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The development of natural polymer-based hydrogels, combining outstanding injectability, self-healing, and tissue adhesion, with mechanical performance, able to facilitate full-thickness skin wound healing, remains challenging. We have developed an injectable micellar hydrogel (AF127/HA-ADH/OHA-Dop) with outstanding adhesive and self-healing properties able to accelerate full-thickness skin wound healing. Dopamine-functionalized oxidized hyaluronic acid (OHA-Dop), adipic acid dihydrazide-modified HA (HA-ADH), and aldehyde-terminated Pluronic F127 (AF127) were employed as polymer backbones. They were cross-linked in situ using Schiff base dynamic covalent bonds (AF127 micelle/HA-ADH network and HA-ADH/OHA-Dop network), hydrogen bonding, and π-π stacking interactions. The resulting multicross-linked double-network design forms a micellar hydrogel. The unique multicross-linked double-network structure endows the hydrogel with both improved injection abilities and mechanical performance while self-healing faster than single-network hydrogels. Inspired by mussel foot adhesive protein, OHA-Dop mimics the catechol groups seen in mussel proteins, endowing hydrogels with robust adhesion properties. We also demonstrate the potential of our hydrogels to accelerate full-thickness cutaneous wound closure and improve skin regeneration with reduced scarring. We anticipate that our hydrogel platform based on a novel multicross-linked double-network design will transform the future development of multifunctional wound dressings.

In the field of nuclear medical imaging, nuclear and particle physics electronics, precise time measurement is an important task. In this paper, we focused on a real-time interpolated timing algorithm based on waveform digitization, which can be integrated in a field-programmable gate array (FPGA) device. The basic principle of this algorithm is to calculate the pulse peak and the time point when the pulse crosses the threshold. We analyzed the factors that would influence the time precision, and conducted simulations to estimate the effect. After implementing the algorithm in the FPGA, tests were conducted with the results concording well with the simulation, and a time precision of around 3 ps is successfully achieved for the photomultiplier tubes (PMT)-like pulse digitized by 800 MSps 12-bit analog-to-digital converter (ADC).

Eutrophication of lakes is one of the most common pressures affecting aquatic biodiversity and ecosystem services. Poyang Lake is of great importance for maintaining regional ecological balance; however, algal blooms have become major environmental problems in this basin, and they are also caused by a variety of problems including biodiversity decline, toxin production and possibly unsafe drinking water. In this study, the community structure of phytoplankton and physicochemical parameters were investigated in different eutrophication area, Poyang Lake Basin. The results showed that the number of phytoplankton species had decreased, but the density and biomass were increased in the current period. The assemblage structure of phytoplankton showed significantly seasonal and spatial variability. The assemblage structure of phytoplankton was related to dissolved oxygen, nitrate nitrogen, chlorophyll-a and ammonium nitrogen, based on redundancy analysis. The study showed that the phytoplankton community structure was influenced by algal blooms and water quality factors. This study provides an important reference for increased biomonitoring and ecohydrological studies in this basin.

Poyang Lake Basin is of great importance to maintain regional ecological balance. However, fish biodiversity in this basin has rapidly declined as the result of anthropogenic habitat alteration, such as dam construction, sand mining, and water pollution. Here, we aimed to analyze the temporal and spatial changes in biodiversity patterns of fish in Poyang Lake Basin over the last 37 years. The number of fish species underwent a significant decrease in the current period. In particular, 36.7% of the migration of fish was extirpated. Twenty‐seven fish species have been formally assessed using the Chinese Red List were currently listed as Critically Endangered (9), Endangered (3), Vulnerable (10), and Near Threatened (5). Alpha and gamma diversity revealed that fish diversity had also decreased, and beta diversity showed significant composition dissimilarity in two periods. PCoA showed that the historical fish composition dissimilarity was significantly different from that of the current period. We found a significant effect of the geographical distance on the spatial turnover component for the historical and current periods. In addition, the nestedness component was the main contributor to beta diversity, which indicated one large protected area should be established in Poyang Lake and the Ganjiang River Basin with higher species richness. These results indicated that fish biodiversity declined in the current period likely caused by anthropogenic habitat alteration and other threatened factors. Therefore, we suggest that the habitat reconstruction and biodiversity conservation for fish have become imperative in this basin, and a complete management plan should be carried out., Poyang Lake Basin is of great importance to maintain regional ecological balance. However, fish diversity in this basin has rapidly declined as the result of human activities. Here, we aimed to analyze how temporal and spatial changes impact biodiversity patterns of the fish assemblages in Poyang Lake Basin over the last 37 years. The diversity of fish species underwent a significant decrease. In particular, 36.7% of the migration of fish was extirpated. Twenty‐seven fish species have been formally assessed using the Chinese Red List were currently listed as Critically Endangered (9), Endangered (3), Vulnerable (10), and Near Threatened (5). Alpha and gamma diversity revealed that fish diversity had also decreased, and beta diversity showed a significant trend toward taxonomic homogenization. PCoA showed that the historical fish composition similarity was significantly different from that of the current period. These results indicated that human activities have seriously affected the fish habitat and led to the decline in fish diversity.

