Gap-free X and Y chromosome assemblies of Salix arbutifolia reveal an evolutionary change from male to female heterogamety in willows, without a change in the position of the sex-determining locus.

In the Vetrix clade of Salix, a genus of woody flowering plants, sex determination involves chromosome 15, but an XY system has changed to a ZW system. We studied the detailed genetic changes involved. We used genome sequencing, with chromosome conformation capture (Hi-C) and PacBio HiFi reads to assemble chromosome level gap-free X and Y of Salix arbutifolia, and distinguished the haplotypes in the 15X- and 15Y-linked regions, to study the evolutionary history of the sex-linked regions (SLRs). Our sequencing revealed heteromorphism of the X and Y haplotypes of the SLR, with the X-linked region being considerably larger than the corresponding Y region, mainly due to accumulated repetitive sequences and gene duplications. The phylogenies of single-copy orthogroups within the SLRs indicate that S. arbutifolia and Salix purpurea share an ancestral SLR within a repeat-rich region near the chromosome 15 centromere. During the change in heterogamety, the X-linked region changed to a W-linked one, while the Z was derived from the Y.

Effects of the Insect Growth Regulators Azadirachtin, Pyriproxyfen, and Tebufenozide on the Fatty Acid Metabolome of Bactrocera Dorsalis Larvae.

Insects' lipids, including fatty acids, as the second largest constituents in insects, play a variety of fundamental and vital functions. However, there is a lack of reports on the effects of insect growth regulators on fatty acid profiles and metabolic mechanisms. Therefore, in this study, a comparative study of three growth regulators, azadirachtin, pyriproxyfen, and tebufenozide, on fatty acids was carried out using a targeted metabolomics approach to fill this gap. The results showed that when exposed to azadirachtin, pyriproxyfen, and tebufenozide, there were 14, 17, and 11 differentially regulated fatty acids, respectively. The pathway of biosynthesis of unsaturated fatty acids was the common shared pathway, while fatty acid biosynthesis and linoleic acid metabolism were the specific pathways affected by the 3 insect growth regulators. Therefore, the results could be helpful to deepen the effects of azadirachtin and insect growth regulators on terrestrial insects.

[Species identification of Ligustrum lucidum].

Ligustrum lucidum is a woody perennial plant of genus Ligustrum in family Oleaceae. Its dried fruit has high medicinal value. In this study, the authors evaluated the variability and species identification efficiency of three specific DAN barcodes(rbcL-accD, ycf1a, ycf1b) and four general DAN barcodes(matK, rbcL, trnH-psbA, ITS2) for a rapid and accurate molecular identification of Ligustrum species. The results revealed that matK, rbcL, trnH-psbA, ITS2 and ycf1a were inefficient for identifying the Ligustrum species, and a large number of insertions and deletions were observed in rbcL-accD sequence, which was thus unsuitable for development as specific barcode. The ycf1b-2 barcode had DNA barcoding gap and high success rate of PCR amplification and DNA sequencing, which was the most suitable DNA barcode for L. lucidum identification and achieved an accurate result. In addition, to optimize the DNA extraction experiment, the authors extracted and analyzed the DNA of the exocarp, mesocarp, endocarp and seed of L. lucidum fruit. It was found that seed was the most effective part for DNA extraction, where DNAs of high concentration and quality were obtained, meeting the needs of species identification. In this study, the experimental method for DNA extraction of L. lucidum was optimized, and the seed was determined as the optimal part for DNA extraction and ycf1b-2 was the specific DNA barcode for L. lucidum identification. This study laid a foundation for the market regulation of L. lucidum.

Nano-pesticide carrier O-Carboxymethyl chitosan is indigestible in Apis cerana cerana and affects intestinal flora.

