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Aggregation-induced emission (AIE) molecules have great potential to enhance the performance of micronano lasers due to their excellent aggregated luminescence properties, so it is valuable to expand their applications in micronano lasers. In this work, a typical AIE active fluorescent dye motif 9,10-bis(2,2-diphenylvinyl) anthracene (BDPVA) was selected as the gain medium. First, drop-casting was used to fabricate BDPVA single-crystal nanowires, which can be used as Fabry–Perot (FP)-type resonators with a lasing threshold of 49.4 μJ/cm2. Furthermore, we innovatively doped BDPVA molecules as gain mediums into external polymer Whispering-Gallery-Mode (WGM)-type resonators via the emulsion self-assembly method. Fabricated BDPVA-doped polystyrene (PS) microspheres exhibit a much lower lasing threshold of 9.04 μJ/cm2. These results prove that the BDPVA molecules, in addition to realizing the reported AIE single-crystal lasers, can also be used as a guest-doped gain medium in the resonant cavity for obtaining better fluorescence gain. In addition, multimode tunability of two types of lasers has been successfully achieved by tuning the structure of the resonant cavity. This work further expands the application potential of AIE materials and will provide a useful reference for the rational design and fabrication of photonic micronano laser components using AIE materials.

Abstract: In this paper, we synthesized a novel type II cuprous sulfide (Cu2S)–indium sulfide (In2S3) heterostructure nanocrystals with matchstick-like morphology in pure dodecanethiol. The photovoltaic properties of the heterostructure nanocrystals were investigated based on the blends of the nanocrystals and poly(2-methoxy-5-(2′-ethylhexoxy)-p-phenylenevinylene) (MEH-PPV). In comparison with the photovoltaic properties of the blends of Cu2S or In2S3 nanocrystals alone and MEH-PPV, the power conversion efficiency of the hybrid device based on blend of Cu2S–In2S3 and MEH-PPV is enhanced by ~3–5 times. This improvement is consistent with the improved exciton dissociation or separation and better charge transport abilities in type II heterostructure nanocrystals.

Owing to its narrow bandgap and mature preparation process, silicon wafers were widely used to prepare broadband photodetection devices. To address the issue of weak light absorption in the ultraviolet (UV) and infrared regions, surface treatments including sanding by sandpaper and etching by hot alkaline solution were carried out in this article. Numerous defects and microstructures were formed on the surface of the silicon wafer after sanding treatment. Compared with the sanding treatment, hot alkaline solution etching can introduce a few defects and small microstructures, leading to significant enhancement of photocurrent in the entire UV-vis-near-infrared (NIR) region. The responsivity of this silicon-based photoconductive detector has been increased by one order of magnitude when the silicon wafer was etched in NaOH solution at $95~^{\circ }$ C. The main reason for this enhancement is the increase of carrier transport efficiency, resulting from the generation of defects on the surface. The obtained results provide new insight and route for the further development of silicon-based optoelectronic devices.

Distinct doping propagation characteristics between p-doping and n-doping in light-emitting electrochemical cells (LECs) have been highlighted by intensive reports. Typically, there are significant differences in the doping speeds between p-doping and n-doping, with the former exhibiting a sawtooth frontier and the latter displaying a more uniform frontier profile. In addition, experimental observations demonstrate a uniform motion instead of the theoretically suggested accelerated electrochemical doping frontier propagation. Therefore, there is an urgent need to establish a quantitative model that delves into the underlying mechanisms responsible for doping propagation in LECs. In this study, four variables were selected to investigate the detailed mechanism of electrochemical doping propagation: temperature, voltage, and concentrations of salt and solid electrolyte. Fluorescence imaging revealed that the n-doping and p-doping propagations behaved contrarily with increasing temperature and voltage. By numerically fitting the doping propagation frontier, equations were derived to describe the relationship between the speed of electrochemical doping propagation and temperature/voltage. The underlying mechanisms were elucidated, indicating that anions undergo motion through the cooperative effects of electric field drift and concentration diffusion, while cation transport strongly relies on poly(ethylene oxide) (PEO) segmental motions. In other words, the movement of anions within the electrolyte is characterized by a greater degree of freedom, whereas the motion of cations is significantly dependent on the segmental motions of PEO. The resulting equations were well-fitted with experimental data, providing a solid foundation for further theoretical investigations into electrochemical doping in various devices.