Jiangxi Province is a biodiversity hotspot in the People’s Republic of China and has abundant land-snail species (247). Beta diversity is a key concept for understanding the functioning of ecosystems, the conservation of biodiversity, and the management of ecosystems. Here, the pattern of beta diversity for land snails in Jiangxi Province was analyzed. The results showed that the spatial turnover component was the main contributor to beta diversity, indicating that additional conservation efforts must target an increase in the number of protected areas, which should be spread across each one of the areas, to maximize the protection of species diversity. The nestedness component of diversity was always low, but there was a marked difference between microsnails, in which zero values occurred in 41.3% of all cases, and macrosnails, in which zero values occurred in only 2.7% of cases. There was a difference in the pattern of beta diversity between the two. The principal coordinate analysis showed a clear pattern with four groups in Jiangxi Province. In addition, we found significant effects of precipitation and altitude on overall beta diversity. These results will provide important basic information for the conservation of biodiversity in land snails.

A novel time calibration method for waveform sampling application specific integrated circuits (ASICs) based on switched capacitor arrays (SCAs) is proposed in this paper. Precision timing extraction using SCA ASICs has been proved to be a promising technique in many high energy physics experiments. However, such ASICs suffer from irregular sampling intervals caused by process variations. Therefore, careful calibration is required to improve the time resolution of such systems. We evaluated the limitation of a popular method using the proportionality between voltage amplitude and sampling interval of adjacent switched-capacitor cells responding to either a sawtooth wave or a sine wave . The new time calibration method presented here utilizes the relationship between sampling intervals and the known input signal period to establish overdetermined linear equations, and the roots of these equations correspond to the actual sampling intervals. We applied this new method to a pulse timing test with an ASIC designed by our team, and the test results indicate that the new time calibration method is effective.

Intrinsic degradation in 100 nm AlQ3 OLED device with strong luminescence was observed while nearly no degradation in 50 nm AlQ3 device with weak luminescence was observed for the same operation time. Based on the EL and PL measurements, it was suggested that penetration of AlQ3 molecules into NPB layer resulted in the increase of electron leakage current, and thus significant loss of current efficiency. A plausible Coulomb effect induced intrinsic degradation mechanism was therefore proposed to explain the experimental results.

The time-interleaved analog-to-digital conversion (TIADC) technique is an effective method for increasing the sampling rate in a waveform digitization system. In this study, a 20-Gsps TIADC system was designed. A wide-bandwidth performance was achieved by optimizing the analog circuits, and a sufficient effective number of bits (ENOB) performance guaranteed using the perfect reconstruction algorithm for mismatch error correction. The proposed system was verified by tests, and the results indicated that a − 3 dB bandwidth of 6 GHz and the ENOB performance of 8.7 bits at 1 GHz and 7.6 bits at 6 GHz were successfully achieved.

Metal halide perovskites have shown rapid development in various fields such as photovoltaics, photodetectors, light-emitting diodes (LEDs), and optically pumped lasers owing to their superior optoelectronic properties. Here, we review the basic optoelectronic properties of halide perovskites from a photophysical perspective. We highlight that halide perovskites are promising in various optoelectronic devices functioning at a wide range of carrier densities. We discuss optically and electrically generated carrier density under two different excitation modes [continuous wave (CW) and pulsed] as well as the impact of carrier density on the optoelectronic behavior of perovskites. Moreover, we discuss lasing actions at high carrier densities and summarize key rules to evaluate the lasing actions. Last, we provide an outlook on perovskite-based electrically pumped lasers. Funding Agencies|ERC Starting GrantEuropean Research Council (ERC) [717026]; Swedish Energy Agency EnergimyndighetenSwedish Energy Agency [48758-1, 44651-1]; Swedish Foundation for International Cooperation in Research and Higher Education [CH2018-7736]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]