O-Carboxymethyl chitosan nanoparticles (O-CMC-NPs), which are organic pesticide carriers, have excellent application potential. Exploring the effects of O-CMC-NPs on non-target organisms, such as Apis cerana cerana, is critical for their effective application; however, such studies are limited. This study investigated the stress response of A. cerana Fabricius after O-CMC-NPs ingestion. The administration of high O-CMC-NP concentrations enhanced the activities of antioxidant and detoxifying enzymes in A. cerana, with the activity of glutathione-S-transferase increasing by 54.43 %-64.33 % after one day. The transit of O-CMC-NPs into the A. cerana midgut resulted in their deposition and adherence to the intestinal wall, as they cluster and precipitate in acidic conditions. The population of Gillianella bacteria in the middle intestine was remarkably reduced after 6 d of administration of high O-CMC-NP concentrations. Contrastingly, the abundance of Bifidobacteria and Lactobacillus in the rectum significantly increased. These results indicate that the intake of high concentrations of O-CMC-NPs causes a stress response in A. cerana and affects the relative abundance of crucial intestinal flora, which may pose a potential risk to the colony. This implies that even nanomaterials with favorable biocompatibility should be applied reasonably within a specific range to avoid adverse effects on the environment and non-target organisms in the context of large-scale research and promotion of nanomaterials.

Evolutionary origin and establishment of a dioecious diploid-tetraploid complex.

Polyploids recurrently emerge in angiosperms, but most polyploids are likely to go extinct before establishment due to minority cytotype exclusion, which may be specifically a constraint for dioecious plants. Here we test the hypothesis that a stable sex-determination system and spatial/ecological isolation facilitate the establishment of dioecious polyploids. We determined the ploidy levels of 351 individuals from 28 populations of the dioecious species Salix polyclona, and resequenced 190 individuals of S. polyclona and related taxa for genomic diversity analyses. The ploidy survey revealed a frequency 52% of tetraploids in S. polyclona, and genomic k-mer spectra analyses suggested an autopolyploid origin for them. Comparisons of diploid male and female genomes identified a female heterogametic sex-determining factor on chromosome 15, which probably also acts in the dioecious tetraploids. Phylogenetic analyses revealed two diploid clades and a separate clade/grade of tetraploids with a distinct geographic distribution confined to western and central China, where complex mountain systems create higher levels of environmental heterogeneity. Fossil-calibrated phylogenies showed that the polyploids emerged during 7.6-2.3 million years ago, and population demographic histories largely matched the geological and climatic history of the region. Our results suggest that inheritance of the sex-determining system from the diploid progenitor as intrinsic factor and spatial isolation as extrinsic factor may have facilitated the preservation and establishment of polyploid dioecious populations.

[Spatial Differentiation and Influencing Factor Analysis of Soil Heavy Metal Content at Town Level Based on Geographic Detector].

Geographic detectors can quickly detect spatial stratified heterogeneity and quantitatively reveal the intensity of driving factors of heavy metal content, which is of great significance for the prevention, control, and remediation of soil heavy metal pollution. In order to reveal the spatial differentiation and influencing factors of soil heavy metal content on the town-scale, 788 topsoil samples were collected from a town in the hinterland of Chengdu Plain. Soil heavy metal (Cd, Hg, As, Cu, Pb, Cr, Zn, and Ni) pollution risk assessments were carried out by using the geo-accumulation index method. Additionally, based on the geographic detector model, 15 factors such as soil properties, topography, soil forming factors, and distance were taken as independent variables, and the contents of each heavy metal element were taken as dependent variables to explore the spatial differentiation and influencing factors of heavy metal content in soils. The results showed that:the average contents of Hg, As, Pb, Cr, Cu, Ni, and Zn in the study area were 1.06-1.93 times the background value of Chengdu, and the content of Cd was lower than the background value; among them, Hg reached the light pollution level, and the other seven heavy metals were at the non-pollution level. The spatial distribution of eight heavy metals was significantly different, the correlation among the elements was significant, and a significant correlation was found between most heavy meals with soil properties; however, the correlation with distance factor and topographic factor was relatively weak. The factor detection showed that TP, TK, pH, TOC, elevation, and distance from the railway had the most significant explanatory power for the heavy metal contents. Interaction detection showed that the interaction between soil properties and other factors was the dominant factor for the spatial variation in heavy metals, and elevation, distance from residential area, distance from railways, and distance from industrial areas were also important factors. Risk detection showed that Hg had the most significant difference in the subregion of elevation and distance from railway, whereas the other seven heavy metals had the most significant difference in the sub-regions of influencing factors of soil properties. The spatial distribution of heavy metals varied significantly in soil at the town-scale, which was closely related to soil properties, topography, and human activities in the study area.

