Efficient Aerial Water Harvesting with Self-Sensing Dynamic Janus Crystals.

Water scarcity is one of the most pressing issues of contemporary societal development that requires innovative technologies where the material not only harvests water but also plays an active role in the process. Here, we demonstrate a highly efficient optical self-sensing approach to humidity capture from the air, where both humidity-harvesting and water-transduction functionalities are imparted on slender organic crystals by partial silanization via layer-by-layer hybridization. We report that due to the integration of the harvesting of aerial moisture and the collection of the condensed water, the ensuing Janus-type crystals capture humidity with the highest-to-date water collection efficiency of 15.

Maneuverability and Processability of Molecular Crystals.

Crystal adaptronics, a burgeoning field at the intersection of materials science and engineering, focuses on harnessing the unique properties of organic molecular crystals to achieve unprecedented levels of maneuverability and processability in various applications. Increasingly, ordered stacks of crystalline materials are being endowed with fascinating mechanical compliance changes in response to external environments. Understanding how these crystals can be manipulated and tailored for specific functions has become paramount in the pursuit of advanced materials with customizable properties.

High-quality quasi-bound state in the continuum enabled single-nanoparticle virus detection.

Bound states in the continuum (BICs) have emerged as a powerful platform for boosting light-matter interactions because they provide an alternative way of realizing optical resonances with ultrahigh quality(Q-) factors, accompanied by extreme field confinement. In this work, we realized an optical biosensor by introducing a quasi-BIC (qBIC) supported by an elaborated all-dielectric dimer grating. Thanks to the excellent field confinement within the air gap of grating enabled by such a high-Q qBIC, the figure of merit (FOM) of a biosensor is up to 18,908.

Simple Isopropanol-Assisted Direct Soft Imprint Lithography for Residue-Free Microstructure Patterning.

A direct soft imprint lithography was proposed to realize the direct fabrication of residue-free, well-shaped functional patterns through a single step. This imprint method requires only a simply prepared isopropanol-treated polydimethylsiloxane (PDMS) stamp without any additional resists. Residue-free Ag patterns were successfully fabricated on different substrates by directly imprinting the Ag ink with the isopropanol-treated PDMS stamp.

Artificial Multi-Stimulus-Responsive E-Skin Based on an Ionic Film with a Counter-Ion Exchange Reagent.

Sensing pressure and temperature are two important functions of human skin that integrate different types of tactile receptors. In this paper, a deformable artificial flexible multi-stimulus-responsive sensor is demonstrated that can distinguish mechanical pressure from temperature by measuring the impedance and the electrical phase at the same frequency without signal interference. The electrical phase, which is used for measuring the temperature, is totally independent of the pressure by controlling the surface micro-shapes and the ion content of the ionic film.

Sensitive Organic Photodetectors With Spectral Response up to 1.3 µm Using a Quinoidal Molecular Semiconductor.

Detecting short-wavelength infrared (SWIR) light has underpinned several emerging technologies. However, the development of highly sensitive organic photodetectors (OPDs) operating in the SWIR region is hindered by their poor external quantum efficiencies (EQEs) and high dark currents. Herein, the development of high-sensitivity SWIR-OPDs with an efficient photoelectric response extending up to 1.

Flexible Organic Chiral Crystals with Thermal and Excitation Modulation of the Emission for Information Transmission, Writing, and Storage.

Organic single crystals quickly emerge as dense yet light and nearly defect-free media for emissive elements. Integration of functionalities and control over the emissive properties is currently being explored for a wide range of these materials to benchmark their performance against organic emissive materials diluted in powders or films. Here, we report mechanically flexible emissive chiral organic crystals capable of an unprecedented combination of fast, reversible, and low-fatigue responses.

Influence of Interaction between Electrolyte with Side-Chain Free Conjugated Polymer on the Performance of Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) offer significant advantages in electrophysiological applications, primarily due to their ability to facilitate ionic-to-electronic conversion and establish a direct interface with the surrounding aqueous environments by using organic mixed ionic-electronic conductors. This study employs a side-chain free n-type conducting polymer, poly(benzodifurandione) (PBFDO), as the channel material in OECTs to scrutinize the interplay between various ion concentrations in electrolytes and the conjugated polymer and to assess their subsequent impact on device performance. Our findings reveal that PBFDO-based OECTs demonstrate superior transfer characteristics, attributed to their high conductivity and remarkable stability in aqueous solutions.