Bandgap tuning through mixing halide anions is one of the most attractive features for metal halide perovskites. However, mixed halide perovskites usually suffer from phase segregation under electrical biases. Herein, we obtain high-performance and color-stable blue perovskite LEDs (PeLEDs) based on mixed bromide/ chloride three-dimensional (3D) structures. We demonstrate that the color instability of CsPb(Br1-xClx)(3) PeLEDs results from surface defects at perovskite grain boundaries. By effective defect passivation, we achieve color-stable blue electroluminescence from CsPb(Br1-xClx)(3) PeLEDs, with maximum external quantum efficiencies of up to 4.5% and high luminance of up to 5351 cd m(-2) in the sky-blue region (489 nm). Our work provides new insights into the color instability issue of mixed halide perovskites and can spur new development of high-performance and color-stable blue PeLEDs. Funding Agencies|ERC Starting GrantEuropean Research Council (ERC) [717026]; Swedish Energy Agency EnergimyndighetenSwedish Energy Agency [48758-1, 44651-1]; Swedish Foundation for International Cooperation in Research and Higher Education [CH2018-7736]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [200900971]; China Scholarship CouncilChina Scholarship Council

Understanding the feasibility to couple semiconducting and magnetic properties in metal halide perovskites through interface design opens new opportunities for creating the next generation spin‐related optoelectronics. In this work, a fundamentally new phenomenon of optically induced magnetization achieved by coupling photoexcited orbital magnetic dipoles with magnetic spins at perovskite/ferromagnetic interface is discovered. The depth‐sensitive polarized neutron reflectometry combined with in situ photoexcitation setup, constitutes key evidence of this novel effect. It is demonstrated that a circularly polarized photoexcitation induces a stable magnetization signal within the depth up to 7.5 nm into the surface of high‐quality perovskite (MAPbBr3) film underneath a ferromagnetic cobalt layer at room temperature. In contrast, a linearly polarized light does not induce any detectable magnetization in the MAPbBr3. The observation reveals that photoexcited orbital magnetic dipoles at the surface of perovskite are coupled with the spins of the ferromagnetic atoms at the interface, leading to an optically induced magnetization within the perovskite’s surface. The finding demonstrates that perovskite semiconductor can be bridged with magnetism through optically controllable method at room temperature in this heterojunction design. This provides the new concept of utilizing spin and orbital degrees of freedom in new‐generation spin‐related optoelectronic devices., The depth‐sensitive polarized neutron reflectometry technique reveals the optically induced static magnetization in metal halide perovskite by coupling photoexcited orbital magnetic dipoles with spins at perovskite/ferromagnetic interface. This work demonstrates that perovskite can be bridged with magnetism through optically controllable method in perovskite/ferromagnetic heterojunction, providing the new concept of utilizing spin and orbital degrees of freedom for spin‐related optoelectronics.

Positron Emission Tomography (PET) is an important research direction in the field of nuclear medicine. We designed the Single Processing Unit (SPU) electronics for a brain PET system, which is based on the Time-of-Flight (TOF) PET structure. The SPU electronics are required to achieve a 5%0 energy measurement precision as well as a 50-ps-FWHM time measurement precision. The readout electronics include analog front end amplification, shaping, A/D conversion, and time measurement circuits, as well as digital signal processing logic based on a Field Programmable Logic Gate Array (FPGA). Besides, to relieve the data processing pressure of the Coincidence Process Unit (CPU), we designed a single data frame sorting algorithm based on a token ring structure and swap sorting method. The algorithm guarantees that the single data frames are arranged according to their time information. A data frame packaging algorithm is also implemented to ensure the data frames with the time information within a predetermined period are packaged into data frame packages. We conducted tests on the electronics, and the results showed successful time measurement performance while the single data frame sorting algorithm and the data packaging logic functioned well.

High speed waveform digitization is one of the methods that can be applied to time measurement. In our previous work, a 5-Gsps switched capacitor array (SCA) chip for high-precision time measurement was designed. In this paper, this SCA ASIC is tested, and the effects of mismatches between sampling cells inside the ASIC are analyzed. The test results show that after the calibration and mismatch correction processes, a time resolution of better than 10ps can be successfully achieved.

