPs). The high minority carrier lifetime of the IP structures after a -Si:H passivation results in an enhanced V OC by 28 mV, showing improved carrier collection efficiency due to the superior passivation of the IP structure over the random UP structures. The superior antireflective (AR) ability and passivation results demonstrate that the IP structure has the potential to replace conventional UP structures to further boost the efficiency in solar cell applications.

Background Meiotic recombination hotspots control the frequency and distribution of Spo11 (Rec12)-initiated recombination in the genome. Recombination occurs within and is regulated in part by chromatin structure, but relatively few of the many chromatin remodeling factors and histone posttranslational modifications (PTMs) have been interrogated for a role in the process. Results We developed a chromatin affinity purification and mass spectrometry-based approach to identify proteins and histone PTMs that regulate recombination hotspots. Small (4.2 kbp) minichromosomes (MiniCs) bearing the fission yeast ade6-M26 hotspot or a basal recombination control were purified approximately 100,000-fold under native conditions from meiosis; then, associated proteins and histone PTMs were identified by mass spectrometry. Proteins and PTMs enriched at the hotspot included known regulators (Atf1, Pcr1, Mst2, Snf22, H3K14ac), validating the approach. The abundance of individual histones varied dynamically during meiotic progression in hotspot versus basal control MiniCs, as did a subset of 34 different histone PTMs, implicating these as potential regulators. Measurements of basal and hotspot recombination in null mutants confirmed that additional, hotspot-enriched proteins are bona fide regulators of hotspot activation within the genome. These chromatin-mediated regulators include histone H2A-H2B and H3-H4 chaperones (Nap1, Hip1/Hir1), subunits of the Ino80 complex (Arp5, Arp8), a DNA helicase/E3 ubiquitin ligase (Rrp2), components of a Swi2/Snf2 family remodeling complex (Swr1, Swc2), and a nucleosome evictor (Fft3/Fun30). Conclusions Overall, our findings indicate that a remarkably diverse collection of chromatin remodeling factors and histone PTMs participate in designating where meiotic recombination occurs in the genome, and they provide new insight into molecular mechanisms of the process. Electronic supplementary material The online version of this article (10.1186/s13072-018-0233-x) contains supplementary material, which is available to authorized users.

The fill factor of perovskite solar cells is considerably lower than that of GaAs and silicon, though they have similar open-circuit voltage (V oc ) deficits. To probe the fill factor loss, we applied the J sc -V oc characterization technique on three different types of perovskite solar cells. Based on the J sc -V oc measurements, we calculated the series resistance at maximum power point under different illumination—and thus injection— levels. We found that the series resistances of all three perovskite solar cells are illumination dependent, unlike silicon solar cells. Further analysis is underway to determine the origin of this phenomenon.

Skyline path planning algorithms are popular location-based services because they can help users find optimal travel routes in a road network based on multiple conditions. At present, many researchers are incorporating these algorithms into evacuation route planning. However, the issue with previous methods was that they could only query the static dimensions of roads, such as road section length or the safety score resulting from a particular amount of rainfall. They could not process dynamic dimensions such as the safety scores of the same route after different amounts of rainfall, which can vary significantly. This study thus proposed a neural network-based skyline evacuation route planning algorithm that can calculate the safety scores of each road section resulting from different rainfalls and identify reasonable evacuation routes. Experiments demonstrate the validity of the proposed approach.

We report the fabrication of monolithic all-perovskite tandem solar cells with a stabilized power conversion efficiency of 19.1% and demonstrate improved thermal, atmospheric, and operational stability of the tin–lead perovskite (FA0.75Cs0.25Sn0.5Pb0.5I3) used as the low gap absorber. To achieve a high matched current density in the two-terminal tandem, we develop a route to fabricate uniform and thick tin–lead perovskites that enable the two-terminal tandem to attain external quantum efficiencies >80% in the near infrared. By post-processing the as-deposited tin–lead perovskite films with methylammonium chloride vapor, we increase grain sizes to over a micron and boost solar cell open circuit voltage and fill factor. Tin–lead perovskite solar cells made by this method exhibit the most stable operation at maximum power under simulated sunlight of any reported small bandgap perovskite solar cell to date. We show that an unencapsulated tin–lead perovskite solar cell maintains its full performance after 150 hours at 85C in air, which is substantially better than has been observed previously. This work identifies strategies for attaining highly efficient all-perovskite tandem solar cells while maintaining thermal and operational stability.

Significance The development of efficient artificial photosynthetic systems, designed to store solar energy in chemical bonds, requires the pairing of stable light-absorbing electrodes for both the oxidative and reductive half-reactions. The development of such systems has been hindered in part by the lack of semiconducting photoanodes that are stable under the conditions required for the production of O 2 (g) from water. We demonstrate herein that a reactively sputtered NiO x layer provides a transparent, antireflective, conductive, chemically stable, inherently catalytic coating that stabilizes many efficient and technologically important semiconducting photoanodes under viable system operating conditions, thereby allowing the use of these materials in an integrated system for the sustainable, direct production of fuels from sunlight.