Effects of Atmospheric Pressure Plasma in the Treatment of Experimental Periodontitis in Beagle Dogs.

OBJECTIVE: The specific objective of this study was to evaluate the effects of atmospheric pressure plasma (APP) in the treatment of experimental periodontitis in Beagle dogs. METHODS: The APP jet was diagnosed using optical emission spectroscopy and laser-induced fluorescence spectroscopy. Six Beagles received stainless steel ligatures to establish experimental periodontitis model. The teeth in the control group were subjected to conventional root surface debridement (RSD) and chlorhexidine irrigation. The APP group also started with RSD and was then subjected to plasma irradiation. Clinical analyses including plaque index, modified sulcus bleeding index, pocket depth and attachment loss (AL), as well as cone-beam computed tomography (CBCT) analysis, were performed at baseline, 4th week, 8th week and 12th week after treatment. RESULTS: The results showed that typical reactive oxygen and nitrogen species were found in the full spectrum and the gas temperature of APP was close to room temperature. The highest concentrations of hydroxide and oxygen were obtained at 5 mm away from the nozzle. In both groups, all values in clinical examinations were significantly lower (P<0.05) at 12th week after treatment than those at baseline. At the 12th week, the AL in clinical examinations and the bone loss in CBCT images in the APP group were significantly lower than those in the control group (P<0.05). The hematoxylin-eosin staining showed more renascent alveolar bone in the APP group than in the control group. CONCLUSION: These findings suggested that APP has profound potential for use as an adjunct approach for periodontitis treatment.

Recent advances on phylogenomics of gymnosperms and a new classification.

Living gymnosperms comprise four major groups: cycads, Ginkgo, conifers, and gnetophytes. Relationships among/within these lineages have not been fully resolved. Next generation sequencing has made available a large number of sequences, including both plastomes and single-copy nuclear genes, for reconstruction of solid phylogenetic trees. Recent advances in gymnosperm phylogenomic studies have updated our knowledge of gymnosperm systematics. Here, we review major advances of gymnosperm phylogeny over the past 10 years and propose an updated classification of extant gymnosperms. This new classification includes three classes (Cycadopsida, Ginkgoopsida, and Pinopsida), five subclasses (Cycadidae, Ginkgoidae, Cupressidae, Pinidae, and Gnetidae), eight orders (Cycadales, Ginkgoales, Araucariales, Cupressales, Pinales, Ephedrales, Gnetales, and Welwitschiales), 13 families, and 86 genera. We also described six new tribes including Acmopyleae Y. Yang, Austrocedreae Y. Yang, Chamaecyparideae Y. Yang, Microcachrydeae Y. Yang, Papuacedreae Y. Yang, and Prumnopityeae Y. Yang, and made 27 new combinations in the genus Sabina.

Reproductive biology of an endangered lithophytic shrub and implications for its conservation.