Doping has been used as a common method to improve photovoltaic performance in perovskite solar cells (PSCs). This paper reports a new phenomenon that the SnF2 doping can largely increase the exciton-exciton interaction through orbital magnetic dipoles toward increasing dissociation probabilities in lead-free FASnI2Br PSCs. Essentially, when orbit-orbit interaction between excitons occurs, linearly and circularly polarized photoexcitations can inevitably generate different photocurrents, giving rise to a ΔJsc phenomenon. Here, it is found that, when SnF2 doping is used to boost photovoltaic efficiency to 7.61%, the orbit-orbit interaction is increased by a factor of 2.2, shown as the ΔJsc changed from 1.21% to 0.55%. Simultaneously, magnetic field effects of Jsc indicate that increasing orbit-orbit interaction leads to an increase on the spin-orbital coupling in Sn perovskites (FASnI2Br) upon SnF2 doping. This presents a new doping effect occurring in the Sn perovskite solar cell toward enhancing photovoltaic efficiency.

The Yangtze River is a biodiversity hotspot, and it has the most diverse fish assemblages on Earth. Dam construction is one of the main causes of fish biodiversity decline. The Three Gorges Dam (TGD) is the world’s largest hydroelectric dam, which is a cause of concern for ecologists worldwide, mainly regarding the negative impacts on biodiversity and the ecological processes in the region. Information on the biodiversity patterns of fish is vital for informing conservation and management strategies. However, few studies have articulated the principal mechanisms underlying the interactions between the biodiversity patterns of fish and anthropogenic habitat alterations after the TGD construction in the Yangtze River Basin. Here, we aimed to analyze the changes in the biodiversity patterns of the fish in the historical and current periods and to explore the effects of geographical and climate characteristics on the biodiversity patterns. The results showed that the fish species diversity in the current period has experienced a significant decrease. An average of 45.3 native species and 19.3 endemic species have been extirpated in the Yangtze River Basin. A total of 113 fish species have been classified as Critically Endangered (22), Endangered (39), Vulnerable (29) and Near Threatened (23). In addition, the alpha and gamma diversity have also decreased significantly. The analysis of the beta diversity showed a significant trend towards taxonomic homogenization. We found significant effects of geographical distance, temperature, precipitation and altitude on the beta diversity. This study will provide important information for the conservation and management of fish biodiversity in the Yangtze River Basin and other areas.

Recent studies have shown that introductions of some organic additives are beneficial for optimizing organic–inorganic hybrid perovskite (OIHP) optoelectronic properties to promote their industrial...

The Raman spectra of two kinds of expansins KT-30 and DA-6 are measured and analyzed in the cases of pure solid-phase and in water solutions. The results show that, KT-30 has much richer and narrower Raman spectral peaks. The first, second, and third strong Raman peaks are respectively located 990.68738 cm−1, 1606.0975 cm−1, and 1327.9379 cm−1. Besides the dense and narrow Raman peaks below 1800 cm−1, there exist three weak peaks within 3050–3410 cm−1. In comparison, fewer spectral peaks can be observed for DA-6. The first and second strong peaks respectively appear at 2883.03760 cm−1 and 2848.4480 cm−1. There exist about 8 peaks below 1500 cm−1. In water solutions, bell-shaped and homogeneous fluorescence background will respectively superpose on the Raman spectra of KT-30 and DA-6 within 100–2500 cm−1 and 400–4000 cm−1. Parts of spectral peaks will be covered accordingly. Moreover, the peak position shifts of KT-30 are very slight. While DA-6 takes the opposite. Its largest shift can even be up to 63.4148 cm−1. The results can supply important fingerprint data for Raman detection of expansins in fruits and vegetables.

The forming/destruction mechanism of conducting filament is essential in understanding the behavior of resistance-memory device. On the basis of filamentary theory, we systematically studied the different electrical performances of both planar and vertical sandwich (metal/organic/metal) memory devices. Bias induced morphological change in gap devices are monitored using scanning electron microscopy system equipped with probes. The in situ images directly demonstrate that with bias increasing, metal clusters emerge inside the channel and further cause sudden switching of device resistance. After clarifying the roles of electrodes and sandwiched organic layer, we conclude a field-dependent filament formation and organics-assistant filament destruction mechanism for resistance memory phenomenon, which should generally exist in all organic electronic devices with metal electrodes.

The paper presents the design and measurement results of a transient waveform recording ASIC based on the Switched Capacitor Array (SCA) architecture. This 0.18 {\mu}m CMOS prototype device contains two channels and each channel employs a SCA of 128 samples deep, a 12-bit Wilkinson ADC and a serial data readout. A series of tests have been conducted and the results indicate that: a full 1 V signal voltage range is available, the input analog bandwidth is approximately 450 MHz and the sampling speed is adjustable from 0.076 to 3.2 Gsps (Gigabit Samples Per Second). For precision waveform timing extraction, careful calibration of timing intervals between samples is conducted to improve the timing resolution of such chips, and the timing precision of this ASIC is proved to be better than 15 ps RMS.