We present an effective light extraction scheme for GaN-based multi-quantum-well (MQW) light emitting diodes with periodic SiO2 nano-honeycomb arrays fabricated by natural lithography and reactive ion etching. The nano-honeycombs significantly boost light output by providing additional light extraction channels, not only guiding the internal modes into air but also alleviating the sever droop effect at high input power. At the driving current of 400 mA, light output power through the nano-honeycombs is 77.8% higher than that of the bare device. In addition, the output power is particularly enhanced at the diffraction angle around 651, which is attributed to the intensive first order diffraction on the honeycombs. Simulations based on finite-difference time-domain method are also carried out to reveal the field distribution across device interfaces. & 2014 Elsevier Ltd. All rights reserved.

The optimized nanospheres (NSs) are simulated and then employed as light-harvesting nanostructures on Si solar cells (SCs). Uniformly distributed monolayers of NSs effectively suppress the reflection over the broadband region at the incident angles up to 85°, greatly improving the optical absorption of the SCs. The calculation results indicating significant reflection elimination and strong forward scattering agree with those obtained by experimental measurements, where the devices with NSs exhibit improved external quantum efficiencies by 13% at 800 nm and conversion efficiency by 21.6%. This simple, controllable and scalable fabrication of broadband and omnidirectional light-harvesting nanostructures is desired from the standpoint of practical applicability in SCs.

We demonstrated that hierarchical structures combining different scales (i.e., pyramids from 1.5 to 7.5 μm in width on grooves from 40 to 50 μm in diameter) exhibit excellent broadband and omnidirectional light-trapping characteristics. These microscaled hierarchical structures could not only improve light absorption but prevent poor electrical properties typically observed from nanostructures (e.g., ultra-high-density surface defects and nonconformal deposition of following layers, causing low open-circuit voltages and fill factors). The microscaled hierarchical Si heterojunction solar cells fabricated with hydrogenated amorphous Si layers on as-cut Czochralski n-type substrates show a high short-circuit current density of 36.4 mA/cm(2), an open-circuit voltage of 607 mV, and a conversion efficiency of 15.2% due to excellent antireflection and light-scattering characteristics without sacrificing minority carrier lifetimes. Compared to cells with grooved structures, hierarchical heterojunction solar cells exhibit a daily power density enhancement (69%) much higher than the power density enhancement at normal angle of incidence (49%), demonstrating omnidirectional photovoltaic characteristics of hierarchical structures. Such a concept of hierarchical structures simultaneously improving light absorption and photocarrier collection efficiency opens avenues for developing large-area and cost-effective solar energy devices in the industry.

An effective and low-cost front-side anti-reflection (AR) technique has long been sought to enhance the performance of highly efficient photovoltaic devices due to its capability of maximizing the light absorption in photovoltaic devices. In order to achieve high throughput fabrication of nanostructured flexible and anti-reflection films, large-scale, nano-engineered wafer molds were fabricated in this work. Additionally, to gain in-depth understanding of the optical and electrical performance enhancement with AR films on polycrystalline Si solar cells, both theoretical and experimental studies were performed. Intriguingly, the nanocone structures demonstrated an efficient light trapping effect which reduced the surface reflection of a solar cell by 17.7% and therefore enhanced the overall electric output power of photovoltaic devices by 6% at normal light incidence. Notably, the output power improvement is even more significant at a larger light incident angle which is practically meaningful for daily operation of solar panels. The application of the developed AR films is not only limited to crystalline Si solar cells explored here, but also compatible with any types of photovoltaic technology for performance enhancement.

Route planning is one of the most common location-based services today. Conventional route planning algorithms could only consider a single criterion, which cannot meet actual needs. Skyline path queries were therefore proposed for multi-criteria path queries. However, we discovered that most existing skyline path query algorithms are extremely slow, and while such slow speeds may be acceptable to the general public, they are unacceptable for disaster relief. We therefore proposed two means of improvement. Experiment simulations demonstrated the validity of our approach.

An effective light-harvesting scheme for InGaN-based multiple quantum well solar cells is demonstrated using stacking layers of polystyrene nanospheres. Light-harvesting efficiencies on the solar cells covered with varied stacks of nanospheres are evaluated through numerical and experimental methods. The numerical simulation reveals that nanospheres with 3 stacking layers exhibit the most improved optical absorption and haze ratio as compared to those obtained by monolayer nanospheres. The experimental demonstration, agreeing with the theoretical analyses, shows that the application of 3-layer nanospheres improves the conversion efficiency of the solar cell by ~31%.