BACKGROUND: Plants in cliff habitats may evolve specific reproductive strategies to cope with harsh environments, and unraveling these reproductive characteristics can improve our understanding of survival strategies and lithophyte evolution. This understanding is especially important for efforts to protect rare and endemic plants. Here, we investigated the reproductive biology of Lonicera oblata, an endangered lithophytic shrub that is scattered in highly fragmented and isolated cliff habitats of the Taihang and Yan mountains in North China. RESULTS: Flowers of L. oblata are herkogamous and protandrous, characteristics that can prevent autogamy at the single-flower level, and insects are necessary for pollination. The outcrossing index, pollen/ovule ratio, and the results of hand pollination were measured and all revealed a mixed mating system for L. oblata, that combines cross-fertilization and partial self-fertilization. The floral traits of L. oblata of zygomorphic and brightly yellowish corolla, heavy fragrance, and rich nectar, suggest an entomophilous pollination system. Sweat bees were observed as the most effective pollinators but their visiting frequencies were not high. Pollen limitation may limit the reproductive success of L. oblata. CONCLUSIONS: We determined the reproductive characteristics of L. oblata, a critically endangered species endemic to cliffs in North China, providing insight into its endangerment and suggesting conservation strategies. L. oblata has highly pollinator-dependent self-fertilization as part of a mixed mating system. Floral features such as low-flowering synchrony, asynchronous anthers dehiscence, and high duration of stigma receptivity, improve pollination efficiency in the case of low pollinator service. Our work provides reference information to understand the survival strategies and conservation of L. oblata and other lithophytes.

The phylogeny of Salix revealed by whole genome re-sequencing suggests different sex-determination systems in major groups of the genus.

BACKGROUND AND AIMS: The largest genus of Salicaceae sensu lato, Salix, has been shown to consist of two main clades: clade Salix, in which species have XY sex-determination systems (SDSs) on chromosome 7, and clade Vetrix including species with ZW SDSs on chromosome 15. Here, we test the utility of whole genome re-sequencing (WGR) for phylogenomic reconstructions of willows to infer changes between different SDSs. METHODS: We used more than 1 TB of WGR data from 70 Salix taxa to ascertain single nucleotide polymorphisms on the autosomes, the sex-linked regions (SLRs) and the chloroplast genomes, for phylogenetic and species tree analyses. To avoid bias, we chose reference genomes from both groups, Salix dunnii from clade Salix and S. purpurea from clade Vetrix. KEY RESULTS: Two main largely congruent groups were recovered: the paraphyletic Salix grade and the Vetrix clade. The autosome dataset trees resolved four subclades (C1-C4) in Vetrix. C1 and C2 comprise species from the Hengduan Mountains and adjacent areas and from Eurasia, respectively. Section Longifoliae (C3) grouped within the Vetrix clade but fell into the Salix clade in trees based on the chloroplast dataset analysis. Salix triandra from Eurasia (C4) was revealed as sister to the remaining species of clade Vetrix. In Salix, the polyploid group C5 is paraphyletic to clade Vetrix and subclade C6 is consistent with Argus's subgenus Protitea. Chloroplast datasets separated both Vetrix and Salix as monophyletic, and yielded C5 embedded within Salix. Using only diploid species, both the SLR and autosomal datasets yielded trees with Vetrix and Salix as well-supported clades. CONCLUSION: WGR data are useful for phylogenomic analyses of willows. The different SDSs may contribute to the isolation of the two major groups, but the reproductive barrier between them needs to be studied.

Leaky Mode Resonance-Induced Sensitive Ultraviolet Photodetector Composed of Graphene/Small Diameter Silicon Nanowire Array Heterojunctions.

Ultraviolet photodetectors (UVPDs) based on wide band gap semiconductors (WBSs) are important for various civil and military applications. However, the relatively harsh preparation conditions and the high cost are unfavorable for commercialization. In this work, we proposed a non-WBS UVPD by using a silicon nanowire (SiNW) array with a diameter of 45 nm as building blocks. Device analysis revealed that the small diameter SiNW array covered with monolayer graphene was sensitive to UV light but insensitive to both visible and infrared light illumination, with a typical rejection ratio of 25. Specifically, the responsivity, specific detectivity, and external quantum efficiency under 365 nm illumination were estimated to be 0.151 A/W, 1.37 × 1012 Jones, and 62%, respectively, which are comparable to or even better than other WBS UVPDs. Such an abnormal photoelectrical characteristic is related to the HE1m leaky mode resonance (LMR), which is able to shift the peak absorption spectrum from near-infrared to UV regions. It is also revealed that this LMR is highly dependent on the diameter and the period of the SiNW array. These results show narrow band gap semiconductor nanostructures as promising building blocks for the assembly of sensitive UV photodetectors, which are very important for various optoelectronic devices and systems.