The Yangtze River Basin (Changjiang Basin) hosts one of the most diverse freshwater mussel assemblages on Earth. However, due to human activities this fauna is dramatically imperiled in this region, highlighting the need for urgent conservation measures. To better protect and conserve these taxa, it is crucial to understand the main drivers that control the diversity patterns, as well as the anthropogenic influence on these patterns. Here, we estimated distinct diversity metrics (i.e. species richness and alpha, gamma, and beta diversity) to analyze the spatial freshwater mussel diversity changes across 16 tributaries and lakes from the middle and lower Yangtze River Basin, in two periods: past 1962–2012 and present. For the past, mussel records were compiled from previous studies, for the present, we surveyed 565 sites for freshwater mussel presence and abundance within the 16 selected areas. We also assessed several climatic and geographical parameters to try to identify the main factors that modulate species composition across the study area. We show that from the historical to the present periods, species diversity experienced a significant decrease, registering, per river/lake, an average of 5.4 extirpations of species native to China and 3.9 of the Yangtze River Basin endemics. The gamma diversity of the whole study area and the alpha diversity of each of the studied rivers and lakes have also decreased during this period. The beta diversity values indicated a significant trend towards taxonomic homogenization over the last decades. Poyang and Dongting Lakes should be considered for protection given due to their high diversity and species loss given that nestedness in these lakes represented the main component of beta diversity.

The Luoxiao Mountains play an important role in maintaining and supplementing the fish diversity of the Yangtze River Basin, which is also a biodiversity hotspot in China. However, fish biodiversity has declined rapidly in this area as the result of human activities and the consequent environmental changes. Beta diversity was a key concept for understanding the ecosystem function and biodiversity conservation. Beta diversity patterns are evaluated and important information provided for protection and management of fish biodiversity in the Luoxiao Mountains. The results showed that the spatial turnover component was the main contributor to beta diversity of Hemiramphidae, Amblycipitidae, Catostomidae, Clariidae, Balitoridae and Percichthyidae in the Luoxiao Mountains, which indicated that a number of protected areas would be necessary to conserve fish biodiversity and that these families would need conservation measures. Most protected areas are currently limited to some regions; therefore, in order to protect fish diversity, conservation efforts must target an increase in the number of protected areas which should be spread across each of the regions.

The vertically ordered (small-to-large n) quasi-2D perovskite films serve as common approaches to facilitate directional charge transfer. Here, we report a different strategy of uniformly arranging different-n-value nanoplates (PEA(2)MA(n-1)Pb(n)I(3n+1)) by introducing vacuum poling treatment to enforce nucleation during crystallization. This uniform distribution is verified by delicate mechanical tape-peeling method while monitoring optical absorption, photoluminescence (PL), and energy-dispersive X-ray spectroscopy (EDS). With uniform distribution, efficient carrier transfer within 10 ps is revealed by transient absorption. Moreover, record-high fill factor (FF) of 82.4% with power conversion efficiency (PCE) of 18.04% (Voc = 1.223 V, Jsc = 17.91 mA/cm(2)) was demonstrated. Superior stability is achieved with retaining 96.1% of initial efficiency after 8-month storage and maintaining 97 7% at 80'C for over 180 h. This uniformly arranging different-n-value nanoplates offers a new material engineering strategy to enhance carrier transfer and extraction for developing high-efficiency and stable quasi-2D perovskite solar cells.

Time and charge measurements over a large dynamic range from 1 Photo Electron (P.E.) to 4000 P.E. are required for the Water Cherenkov Detector Array (WCDA), which is one of the key components in the Large High Altitude Air Shower Observatory (LHAASO). To simplify the circuit structure of the readout electronics, a front end ASIC was designed. Based on the charge-to-time conversion method, the output pulse width of the ASIC corresponds to the input signal charge information while time information of the input signal is picked off through a discriminator, and thus the time and charge information can be digitized simultaneously using this ASIC and a following Time-to-Digital Converter (TDC). To address the challenge of mismatch among the channels observed in the previous prototype version, this work presents approaches for analyzing the problem and optimizing the circuits. A new version of the ASIC was designed and fabricated in the GLOBALFOUNDRIES 0.35 um CMOS technology, which integrates 6 channels (corresponding to the readout of the 3 PMTs) in each chip. The test results indicate that the mismatch between the channels is significantly reduced to less than 20% using the proposed approach. The time measurement resolution better than 300 ps is achieved, and the charge measurement resolution is better than 10% at 1 P.E., and 1% at 4000 P.E., which meets the application requirements.