Organic phototransistors (OPTs) based on polymers have attracted substantial attention due to their excellent signal amplification, significant noise reduction, and solution process. Recently, the near-infrared (NIR) detection becomes urgent for OPTs with the increased demand for biomedicine, medical diagnostics, and health monitoring. To achieve this goal, a low working voltage of the OPTs is highly desirable. Therefore, the traditional dielectric gate can be replaced by an electrolyte gate to form electrolyte-gated organic phototransistors (EGOPTs), which are not only able to work at voltages below 1.0 V but also are biocompatible. PCDTPT, one of the most popular narrow band gap donor–acceptor copolymer, has been rarely studied in EGOPTs. In this work, an organic NIR-sensitive EGOPT based on PCDTPT is demonstrated with the detectivity of 7.08 × 1011Jones and the photoresponsivity of 3.56 A/W at a low operating voltage. In addition, an existing persistent photoconductivity (PPC) phenomenon was also observed when the device was exposed to air. The PPC characteristic of the EGOPT in air has been used to achieve a phototransistor memory, and the gate bias can directly eliminate the PPC as an erasing operation. This work reveals the underlying mechanism of the electrolyte-gated organic phototransistor memories and broadens the application of the EGOPTs.

The photovoltaic performance of perovskite solar cells (PSCs) is still below the Shockley–Queisser limit due to the impact of defects originated from the surface and the bulk of the perovskite. Hence, it is particularly important to alleviate non-radiative losses in the solar cell by employing an interface modification strategy. We implemented TiO2/CsAC as an electron transport layer to achieve high-performance devices based on diethylammonium bromide (DABr)-doped MAPbI3. The critical role of cesium acetate (CsAC) is designed to improve perovskite crystallization and achieve a high-quality interfacial contact between TiO2and the perovskite layer. TiO2/CsAC promotes the shift of Br ions to form the Br-rich region at the perovskite/HTL interface simultaneously, which can enhance the extraction of holes and block the diffusion of electrons. Attributing to the modification of CsAC to TiO2, the performance of DABr-doped MAPbI3PSC is improved significantly.

The inevitable oxidation of Sn2+and p-type self-doping has plagued the development of two-dimensional (2D) Sn-based perovskite field effect transistors. In this work, we demonstrate the modulation of the properties of phenethylammonium tin iodide ((PEA)2SnI4) perovskite thin films by introducing the aromatic polymer additives of poly(4-vinylphenol) (PVP) and poly(vinyl pyrrolidone) (PVPD) during the crystallization processes, keeping the 2D layered structure of (PEA)2SnI4unchanged. The proposed formation mechanisms of the polymer-assisted (PEA)2SnI4:PVP and (PEA)2SnI4:PVPD films disclose that the interactions between the polymers and (PEA)2SnI4, such as hydrogen bonds, π–π interactions, and coordination bonds, lead to the improvement of the morphology and crystallization as well as the inhibition of Sn2+oxidation of the films. However, the field-effect transistors based on the two polymer-assisted (PEA)2SnI4thin films constructed on the dielectric of poly(vinyl alcohol) (PVA) modified by crosslinking PVP (CL-PVP) exhibit quite a different performance. Compared with the (PEA)2SnI4transistor, without sacrificing the hole mobility, the on–off current ratio of the (PEA)2SnI4:PVP device increases by one order of magnitude, and the subthreshold slope declines slightly due to the reduced leakage current, which results from the reduction of p-type self-doping of the perovskite film and the improved quality of the perovskite/dielectric interface because of the strong π–π interactions between the benzene rings in CL-PVP and (PEA)2SnI4:PVP. In contrast, the (PEA)2SnI4:PVPD transistor exhibits relatively poor overall performance because of the N-vinylpyrrolidone of PVPD. More importantly, employing PVP and PVPD as additives can effectively enhance the chemical stability of (PEA)2SnI4as well as the operational stabilities of the corresponding transistors. Our work provides an effective strategy for selecting chemical additives to improve 2D perovskite properties and suppress the oxidation of Sn-based perovskites, and paves a way toward the future applications of Sn-based perovskite optoelectronic devices with high performance and stability.