Filterless Discrimination of Wavelengths in the Range from Ultraviolet to Near-Infrared Light Using Two PdSe2/Thin Si/PdSe2 Heterojunction Photodetectors.

In this study, we present a wavelength sensor that is capable of distinguishing the spectrum in the range from ultraviolet (UV) to near-infrared (NIR) light. The filterless device is composed of two horizontally stacking PdSe2/20 µm Si/PdSe2 heterojunction photodetectors with a photovoltaic (PV) behavior, which makes it possible for the device to work at 0 bias voltage. Due to the relatively small thickness of Si and the wavelength-dependent absorption coefficient, the two PdSe2/20 µm Si/PdSe2 photodetectors according to theoretical simulation display a sharp contrast in distribution of the photoabsorption rate. As a result, the photocurrents of both photodetectors evolve in completely different ways with increasing wavelengths, leading to a monotonic decrease in the photocurrent ratio from 6800 to 22 when the wavelength gradually increases from 265 to 1050 nm. The corresponding relationship between both the photocurrent ratio and wavelength can be easily described by the monotonic function, which can help to precisely determine the wavelength in the range from 265 to 1050 nm, with an average relative error less than ±1.6%. It is also revealed that by slightly revising the monotonic function, the wavelength in other different temperatures can also be estimated.

Complete chloroplast genome sequence of Procris crenata C.B.Rob (Urticaceae).

The complete chloroplast (cp) genome of Procris crenata C.B.Rob was reported. The cp genome was 154,124 bp in length and contained two inverted repeats (IRs) of 25,626 bp, which were separated by large single-copy and small single-copy of 84,599 bp and 18,273 bp, respectively. The GC content was 36.5%. A total of 113 functional genes were encoded, comprising 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. This is the first reported plastid genome in Procris (Urticaceae), which will be useful data for resolving the relationship within the family.

Computational Studies on the Materials Combining Graphene Quantum Dots and Pt Complexes with Adjustable Luminescence Characteristics.

Graphene materials with particular properties are proved to be beneficial to photoelectric devices, but there are rare reports on a positive effect by graphene on emissive layer materials of organic light-emitting diodes (OLEDs) previously. On the basis of the latest important experiments, an OLED device with the aid of graphene quantum dots shows the dawn of their application for luminescent materials. The luminescence performance has been improved, but the understanding of the internal excited-state radiation mechanism of the material needs further study. In this work, the Pt(II)-coordinated graphene quantum dot coplanar structures with different shapes are studied theoretically in detail, and the results present the improvement in phosphorescence under the promoted radiative decay and suppressed nonradiative decay. This composite combines the advantages of transition metal complexes and graphene quantum dots and also exhibits excellent properties in the light absorption region and carrier transportation for the OLED. This comprehensive theoretical calculation research can provide a comprehensive basis of the material design in the future.

Direct Tellurization of Pt to Synthesize 2D PtTe2 for High-Performance Broadband Photodetectors and NIR Image Sensors.

Platinum telluride (PtTe2) has garnered significant research enthusiasm owing to its unique characteristics. However, large-scale synthesis of PtTe2 toward potential photoelectric and photovoltaic application has not been explored yet. Herein, we report direct tellurization of Pt nanofilms to synthesize large-area PtTe2 films and the influence of growth conditions on the morphology of PtTe2. Electrical analysis reveals that the as-grown PtTe2 films exhibit typical semimetallic behavior, which is in agreement with the results of first-principles density functional theory (DFT) simulation. Moreover, the combination of multilayered PtTe2 and Si results in the formation of a PtTe2/Si heterojunction, exhibiting an obvious rectifying effect. Moreover, the PtTe2-based photodetector displays a broadband photoresponse to incident radiation in the range of 200-1650 nm, with the maximum photoresponse at a wavelength of ∼980 nm. The R and D* of the PtTe2-based photodetector are found to be 0.406 A W-1 and 3.62 × 1012 Jones, respectively. In addition, the external quantum efficiency is as high as 32.1%. On the other hand, the response time of τrise and τfall is estimated to be 7.51 and 36.7 µs, respectively. Finally, an image sensor composed of a 8 × 8 PtTe2-based photodetector array was fabricated, which can record five near-infrared (NIR) images under 980 nm with a satisfying resolution. The result demonstrates that the as-prepared PtTe2 material will be useful for application in NIR optoelectronics.