Optoelectronic behavior in materials such as organic/inorganic hybrid perovskites depend on a complex interplay between fast (electronic) and slower (ionic) processes. These processes are thought to be influenced by structural inhomogeneities (e.g. interfaces and grain boundaries) bringing forward the necessity for development of techniques capable of correlating nanostructure and photo-transport behavior. While Kelvin probe force microscopy (KPFM) is ideally suited to map surface potentials on relevant length scales, it lacks sufficient temporal resolution to extract the meaningful system dynamics. Here, we develop a time resolved surface photovoltage (SPV) measurement based on full information capture of the photodetector stream during open loop KPFM operation. G-Mode, or G-KPFM allows quantification of SPV with microsecond temporal and nanoscale spatial resolution. Using this technique, we observe concurrent spatial and fast temporal variations in the SPV generated across a methylammonium lead bromide (MAPbBr3) thin film, a possible indicator relating microstructure with heterogenous photo-transport behavior. We further demonstrate the advantage of adopting big data analytics including unsupervised clustering methods to quickly discern spatial variability in the information rich SPV dataset. Beyond G-KPFM, such clustering methods will be useful for interpretation of the multidimensional datasets arising from the growing number of time resolved KPFM approaches now available.

Two peaks are observed in the capacitance–voltage (C–V) characteristics of electron-transport fullerene (C60 or C70)/Bphen based devices. The experimental results suggest that the mobile carriers generated from unintentional doping and trapped carriers are the origins of these two peaks, just the same as those of hole-transport devices. In addition, the polarity of one C–V peak voltage (the voltage corresponding to the peak capacitance) reverses as the Bphen layer thickness increases. The transient photo-voltage (TPV) signals show a polarity reversal of the internal electric field, confirming the related phenomenon.

The Ganjiang River has abundant fish resources, which plays a significant role in maintaining and replenishing the fish resources in Poyang Lake and the Yangtze River, and contains important habitat for migratory fish. However, fish diversity has rapidly declined in the Ganjiang River, especially migratory fish. In this study, 107 fish species (including 43 Chinese endemic species) were found in the middle and lower reaches of the Ganjiang River. However, only 91 fish species were found in the main channel of the Ganjiang River, which was lower than the 108 fish species historically found there. According to the Chinese Red List, 85 Least Concern, two Critically Endangered, three Vulnerable, one Near Threatened and 16 Data Deficient fish species were found in the Ganjiang River. In addition, the species number, diversity and CPUE in the channel were all greater than in the reservoir. The Bray-Curtis resemblance matrix and non-metric multidimensional scaling (NMDS) showed that the habitats of the Ganjiang River were divided into three areas. The analysis of RDA showed that turbidity, dissolved oxygen and water depth significantly affected fish distributions and assemblage composition. These results indicated that dam construction and other human activities have seriously destroyed the fish habitat and led to the decline in fish diversity. Therefore, the conservation of fish has become urgent in the Ganjiang River, and an integrated management plan should be developed and effectively implemented.

The water Cherenkov detector array (WCDA) is an important part of the large high-altitude air shower observatory (LHAASO), which is in a research and development phase. The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics. To simplify the WCDA’s readout electronics, a prototype of a front-end readout for an application-specific integrated circuit (ASIC) is designed based on the time-over-threshold method to achieve charge-to-time conversion. High-precision time measurement and charge measurement are necessary over a full dynamic range [1–4000 photoelectrons (P.E.)]. To evaluate the performance of this ASIC, a test system is designed that includes the front-end ASIC test module, digitization module, and test software. The first module needs to be customized for different ASIC versions, whereas the digitization module and test software are tested for general-purpose use. In the digitization module, a field programmable gate array-based time-to-digital converter is designed with a bin size of 333 ps, which also integrates an inter-integrated circuit to configure the ASIC test module, and a universal serial bus interface is designed to transfer data to the remote computer. Test results indicate that the time resolution is better than 0.5 ns, and the charge resolution is better than 30% root mean square (RMS) at 1 P.E. and 3% RMS at 4000 P.E., which are beyond the application requirements.