Gray leaf spot (GLS) caused by Cercospora zeae-maydisand C. zeinais an extremely devastating leaf disease that limits maize production annually. The use of GLS-resistant maize hybrids is the most cost-effective approach for reducing losses. Resistance to GLS is quantitatively inherited in maize (Zea maysL.) and further sources of resistance remain to be analyzed. Here, we detected qRgls1.06, a major quantitative trait locus for GLS resistance in bin 1.06 that explained approximately 55% of the phenotype variance. Fine mapping over 2 consecutive years localized qRgls1.06to a 2.38-Mb region. Homozygous qRgls1.06WGR/WGRplants in DZ01 background displayed higher GLS resistance and 100-grain weight than DZ01 plants. The GLS responses of several susceptible elite inbred lines were improved by the introduction of qRgls1.06 by marker-assisted backcrossing. Our findings extend the understanding of the genetic basis of resistance to GLS and provide a set of resistant germplasm for genetic improvement of resistance to GLS in maize.

Cerium oxide (CeO2) is one of potential candidates of hydrophobic coatings servicing in harsh environments. In this letter, abraded CeO2 surface was prepared using sandblasting treatment to investigate the wetting mechanism under the condition of impact abrasive wear. The water contact angle (WCA) of the abraded surface increased from 62.8° to 93.7° after aging in ambient air for about 700 h. The hydrophobic self-optimisation mechanism of the abraded CeO2 surface is due to the hierarchical structure formed during impact abrasive wear and the surface adsorption of airborne hydrocarbon, resulting the wetting state changed from “Wenzel state” to “Cassie-Baxter State”.

Hybrid perovskites are known as electrically polarizable semiconductors based on theoretical prediction and experimental information. Here we show the light polarization effects on the photovoltaic actions in perovskite solar cells by optically generating directional and random electronic transition dipoles within asymmetric and symmetric unit structures. In an asymmetric tetragonal unit structure, we observed the stripes with different orientations onto perovskite grains and that the randomly polarized photoexcitation can generate a higher photocurrent (Jsc) by 6.5 ± 0.5% as compared to the linearly polarized photoexcitation at same intensity in the hysteresis-free perovskite solar cells [ITO/PEDOT:PSS/MAPbI3/PC61BM/PEI/Ag]. Clearly, switching the photoexcitation between linear and random polarizations leads to a ΔJsc, which provides an experimental indication that all-directional and one-directional transition dipoles generate higher and lower photocurrents in organic–inorganic hybrid perovskites (MAPbI3) with an asymmetric tetragonal unit structure. This implies that all-directional and one-directional transition dipoles develop stronger and weaker dissociative interactions, consequently giving rise to more and less dissociation toward generating photocurrent. This is confirmed by the experimental observation that the ΔJsc almost disappears when the temperature increases up to 55 °C, where the asymmetric tetragonal structure is changed to a symmetric cubic structure. Furthermore, the ΔJsc is shown to decrease with increasing light intensity. This indicates that the electronic transition dipoles encounter a polarization relaxation caused by mutual interaction. We show that the polarization relaxation time in MAPbI3is comparable to exciton dissociation time (∼ps). This presents the necessary condition to demonstrate light polarization effects of photovoltaic actions in perovskite solar cells.

Quasi-two-dimensional (quasi-2D) perovskites with a multiple quantum well structure can enhance the exciton binding energy and controllable quantum confine effect, which are attractive materials for efficient perovskite light-emitting diodes (PeLEDs). However, the multiphase mixtures contained in these materials would cause nonradiative recombination at the perovskite film surface. Here, a facile solution surface treatment is adopted to improve the multiple quantum well structure of the quasi-2D perovskite emitting layer, which can reduce the influence of defectinduced nonradiative recombination and the electric-field-induced dissociation of excitons for the PeLEDs. The improved multiple quantum well structure is verified by UV absorption spectra and temperature-dependent photoluminescence spectra measurements. The photoluminescence quantum yield of the quasi-2D perovskite film with surface treatment has been approximately increased by 200%. Meanwhile, the electroluminescence device achieves a current efficiency of 45.9 cd/A.