Eco-Friendly Castor Oil-Based Delivery System with Sustained Pesticide Release and Enhanced Retention.

The deposition of pesticides and their retention on plant surfaces are critical challenges for modern precision agriculture, which directly affect phytosanitary treatment, bioavailability, efficacy, and the loss of pesticides. Herein, a novel and eco-friendly waterborne polyurethane delivery system was developed to enhance the spray deposition and pesticide retention on plant surfaces. More specifically, biobased cationic and anionic waterborne polyurethane dispersions were synthesized from castor oil. Both cationic and anionic polyurethane dispersions exhibited remarkable microstructural, amphiphilic, and nanoparticle morphologies with a core-shell structure that served to encapsulate a biopesticide (azadirachtin) in their hydrophobic cores (WPU-ACT). The results indicated that the cationic WPU-ACT carriers exhibited a better sustained release behavior and a better protective effect from light and heat for azadirachtin. In addition, the simultaneous spray of anionic and cationic WPU-ACT significantly enhanced the spray deposition and prolonged the retention of pesticides due to the reduced surface tension and surface precipitation induced by the electrostatic interaction when two droplets with opposite charges come into contact with each other. A field efficacy assessment also indicated that the simultaneous spray of anionic and cationic WPU-ACT could control the infestation of brown planthopper in rice crops. Castor oil-based waterborne polyurethanes in this study work as an efficient pesticide delivery system by exhibiting enhanced deposition, rainfastness, retention ability, protection, and sustained release behavior, holding great promise for spraying pesticide formulations in modern and environmentally friendly agricultural applications.

Integrated LC-MS and GC-MS-based untargeted metabolomics studies of the effect of azadirachtin on Bactrocera dorsalis larvae.

Azadirachtin exhibits excellent bioactivities against several hundred arthropods. However, current knowlege of its biochemical effect on B. dorsalis larvae is not deep enough. In this study, integrated LC-MS and GC-MS-based untargeted metabolomics were used to analyze the changes of endogenous metabolites and the biochemical effects of azadirachtin on B. dorsalis larvae. Azadirachtin has excellent bioactivities against B. dorsalis larvae in this study, leading to a longer developmental duration, lower survival rate, and low pupa weight. The effect of azadirachtin was investigated on a total of 22 and 13 differentially abundant metabolites in the LC-MS and GC-MS-based metabolomics results, are selected respectively. Pathway analysis indicated that 14 differentially enriched metabolic pathways, including seven influential pathways, are worthy of attention. Further integrated key metabolic pathway analysis showed that histidine metabolism, D-glutamine and D-glutamate metabolism, biotin metabolism, ascorbate and aldarate metabolism, pentose and glucuronate interconversions, and alanine, aspartate and glutamate metabolism in B. dorsalis larvae are significantly relevant pathways affected by azadirachtin. Although extrapolating the bioactivity results in this study to the practical project of B. dorsalis pest management in the field has limitations, it was found that azadirachtin has a significant effect on the primary metabolism of B. dorsalis larvae.

The comparative metabolic response of Bactrocera dorsalis larvae to azadirachtin, pyriproxyfen and tebufenozide.

