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Quantum dots (QDs) often exhibit unique behaviors because the reduction in lateral size leads to stronger quantum confinement effects and a higher surface-to-volume ratio in comparison with larger two-dimensional nanosheets. However, the preparation of homogeneous QDs remains a longstanding challenge. This work reports the preparation of high-yield and ultrasmall tin disulfide (SnS2) QDs by combining top–down and bottom–up approaches. The as-prepared SnS2QDs have a uniform lateral size of 3.17 ± 0.62 nm and a thicknesses 2.39 ± 0.88 nm. A series of self-powered photoelectrochemical-type photodetectors (PDs) utilizing the SnS2QDs as photoelectrodes are also constructed. Taking advantage of the tunable bandgaps and high carrier mobility of the SnS2, our PDs achieve a high photocurrent density of 16.38 μA cm−2and a photoresponsivity of 0.86 mA W−1, and good long-term cycling stability. More importantly, the device can display obvious photoresponse, even at zero bias voltage (max), and greater weak-light sensitivity than previously reported SnS2-based PDs. Density functional theory calculation and optical absorption were employed to reveal the working mechanism of the SnS2QDs-based PDs. This study highlights the prospective applications of ultrasmall SnS2QDs and provides a new route towards future design of QDs-based optoelectronic devices.

In this work, MXene films incorporating cellulose nanofibers (CNFs) with a spider-web-like structure were fabricated using a facile vacuum-assisted filtration method. The CNFs significantly improved the flexibility and stability of the MXene membranes. The resulting composites functioned well as electrodes and friction layers in triboelectric nanogenerators (TENGs) when paired with either polytetrafluoroethylene (PTFE) as an electropositive material or nylon as an electronegative material. A membrane containing 20 wt % CNFs in conjunction with PTFE was extremely effective during the prolonged operation of a TENGs, generating an output voltage in excess of 1120 V at a frequency of 3.5 Hz. The surface charge density of this device was as high as 100 μC m–2. When paired with nylon, the MXene/CNF film produced a surface charge density of over 60 μC m–2. The microstructures on the rough surface of these membranes, together with the presence of −F and other polar terminations on the MXene, are responsible for the high performance of the nanocomposite. This work demonstrates that MXenes are not necessarily equivalent to PTFE within the triboelectric series and suggests that the MXene-based friction layer could greatly enhance the performance of TENGs.

Precise exfoliation and modification of nano-Tellurium was realized by adopting a room-temperature ionic liquid as the electrolyte.Nano-Tellurium with high-entropy morphology can offer greater solar absorption and more kinds of surface chemical groups, giving rise to superior photothermal properties.Nano-Tellurium-poly(vinyl alcohol)-based photothermal foam hydrogels, with high compressibility, excellent water transport rate and low evaporation enthalpy of water, combined with a new heat-supply model, achieve an evaporation rate of 4.11 kg m−2h−1with energy efficiencies up to 128% under 1 sun irradiation, which are the highest values for semiconductor-based nanocomposites reported so far.

Humidity sensors have broad applications in health monitoring, environmental protection and human-machine interface, and robotics. Here, we developed a humidity sensor using alkali oxidation method to grow in situ TiO2nanowires on two-dimensional Ti3C2MXene. With an order of magnitude larger surface area compared to pure Ti3C2or TiO2materials, the urchin-like Ti3C2/TiO2composite demonstrates a record high sensitivity in a low relative humidity (RH) environment (∼280 pF/% RH from 7% RH to 33% RH). Complex impedance spectroscopy and Schottky junction theory were employed to understand the underlying sensing mechanisms of the Ti3C2/TiO2composite under various humidity conditions. We demonstrate the application of humidity sensors made with the Ti3C2/TiO2composite for noncontact detection of the presence of various liquids as well as human fingers.

Owing to the attractive energy band properties, a black phosphorus (BP)-analogue semiconductor, germanium selenide (GeSe), shows a promising potential applied for optoelectronic devices. Herein, ultrathin GeSe nanosheets were systematically prepared via a facile liquid-phase exfoliation approach, with controllable nanoscale thickness. Different from BP, ultrathin GeSe nanosheets exhibit good stability under both liquid and ambient conditions. Besides, its ultrafast carrier dynamics was probed by transient absorption spectroscopy. We showed that the GeSe nanosheet-based photodetector exhibits excellent photoresponse behaviors ranging from ultraviolet (UV) to the visible regime, with high responsivity and low dark current. Furthermore, the detective ability of such a device can be effectively modulated by varying the applied bias potential, light intensity, and concentration of the electrolyte. Generally, our present contribution could not only supply fundamental knowledge of a GeSe nanosheet-based photoelectrochemical (PEC)-type device, but also offer guidance to extend other possible semiconductor materials in the application of the PEC-type photodetector.