The morphology and composition of nanostructures play important role in their electrochemical properties. Herein, NiCo layered double hydroxide (LDH) nanostructures were prepared by hydrothermal method with NaOH, urea and ammonia as alkaline sources, respectively. The types of alkaline can affect the morphology of the obtained NiCo LDH nanostructures. Compared with the NaOH as alkaline source, NiCo LDHs with urea and ammonia as alkaline sources exhibit obvious nanoflower structure. And the electrode corresponding to ammonia has the highest specific capacity (1498.98 F/g) at a current density of 1 A/g. And the dosage of ammonia was also influenced the composition of the obtained NiCo LDH nanostructures. Moderate ammonia dosage (0.9 mL) would ensure the purity of NiCo LDH, and achieve high specific capacity and high retention rate (82.9 %) at high current density (10 A/g). These obtained results can provide a new idea and sight for the promotion of the related electrochemical devices based on NiCo LDH materials.

Various additives are used to improve the film morphology, crystal quality, and grain size for the sake of enhancing the performance of three-dimensional perovskite solar cells. Although significant enhancement in the performance of devices has been made due to the introduction of additives, an in-depth understanding of the additive-related crystallization kinetics and the growth mechanism is still lacking. Here, the grain growth mechanism of diethylammonium bromide (DABr)-doped MAPbI3is investigated using in situ dynamic microscopy techniques. The results reveal that the alkyl chains of DABr restrain the growth of grains of MAPbI3during spin-coating, and DABr-induced grain mergence during the annealing process, achieving large grains on the micrometer scale. Meanwhile, the crystallization of MAPbI3with DABr is significantly improved and the number of defects is reduced. The solar cell with optimized DABr doping MAPbI3as the active layer presents a higher power conversion efficiency (PCE) of 19.58% with a fill factor of 79.81%.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a promising hole-transporting material for perovskite light-emitting diodes (PeLEDs). However, intrinsic luminance quenching at the PEDOT:PSS/perovskite interface causes deterioration of performance. Here, we develop a facile and effective strategy to passivate the interface defects via the modification of PEDOT:PSS by l-norvaline. As a pre-buried additive, l-norvaline not only reacts with PEDOT:PSS, but also forms the coordination and hydrogen bond with perovskite. We demonstrated that the generation of buried defects at the PEDOT:PSS/perovskite interface originates from the crystallization process of the perovskite film during annealing by in-situ photoluminescence measurements. The surface of l-norvaline-modified PEDOT:PSS can passivate the interfacial defects and inhibit exciton quenching. As a result, the PeLED shows a good device performance with a luminance of 80089 cd m–2at 509 nm and an external quantum efficiency of 13.04%.

Two-dimensional (2D) layered organic–inorganic perovskites have great potential for fabricating field-effect transistors due to their unique structure that enables the horizontal transport of charge carriers in metal-halide octahedra, resembling the transport behavior in semiconducting channels. Their electronic band structures are mainly dominated by the metal-halide octahedra, which eventually determine the optical and electrical characteristics, whereas organic cations have no direct contributions but would impact the electronic structures via distorting the octahedra. So far, high performance has been achieved in 2D Sn perovskites compared to their Pb counterparts because the intrinsic differences of Sn promote transport properties. The champion hole mobility has been obtained in single-ring aromatic phenylethylammonium tin iodide perovskite [(PEA)2SnI4]. However, simple aliphatic monoammonium tin perovskites and their device applications have rarely been reported. Herein, 2D layered n-butylammonium tin iodide perovskite [(BA)2SnI4] thin films have been synthesized by a spin-coating approach. A structural phase transition occurs at about 225 K in the films, accompanied by the changes in the photoluminescence peak and exciton binding energy. Longitudinal optical (LO) phonons are found to govern the scattering of charge carriers and excitons via the Fröhlich interactions in the temperature range 77–300 K. The first-principles calculations predict that the perovskite has excellent transport characteristics comparable to those of molybdenum disulfide (MoS2) and methylammonium lead iodide perovskite (MAPbI3). The (BA)2SnI4thin film field-effect transistors constructed on polymer dielectrics with a maximum hole mobility of 0.03 cm2V–1s–1in ambient conditions have been successfully demonstrated for the first time. Our findings not only offer a deep insight into the physical properties of 2D layered aliphatic monoammonium tin perovskite thin films but also provide important experimental and theoretical guidance for their potential applications in lateral-type flexible optoelectronic devices.