Polarization effects on optoelectronic behaviors in perovskite-based devices are difficult to address due to quick electronic polarization relaxation and ionic polarization from mobile ions. Here we show the effects of polarized excited states on photoluminescence and photocurrent in MAPbBr3 thin-film devices. We found optically polarized transition dipoles, oriented paralleled and perpendicular to device built-in field, give rise to significantly different photoluminescence and photocurrent outcomes. It provides a new understanding that controlling domain geometry can further enhance the light-emitting and photovoltaic performance of perovskite-based applications. The observation proves that the anisotropy of photoexcited transition dipoles is existed in the electronic states of MAPbBr3. Particularly, this indicates that photo-induced electronic polarization can be shown as photoinduced dielectric polarization at the dipolar polarization regime, which impacts device performance. We also observed that increasing photoexcitation intensity leads to a decreases on both field-induced photoluminescence quenching and field-induced photocurrent enhancing, which implies a cooperative interaction between transition dipoles of increased density that favors light emission but infavors charge dissociation. This provides a critical understanding on why organic-inorganic hybrid perovskites can function as efficient photovoltaic and light-emitting materials at low and high excitation intensities, respectively. Our estimation shows that, by manipulating the ratio of dipole orientation, the efficiencies of perovskite-based LEDs and solar cells could be improved by 50% and 18%, respectively. Clearly, the polarization effect presents a new insight on further controlling photovoltaic and light-emitting actions by manipulating the polarization of excited states in perovskite optoelectronics.

This paper reports an amplified spontaneous emission (ASE) initiated by intrinsically passivating grain boundary defects and aligning transition dipoles in polycrystalline perovskite (MAPbBr3) films. The method is developed by using concurrently occurring fast and slow growths to attach small grains on surfaces of large grains toward low-threshold ASE. This materials processing utilizes one-step solution method of mixing two MAPbBr3 precursor (PbBr2-based and Pb(Ac)2 · 3H2O-based) solutions to control two subsequent growths: quickly growing large grains followed by slowly growing small grains, leading to unique emitting centers from large grains and self-doping agents from small grains. With this design, spectral narrowing phenomenon is observed from the large grains with the full width at half maximum decreasing from 21 to 4 nm when the pumping fluence is increased from 2 to 10 µW, generating an efficient ASE. Concurrently, the observed ASE shows a linear polarization reaching 21.1%, indicating that the transition dipoles in large grains are linearly polarized with coherent interaction. Therefore, this processing strategy presents a unique method to intrinsically passivate grain boundary defects and align transition dipoles toward developing ASE by attaching small grains (serving as passivation agent) to the surfaces of large grains (functioning as light-emitting centers).

Lead halide perovskites have demonstrated outstanding achievements in photoelectric applications owing to their unique properties. However, the moisture sensitivity of lead halide perovskite has ra ...

Waveform of the pulse from detectors carry the maximum possible information, and the high demands of fast waveform digitizing led to the development of switched capacitor arrays (SCAs). A prototype of two channels transient waveform digitization ASIC has been designed and fabricated in global foundry 0.18 urn CMOS process. Each channel employs a SCA structure of 128 samples deep, and the high speed sample clock is provided by an on-chip delay-locked loop (DLL). After waveform capture, the analog signal is fed into 128 parallel 12-bit ramp-comparator analog to digital convertors (ADCs), then followed by a serialized readout module with 200 MHz rate. Based on the simulate results, input analog bandwidth is more than 300 MHz and sampling speed can be adjusted from 0.5 to 2 GSa/s, and after amplitude and time calibration, a full 1 V signal voltage range is available, and the Signal-to-Noise Ratio (SNR) reaches 56 dB at 200 MHz input. Data of each channel can be read out in under 10 μs, respectively.

High precision and large dynamic range measurement are required in the readout systems for the Water Cherenkov Detector Array (WCDA) in the Large High Altitude Air Shower Observatory (LHAASO). This paper presents a prototype of a 12-bit 40 MSPS Analog-to-Digital Converter (ADC) Application Specific Integrated Circuit (ASIC) designed for the readout of the LHAASO WCDA. Combining this ADC and the front-end ASIC finished in our previous work, high precision charge measurement can be achieved based on the digital peak detection method. This ADC is implemented based on a power-efficient Successive Approximation Register (SAR) architecture, which incorporates key parts such as a Capacitive Digital-to-Analog Converter (CDAC), dynamic comparator and asynchronous SAR control logic. The simulation results indicate that the Effective Number Of Bits (ENOB) with a sampling rate of 40 MSPS is better than 10 bits in an input frequency range below 20 MHz, while its core power consumption is 6.6 mW per channel. The above results are good enough for the readout requirements of the WCDA.