•Two-dimensional (2D) pnictogens have aroused significant attention in recent years.•From a chemistry viewpoint, covalent functionalization of 2D pnictogens affords modifications of structures and physical properties with controllability, adjustability and diversity relative to noncovalent functionalization, which provides much more opportunities to improve both chemical stability and semi-conducting properties of 2D pnictogens.

Two-dimensional (2D) MXenes have recently been shown to be promising for applications in anticancer photothermal therapy (PTT), owing to their outstanding photothermal performance. However, as with the other inorganic 2D nanomaterials, the MXene-based nanoplatforms lack the appropriate biocompatibility and stability in physiological conditions, targeting capability, and controlled release of drug, for cancer therapy. Fabricating a smart MXene-based nanoplatform for the treatment of cancer therefore remains a challenge. In this work, composite hydrogels based on cellulose and Ti3C2MXene, were synthesized for the first time. We have shown that the cellulose/MXene composite hydrogels possess rapid response near-infrared-stimulated characteristics, which present as a continuous dynamic process in water. As a result, when loaded with the anticancer drug doxorubicin hydrochloride (DOX), the cellulose/MXene hydrogels are capable of significantly accelerating the DOX release. This behavior is attributed to the expansion of the pores within the three-dimensional cellulose-based networks, triggered by illumination with an 808 nm light. Capitalizing on their excellent photothermal performance and controlled, sustained release of DOX, the cellulose/MXene hydrogels are utilized as a multifunctional nanoplatform for tumor treatment by intratumoral injection. The results showed that the combination of PTT and prolonged adjuvant chemotherapy delivered using this nanoplatform was highly efficient for instant tumor destruction and for suppressing tumor relapse, demonstrating the potential of the nanoplatform for application in cancer therapy. Our work not only opens the door for the fabrication of smart MXene-based nanocomposites, along with their promising application against cancer, but also paves the way for the development of other inorganic 2D composites for applications in biomedicine.

Nanostructured polymeric composites, based on a homopolymer poly(vinylidene fluoride) (PVDF) and a small molecule, 1-vinyl-3-butylimidazolium chloride [VBIM][Cl], an unsaturated room-temperature ionic liquid (IL) have been fabricated. Our strategy forms organic conductive nanodomains with diameters of 20–30 nm dispersed homogeneously in the PVDF matrix. It is demonstrated that these conductive nanodomains are induced from microphase separation of the IL grafted PVDF (PVDF-g-IL) segments from the neat PVDF, which were produced by using electron-beam irradiation, leading IL molecules to graft onto the amorphous PVDF chains. It is also found that such microphase separation of PVDF-g-IL segments from PVDF matrix occurs only when the grafted IL content exceeds 3 wt %. Furthermore, the formed nanodomains enhance the crystallization rate of the matrix PVDF. The obtained nanostructured PVDF composites show dominant nonpolar α-phase of PVDF crystals and increased crystal long period (L) compared with neat PVDF. Additionally, the resulting nanostructured PVDF composites exhibit enhanced electrical properties, better Young’s modulus and ductility, and improved dielectric performance compared with neat PVDF, making the composites promising for potential use in superthin dielectric capacitors. The intriguing synthesis route will open up new opportunities for fabricating nanostructured polymer composites.

Tactile sensors can enable a robotic manipulator to identify the object in contact. However, due to the dynamics and diversity of target objects, as well as the complexity of real environment, accurate recognition of objects by existing tactile sensors has been very challenging. This paper proposes a hybrid tactile sensor that integrates a triboelectric active sensing unit with an electromagnetic inductance transducer. The triboelectric signal relates strongly to the specific charge condition of the surface material of a target object, while the inductive signal manifests the electromagnetic characteristics at a certain depth inside the object. With the help of machine learning, the triboelectric signals and inductive signals can be used for object identification. We demonstrate a robotic gripper with random operation settings can recognize eight different fruits with an accuracy as high as 98.75%. Furthermore, the hybrid sensor can recognize objects packaged in different ways. The recognition accuracy of four different fruits in three different packages can reach 95.93%. This study demonstrates the potential of hybrid tactile sensor to improve the artificial intelligence of robots, in particular their ability to distinguish objects in complex settings and sorting them effectively.