Surface plasmon resonance was observed to red shift in hexagonal nanohemisphere Ag array covered by double-walled carbon nanotubes. By altering the density of carbon nanotubes, the surface plasmon resonance can be tuned from 563 nm to 586 nm and the light scattering is enhanced in the spectral range from orange to red. This leads to improved performance of amorphous silicon solar cells deposited on top, which yields a short-circuit current density of 14.07 mA/cm2 and a power conversion efficiency of 6.55% under the illumination of AM 1.5G. This carbon nanotubes' density-dependent surface plasmon shift is attributed to the dielectric constant change around the periodic Ag nanostructure, which can be applied to other solar cell materials by fine-tuning the surface plasmon resonance to enhance the absorption at wavelength where the active layer is less absorptive.

A hydrogel sensing film for a real-time and indicator-free detection of Zn2+ is developed by embedding a fluorescent indicator 11,16-bis(phenyl)-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimethene in a hydrogel host poly(2-hydroxyethyl methacrylate). The sensing film shows high stability and selectivity to Zn2+. The sensitivity of the sensing film is increased by fabricating a micron-sized pillar array on the surface of the sensing film to increase the surface area. For Zn2+ concentrations of 10−4 and 10−3 M, the response time is 30 and 3 s, respectively.

Si nanorod arrays (NRAs) mimicking moth-eye structures were fabricated with colloidal lithography and reactive ion etching. Compared with that on polished surface, the reflectance on NRA structures is significantly reduced by more than 10 times. The reflectance is decreased with the height of the NRAs. The anti-reflection (AR) ability of the NRAs is accompanied with broad band, omnidirectional, and polarization-insensitive characteristics. The enhancement of surface hydrophobicity is also observed with increasing height of the NRAs. A detailed experimental analysis of the height-dependent AR and self-cleaning characteristics will benefit the design and optimization processes of Si nanowire-based optoelectronic devices.

Optical resonance formed inside a nanocavity resonator can trap light within the active region and hence enhance light absorption, effectively boosting device or material performance in applications of solar cells, photodetectors (PDs), and photocatalysts. Complementing conventional circular and spherical structures, a new type of multishelled spherical resonant strategy is presented. Due to the resonance-enhanced absorption by multiple convex shells, ZnO nanoshell PDs show improved optoelectronic performance and omnidirectional detection of light at different incidence angles and polarization. In addition, the response and recovery speeds of these devices are improved (0.8 and 0.7 ms, respectively) up to three orders of magnitude faster than in previous reports because of the existence of junction barriers between the nanoshells. The general design principles behind these hollow ZnO nanoshells pave a new way to improve the performance of sophisticated nanophotonic devices.

The non-toxic and wide bandgap material TiO2 is explored as an n-type buffer layer on p-type Cu(In,Ga)Se2 (CIGS) absorber layer for thin film solar cells. The amorphous TiO2 thin film deposited by atomic layer deposition process at low temperatures shows conformal coverage on the CIGS absorber layer. Solar cells from non-vacuum deposited CIGS absorbers with TiO2 buffer layer result in a high short-circuit current density of 38.9 mA/cm2 as compared to 36.9 mA/cm2 measured in the reference cell with CdS buffer layer, without compromising open-circuit voltage. The significant photocurrent gain, mainly in the UV part of the spectrum, can be attributed to the low parasitic absorption loss in the ultrathin TiO2 layer (~10 nm) with a larger bandgap of 3.4 eV compared to 2.4 eV of the traditionally used CdS. Overall the solar cell conversion efficiency was improved from 9.5% to 9.9% by substituting the CdS by TiO2 on an active cell area of 10.5 mm2. Optimized TiO2/CIGS solar cells show excellent long-term stability. The results imply that TiO2 is a promising buffer layer material for CIGS solar cells, avoiding the toxic CdS buffer layer with added performance advantage.

Amorphous Si (a-Si)/crystalline Si (c-Si) heterojunction (SiHJ) can serve as highly efficient and robust photoelectrodes for solar fuel generation. Low carrier recombination in the photoelectrodes leads to high photocurrents and photovoltages. The SiHJ was designed and fabricated into both photoanode and photocathode with high oxygen and hydrogen evolution efficiency, respectively, by simply coating of a thin layer of catalytic materials. The SiHJ photoanode with sol-gel NiOx as the catalyst shows a current density of 21.48 mA/cm(2) at the equilibrium water oxidation potential. The SiHJ photocathode with 2 nm sputter-coated Pt catalyst displays excellent hydrogen evolution performance with an onset potential of 0.640 V and a solar to hydrogen conversion efficiency of 13.26%, which is the highest ever reported for Si-based photocathodes.

When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.