Organic photovoltaics (OPVs) with three types of double anode buffer layers (DABLs), i.e., 4.5 nm hole-transport material 4,4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl layer, 1 nm electron-transport material Bphen, and 1 nm typical insulator LiF layer, respectively, deposited onto 10 nm MoO3 layer, were fabricated. All these three DABLs can improve the efficiency of CuPc/C60 based planar heterojunction OPV, especially with about 10% enhancement of short-circuit current (ISC). Based on the external quantum efficiency (EQE) and transient photovoltage (TPV) measurements, a mechanism of depressing harmful exciton dissociation at the MoO3/CuPc interface has been proposed. This harmful dissociation results in exciton loss within the CuPc layer, while a proper ultrathin layer inserted at MoO3/CuPc interface can effectively depress the dissociation and thus improve the total photocurrent.

In organic resistive memory device field, alternating current (AC) has seldom been studied systematically. In the present work, square wave voltage pulses are considered to obtain memory switching to the ON state with voltage amplitude lower than the threshold voltage of the device, even with less time. The ON states induced by such AC depend on both frequency and amplitude. A possible mechanism related to filamentary formation was proposed to explain the AC induced effect.

To identify the effect of drift/diffusion current on the fill factor (FF) of organic solar cells, the correlation between FF and drift/diffusion current is studied with thickness/type of donor material, temperature and doping as the experimental parameters. Experimental results show that FF is positively related to the diffusion current. Because of the suppression of carrier diffusion, generated carriers will accumulate at the donor–acceptor interface, resulting in carrier recombination.

Despite quick development of perovskite light-emitting diodes (PeLEDs) during the past few years, the fundamental mechanisms on how ion migration affects device efficiency and stability remain unclear. Here, it is demonstrated that the dynamic redistribution of mobile ions in the emissive layer plays a key role in the performance of PeLEDs and can explain a range of abnormal behaviours commonly observed during the device measurement. The dynamic redistribution of mobile ions changes charge-carrier injection and leads to increased recombination current; at the same time, the ion redistribution also changes charge transport and results in decreased shunt resistance current. As a result, the PeLEDs show hysteresis in external quantum efficiencies (EQEs) and radiance, that is, higher EQEs and radiance during the reverse voltage scan than during the forward scan. In addition, the changes on charge injection and transport induced by the ion redistribution also well explain the rise of the EQE/radiance values under constant driving voltages. The argument is further rationalized by adding extra formamidinium iodide (FAI) into optimized PeLEDs based on FAPbI(3), resulting in more significant hysteresis and shorter operational stability of the PeLEDs. Funding Agencies|ERC Starting GrantEuropean Research Council (ERC) [717026]; Swedish Energy Agency EnergimyndighetenSwedish Energy Agency [48758-1, 44651-1]; Swedish Foundation for International Cooperation in Research and Higher Education [CH2018-7736]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; NSFCNational Natural Science Foundation of China (NSFC) [61774077]; Research and Development Program in Key Areas of Guangdong Province [2019B1515120073, 2019B090921002, 2019B010132004]; China Scholarship CouncilChina Scholarship Council

Orientational manipulation of transition dipole moment (TDM) plays an important role in controlling the polarization of excited states in light emission as well as lasing actions. The present work discovers vertically aligned TDMs in hybrid perovskite films through angle-resolved photoluminescence (PL) measurements, which show enhanced emission through the film edge. With increasing excitation intensity, the edge emission induced by these vertically aligned TDMs becomes dominant and eventually leads to amplified spontaneous emission (ASE) through the edge view. Meanwhile, polarized emission of both PL and electroluminescence (EL) provides further evidence for vertically aligned TDMs. Surprisingly, the degree of polarization (DOP) through the film edge is increased when grain boundary defects are passivated through either stochiometric engineering or self-passivation by mobile ions under working conditions. With increasing DOP, ASE threshold of the perovskite film is reduced owing to enhanced collective behaviors of light-emitting states. This work presents a useful method to manipulate TDMs in organic-inorganic hybrid perovskites. Funding Agencies|ERC Starting GrantEuropean Research Council (ERC) [717026]; Swedish Energy Agency EnergimyndighetenSwedish Energy Agency [48758-1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]