Transition metal thiophosphates (MTPs) are a group of emerging van der Waals materials with widely tunable band gaps. In the MTP family, CdPSe3is demonstrated to possess a wide energy band gap and high carrier mobility, making it a potential candidate in optoelectronic applications. Here, we reported photoelectric response behaviors of both CdPSe3- and CdPSe3/MoS2-based photodetectors (noted as CPS and CM, respectively); these showed prominent photoelectric performances, and the latter proved to be significantly superior to the former. These devices exhibited ultralow dark current at a magnitude order of 10–12A and fine cycle and air stabilities. Compared with CPS, CM demonstrated the highest responsivity (91.12 mA/W) and detectivity (1.74 × 1011Jones) at 5 V under 425 nm light illumination. Besides, CM showed self-powered photoelectric responses at zero bias, which was attributed to the improved separation efficiency of photogenerated carriers by the built-in electric field at the interface of the p–n junction. This work proves a prospect for the CM device in portable, self-powered optoelectronic device applications.

Organic charge-transfer cocrystals are composed of an electron-rich donor molecule and an electron-deficient acceptor molecule, which are bonded together by intermolecular noncovalent interactions such as π–π interactions, hydrogen bonds, halogen bonds, and charge-transfer interactions. These noncovalent interactions influence the cocrystal packing structures and the photoluminescence properties. Herein, four charge transfer cocrystals, pyrene-tetrafluorophthalic anhydride (TFPA), perylene-TFPA, pyrene-tetrachlorophthalic anhydride (TCPA), and perylene-TCPA, were grown by the slow cooling method and the influence of intermolecular noncovalent interactions on the photoluminescence properties were investigated. Cocrystals of pyrene-TFPA and pyrene-TCPA exhibit a yellow rod-like morphology, while both perylene-TFPA and perylene-TCPA exhibit red rod-like shapes. Results indicate that the C–H···X (X = F, Cl, or O) interactions, π–π interactions, and charge-transfer interactions are dramatically affected by the energy difference between the HOMO of the donor and the LUMO of the acceptor. Meanwhile, for the same acceptor molecules, the positions of the photoluminescence peaks of the cocrystals red-shifted with the enhancement of weak noncovalent interactions, which paved the way to tuning the optical properties of charge transfer cocrystals.

The two categories of organic photodetectors (OPDs) can be distinguished as the photodiode mode and the photoconductor mode. The role of the contact between the electrode and active layer in determining the specific type of photodetector is of utmost importance. In this study, the transition of working modes between the photodiode type and the photoconductor type in OPDs is demonstrated. Specifically, OPDs based on the indium tin oxide/Cs2CO3/P3HT: PC61BM/Al (or Au) structure are fabricated. In the corresponding characterization results, distinct working modes are showcased. For the device with the Au electrode, under reverse bias, the photo‐generated charges can efficiently transport to their respective electrodes and subsequently be collected. This behavior aligns with the photodiode type. Conversely, in the device with the Al electrode, the photo‐generated charges accumulate near the interface between the Cs2CO3layer and the active layer. Subsequently, under reverse bias, tunneling charge injection occurs, resulting in the photoconductor type with an external quantum efficiency exceeding 100%. Both the photodiode and photoconductor devices exhibit a high signal‐to‐noise ratio ranging from 104to 105and fast response on the order of microseconds at −0.5 V. In these findings, the possibility of obtaining desirable working‐mode OPDs by manipulating the electrode work function is suggested. In this study, the transition of working modes between the photodiode type and the photoconductor type in organic photodetectors (OPDs) is demonstrated by manipulating the work function of the electrodes. Specifically, OPDs are fabricated based on the indium tin oxide/Cs2CO3/P3HT: PC61BM/Al (or Au) structure. In the corresponding characterization results, distinct working modes exhibited by these devices are showcased.