Azadirachtin, as the most promising and effective botanical insecticide, exhibits significant growth inhibition activity against agricultural and forestry pests. However, its biochemical effects at the metabolic level compared with those of other insect growth regulators have not been studied. Therefore, in this study, a GC-MS based untargeted metabolomics approach was applied to compare azadirachtin with pyriproxyfen (a juvenile hormone analog) and tebufenozide (a molting hormone analog) in terms of their metabolic effects on Bactrocera dorsalis larvae. The bioactivity of azadirachtin against B. dorsalis larvae was significantly different than those of pyriproxyfen and tebufenozide. A total of 693 mass features were recognized, and 112 metabolites were identified in this study. The results showed that a total of 16, 13 and 10 differentially regulated metabolites corresponding to 12, 5 and 8 pathways occur in Aza versus CK, Pyr versus CK and Teb versus CK group, respectively. Further analysis showed that 6 differentially regulated metabolites corresponding to 5 key pathways could be the primary differential metabolic response of B. dorsalis larvae to the three insect growth regulators. The pathways were myo-inositol corresponding to ascorbate and aldarate metabolism as the specific response of B. dorsalis larvae to azadirachtin; xylitol, xylulose and 3-aminopropionitrile corresponding to pentose and glucuronate interconversions, and cyanoamino acid metabolism as the common responses to azadirachtin and pyriproxyfen; and 3-hydroxypropionic acid and beta-alanine corresponding to propanoate metabolism and beta-alanine metabolism as the specific responses to tebufenozide. The results showed that the metabolic response of B. dorsalis larvae to azadirachitin is closer to that of pyriproxyfen than tebufenozide. The differentially regulated metabolites and pathways responsible for this difference are discussed.

Ultrathin Polymer Nanofibrils for Solar-Blind Deep Ultraviolet Light Photodetectors Application.

Solar-blind deep ultraviolet photodetectors (DUVPDs) based on conventional inorganic ultrawide bandgap semiconductors (UWBS) have shown promising application in various civil and military fields and yet they can hardly be used in wearable optoelectronic devices and systems for lack of mechanical flexibility. In this study, we report a non-UWBS solar-blind DUVPD by designing ultrathin polymer nanofibrils with a virtual ultrawide bandgap, which was obtained by grafting P3HT with PHA via a polymerization process. Optoelectronic analysis reveals that the P3HT-b-PHA nanofibrils are sensitive to DUV light with a wavelength of 254 nm but are virtually blind to both 365 nm and other visible light illuminations. The responsivity is 120 A/W with an external quantum efficiency of up to 49700%, implying a large photoconductive gain in the photoresponse process. The observed solar-blind DUV photoresponse is associated with the resonant mode due to the leakage mode of the ultrathin polymer nanofibrils. Moreover, a flexible image sensor composed of 10 × 10 pixels can also be fabricated to illustrate their capability for image sensing application. These results signify that the present ultrathin P3HT-b-PHA nanofibrils are promising building blocks for assembly of low-cost, flexible, and high-performance solar-blind DUVPDs.

Multilayered PdSe2/Perovskite Schottky Junction for Fast, Self-Powered, Polarization-Sensitive, Broadband Photodetectors, and Image Sensor Application.

Group-10 transition metal dichalcogenides (TMDs) with distinct optical and tunable electrical properties have exhibited great potential for various optoelectronic applications. Herein, a self-powered photodetector is developed with broadband response ranging from deep ultraviolet to near-infrared by combining FA1- x Cs x PbI3 perovskite with PdSe2 layer, a newly discovered TMDs material. Optoelectronic characterization reveals that the as-assembled PdSe2/perovskite Schottky junction is sensitive to light illumination ranging from 200 to 1550 nm, with the highest sensitivity centered at ≈800 nm. The device also shows a large on/off ratio of ≈104, a high responsivity (R) of 313 mA W-1, a decent specific detectivity (D*) of ≈1013 Jones, and a rapid response speed of 3.5/4 µs. These figures of merit are comparable with or much better than most of the previously reported perovskite detectors. In addition, the PdSe2/perovskite device exhibits obvious sensitivity to polarized light, with a polarization sensitivity of 6.04. Finally, the PdSe2/perovskite detector can readily record five "P," "O," "L," "Y," and "U" images sequentially produced by 808 nm. These results suggest that the present PdSe2/perovskite Schottky junction photodetectors may be useful for assembly of optoelectronic system applications in near future.