We propose a novel vortex-induced vibration (VIV) based triboelectric nanogenerator (TENG) that makes it possible for efficient energy harvesting from wind at low speed. A theoretical model for VIV-TENG is constructed to investigate the vibration response and output voltage varying with wind speed, which is compared with and validated by experiments. Results show that there is a lock-in region where the vibration amplitude and output voltage are large. When the wind speed is 2.78 m/s, the average power is achieved to be 392.72 μW and the average power density is 96.79 mW/m2, which are much higher than those reported in previous studies. In order to broaden the lock-in region, we further design a new model of tandem vortex-induced vibration triboelectric nanogenerators. The resonance wind speed region is remarkably widened due to interactions between two cylinders subjected to VIV. The demonstration of continuously powering wireless sensors is performed to show the practicability of the designed VIV-TENG. Overall, the present study enables applications of TENG for realizing self-powered wireless sensing under low wind speed environments.

Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.

Belonging to the chalcogen group, the elements selenium (Se) and tellurium (Te) are located in Group VI‐A of the periodic table. Zero‐valent nanodimensioned Se (nano‐Se) and Te (nano‐Te) have displayed important biomedical applications in recent years. The past two decades have witnessed an explosion in novel cancer treatment strategies using nano‐Se and nano‐Te as aggressive weapons against tumors. Indeed, they are both inorganic nanomedicines that suppress tumor cell proliferation, diffusion, and metastasis. Abundant synthesis strategies for rational and precise surface decoration of nano‐Se and nano‐Te make them significant players in resisting cancers by means of powerful multi‐modal treatment methods. This review focuses on the design and engineering of nano‐Se‐ and nano‐Te‐based nanodelivery systems and their precise uses in cancer treatment. The corresponding anticancer molecular mechanisms of nano‐Se and nano‐Te are discussed in detail. Given their different photo‐induced behaviors, the presence or absence of near infrared illumination is used as a defining characteristic when describing the anticancer applications of nano‐Se and nano‐Te. Finally, the challenges and future prospects of nano‐Se and nano‐Te are summarized and highlighted. This review focuses on the design and engineering of nano‐Se‐ and nano‐Te‐based nanodelivery systems and their precise uses in cancer treatment. The corresponding anticancer molecular mechanisms of nano‐Se and nano‐Te with or without near infrared illumination are discussed in detail. Finally, the challenges and future prospects of nano‐Se and nano‐Te are summarized and highlighted.

Black phosphorus (BP) has recently emerged as an intriguing photothermal agent in photothermal therapy (PTT) against cancer by virtue of its high photothermal efficiency, biocompatibility, and biodegradability. However, naked BP is intrinsically characterized by easy oxidation (or natural degradation) and sedimentation inside the tumor microenvironment, leading to a short‐term therapeutic and inhomogeneous photothermal effect. Development of BP‐based nanocomposites for PTT against cancer therefore remains challenging. The present work demonstrates that green and injectable composite hydrogels based on cellulose and BP nanosheets (BPNSs) are of great efficiency for PTT against cancer. The resultant cellulose/BPNS‐based hydrogel possesses 3D networks with irregular micrometer‐sized pores and thin, strong cellulose‐formed walls and exhibits an excellent photothermal response, enhanced stability, and good flexibility. Importantly, this hydrogel nanoplatform is totally harmless and biocompatible both in vivo and in vitro. This work may facilitate the development of BP–polymer‐based photothermal agents in the form of hydrogels for biomedical‐related clinic applications. 3D composite hydrogels based on 2D black phosphorus (BP) nanosheets and celluloseare developed in this work. Their morphology, physical properties, and biocompatibility/toxicity are investigated. Based on these characterizations, the 3D cellulose/BP composite hydrogel‐based nanoplatforms are realized for photothermal therapy against cancer, and their performance is evaluated.

In article number 1701510, Liping Liu, Han Zhang, and co‐workers demonstrate that green and injectable composite hydrogels based on cellulose and Black Phosphorus (BP) nanosheets (BPNSs) are of great efficiency for photothermal therapy (PTT) against cancer. The cellulose/BPNS‐based hydrogel possesses 3D networks with irregular micrometer‐sized pores and thin, strong cellulose‐formed walls and exhibits an excellent photothermal response, enhanced stability, and good flexibility.