Following years of pre-service teacher education, novice teachers are often enthusiastic about embarking on the journey in the teaching profession. However, they may not always possess the internal capacity and institutional support to take effective control of their teaching. This paper reports on a case study of the teaching lives of two novice secondary school ESL (English as a second language) teachers in Hong Kong, drawing on qualitative data gathered through individual face-to-face interviews, and supplemented by email exchanges and telephone conversations, over a one-year period. The study investigates how novice English teachers develop their teacher autonomy, and what factors contribute to their development as autonomous English teachers. The paper concludes that novice English teachers in Hong Kong possess the capacity and are also ready for autonomy, and that an invitational, supportive and collaborative school environment plays a decisive role in affording ample opportunities for novices to develop their autonomy in language teaching. The study suggests that novice teachers should become critically aware of the affordances (opportunities, possibilities, invitations, enablements) in their working conditions, and should meanwhile exercise their teacher agency to act on these affordances to pursue their personal-professional development.

Within instructed second language research, there is growing interest in research focusing on primary school vocabulary learning. Research has emphasized classroom-based learning of vocabulary knowledge, with growing focus on the potential for using captioned videos and increased word encounters. The present study investigated the effects of various captioning conditions (i.e. full captioning, keyword captioning, and no captions), the number of word encounters (one and three), and the combinations of these two variables on incidental learning of new words while viewing a video. Six possible conditions were explored. A total of 257 primary school students learning English as a second language (ESL) were divided into six groups and randomly assigned to a condition in which 15 target lexical items were included. A post-test, measuring the recognition of word form/meaning and recall of word meaning, was administered immediately after participants viewed the video. The post-test was not disclosed to the learners in advance. The group viewing the full captioning video scored significantly higher than the keyword captioning group and the no-captioning group. Repeated encounters with the targeted lexical items led to more successful learning. The combination of full captioning and three encounters was most effective for incidental learning of lexical items. This quasi-experimental study contributes to the literature by providing evidence which suggests that captioned videos coordinate two domains (i.e. auditory and visual components) and help ESL learners to obtain greater depth of word form processing, identify meaning by unpacking language chunks, and reinforce the form-meaning link.

Herein, a single‐layer light‐emitting transistor with a good on/off ratio of more than 106is presented based on the iridium complex as a light‐emitter layer. Comprehensive experiments and simulations demonstrate that the thickness of the emitting layer can significantly improve the majority carrier injection in the source electrode. The electrode work function determines the minority carrier injection in the drain electrode, which is crucial for the light emission of the transistor. Furthermore, the increased source injection allows for a higher channel current, thereby increasing drain injection. Most importantly, although the above methods can improve the device channel current and light‐emitting brightness, the electroluminescence efficiency cannot be optimized since the increased minority carriers are much less than the increased majority carriers, resulting in most increased majority carriers cannot be contributed to the charge recombination. To achieve a higher efficient device, the channel current is supposed to be low when a conductive channel is well formed. This goal is achieved by using an ionic liquid gate to replace SiO2gate for fabricating the light‐emitting single‐layer transistor. The efficiency is improved from ≈0.1 to 1.5 cd A−1. This work provides a new strategy for constructing high‐performance single‐layer light‐emitting transistors. This work demonstrates a single‐layer light‐emitting transistor using iridium complex as a light‐emitter. The emitting layer thickness has a significant impact on the majority of carrier injection in the source region. The electrode work function determines the light emission. Furthermore, the single‐layer ionic liquid‐gated light‐emitting transistor achieves a significantly higher electroluminescence efficiency compared with the SiO2‐gated transistor

Encapsulation of luminescent perovskite quantum dots (QDs) into a solid matrix has been approved to be an efficient way to improve their stability. In this work, we reported a green encapsulation method to produce ultrastable CH3NH3PbBr3QDs incorporated into the SiO2matrix. Specifically, fresh-prepared CH3NH3PbBr3QDs were covalently embedded into silica by an aqueous sol–gel method assisted with CH3NH3Br, which not only effectively inhibited the water-driven degradation of QDs through surface coordination, but also strongly stabilized the QDs in solid powder via concentration gradient. As far as we know, this silica encapsulation of perovskite QDs in aqueous environments is reported for the first time. Luminescent properties of perovskite QDs during the course of gelation as well as in resulting composite powder were investigated using steady-state and time-resolved spectroscopies, and a 2 wt % QD-doped sample treated with 11.5 mM of CH3NH3Br was demonstrated to be the optimal phosphor. The green-emissive phosphor had a PLQY of 60.3% and a full width at half maxima of ∼25 nm, exhibiting ultrahigh stability tested by cycle heating (120 °C), continuous heating (80 °C, 60 h), and light irradiation (450 nm light, 350 h). The phosphor was readily blended with polymers and applied as a color-converting layer on blue light-emitting diodes.

A gold-induced NH4Cl-assisted vapor-based route is proposed and developed to achieve vertically aligned submicron Se crystals on lattice-matched (111)-oriented silicon substrates, based on which a high-performance large-area silicon-compatible photodetector is constructed. Thanks to the energy band structure and the strongly asymmetrical depletion region, the fabricated Se/Si device maintains a similar wavelength cutoff to that of selenium devices before the IR region, along with a high-performance broadband photoresponse in the UV-to-visible region. The large-area photodetector maintains a very low leakage current under a −2 V bias, and a high on/off ratio of 103–104is obtained with a high photocurrent of 62 nA at 500 nm. A photoresponse is clearly observed when the bias voltage is removed. The pulse response precisely provides a high response speed (τrise+ τfall≈ 1.975 ms), exceeding the fastest Se-based photodetectors in current reports. The enhanced photoelectric properties and the self-power photoresponse mainly derive from the integrated high-quality Se/n-Si p–n heterojunctions with both lattice match and type II energy band match.

Ternary alloyed Cu2–xSySe1–ynanocrystals (NCs) were synthesized by using a simple and phosphine-free colloidal approach, in which sulfur powder and 1-dodecanethiol (DDT) were used as sulfur sources. In both cases, the crystal phase transformed from cubic berzelianite to monoclinic djurleite structure together with the morphology evolution from quasi-triangular to spherical or discal with an increase of sulfur content. Accordingly, the near-infrared (NIR) localized surface plasmon resonance (LSPR) absorption of the as-obtained sulfur-rich NCs exhibited obvious red-shift of wavelength and widening of absorption width. When the sulfur powder was chosen as sulfur sources, the LSPR wavelength of the as-obtained alloyed Cu2–xSySe1–yNCs could be tuned from 975 to 1230 nm with a decrease of selenium content in the NCs. In contrast, the region of the red-shift could be up to 1250 nm for the alloyed NCs synthesized by incorporation of different DDT dosage into the reaction system. The different sulfur sources and the electron donating effects of the DDT as a ligand played an important role in the LSPR absorption tuning. This deduction could be testified by the post-treating the quasi-triangular Cu2–xSe NCs with DDT under different temperatures and over different reaction time, which exhibited a red-shift of LSPR wavelength up to 450 nm due to coordination of DDT to Cu atoms on the NC surface while incorporating some sulfur anions into the lattice. This study offers a convenient tool for tuning the LSPR absorption of copper chalcogenide NCs and makes them for application in biological and optoelectronic fields.

Self‐powered and flexible photodetectors exhibit great potential in the application of optical communication, deep space exploration, and other related fields. Herein, a self‐powered ultraviolet photodetector based on ZnO nanowires/Te nanowires heterojunction has been prepared by two‐step vacuum filtration method, which also has superior flexibility and fast response speed. The obtained photodetector has a high photocurrent (about 1 μA) at 5 V bias under 365 nm UV light illumination and a fast response speed (3.47/0.13 s). Even if the bending angle reaches 90°, its photocurrent still maintains about 0.5 μA under 5 V bias, showing superior flexibility. Under 0 V bias, the photocurrent of the photodetector is 0.18 nA and the response time is 65/140 ms, displaying its good self‐powered characteristic and fast response speed. These superior properties are caused by the flexibility of ZnO nanowire film and Te nanowire film, and the heterojunction is formed between ZnO and Te. The obtained results provide a solid foundation for the further development of flexible optoelectronic devices based on ZnO nanostructures. A self‐powered ultraviolet photodetector based on ZnO nanowires/Te nanowires heterojunction is prepared. When the bending angle reaches 90°, its photocurrent still maintains about 0.5 μA under 5 V bias, showing superior flexibility. Under 0 V bias, its photocurrent is 0.18 nA and the response time is 65/140 ms, displaying its good self‐powered characteristic and fast response speed.