Woven organic crystals.

Woven architectures are prepared by physical entanglement of fibrous components to expand one-dimensional material into two-dimensional sheets with enhanced strength and resilience to wear. Here, we capitalize on the elastic properties of long organic crystals with a high aspect ratio to prepare an array of centimeter-size woven network structures. While being robust to mechanical impact, the woven patches are also elastic due to effective stress dissipation by the elasticity of the individual warp and weft crystals.

Synergistic Halide- and Ligand-Exchanges of All-Inorganic Perovskite Nanocrystals for Near-Unity and Spectrally Stable Red Emission.

All-inorganic perovskite nanocrystals (NCs) of CsPbX (X = Cl, Br, I) are promising for displays due to wide color gamut, narrow emission bandwidth, and high photoluminescence quantum yield (PLQY). However, pure red perovskite NCs prepared by mixing halide ions often result in defects and spectral instabilities. We demonstrate a method to prepare stable pure red emission and high-PLQY-mixed-halide perovskite NCs through simultaneous halide-exchange and ligand-exchange.

Collective photothermal bending of flexible organic crystals modified with MXene-polymer multilayers as optical waveguide arrays.

The performance of any engineering material is naturally limited by its structure, and while each material suffers from one or multiple shortcomings when considered for a particular application, these can be potentially circumvented by hybridization with other materials. By combining organic crystals with MXenes as thermal absorbers and charged polymers as adhesive counter-ionic components, we propose a simple access to flexible hybrid organic crystal materials that have the ability to mechanically respond to infrared light. The ensuing hybrid organic crystals are durable, respond fast, and can be cycled between straight and deformed state repeatedly without fatigue.

SbSe/CdS/ZnO photodetectors based on physical vapor deposition for color imaging applications.

The reported antimony selenide (SbSe) photodetectors (PDs) are still far away from color camera applications mainly due to the high operation temperature required in chemical vapor deposition (CVD) and the lack of high-density PD arrays. In this work, we propose a SbSe/CdS/ZnO PD created by physical vapor deposition (PVD) operated at room temperature. Using PVD, a uniform film can be obtained, so the optimized PD has excellent photoelectric performance with high responsivity (250 mA/W), high detectivity (5.

Bioinspired soft robots based on organic polymer-crystal hybrid materials with response to temperature and humidity.

The capability of stimulated response by mechanical deformation to induce motion or actuation is the foundation of lightweight organic, dynamic materials for designing light and soft robots. Various biomimetic soft robots are constructed to demonstrate the vast versatility of responses and flexibility in shape-shifting. We now report that the integration of organic molecular crystals and polymers brings about synergistic improvement in the performance of both materials as a hybrid materials class, with the polymers adding hygroresponsive and thermally responsive functionalities to the crystals.

Mechanical properties and peculiarities of molecular crystals.

In the last century, molecular crystals functioned predominantly as a means for determining the molecular structures X-ray diffraction, albeit as the century came to a close the response of molecular crystals to electric, magnetic, and light fields revealed that the physical properties of molecular crystals were as rich as the diversity of molecules themselves. In this century, the mechanical properties of molecular crystals have continued to enhance our understanding of the colligative responses of weakly bound molecules to internal frustration and applied forces. Here, the authors review the main themes of research that have developed in recent decades, prefaced by an overview of the particular considerations that distinguish molecular crystals from traditional materials such as metals and ceramics.

High-Performance Solar-Blind UV Phototransistors Based on ZnO/GaO Heterojunction Channels.

High-performance phototransistor-based solar-blind (200-280 nm) ultraviolet (UV) photodetectors (PDs) are constructed with a low-cost thin-film ZnO/GaO heterojunction. The optimized PD shows high spectral selectivity (R254/R365 > 1 × 10) with a photo-to-dark current ratio of ∼10, a responsivity of 113 mA/W, a detectivity of 1.25 × 10 Jones, and a response speed of 41 ms under 254 nm UV light irradiation.

Organic Photodiodes with Thermally Reliable Dark Current and Excellent Detectivity Enabled by Low Donor Concentration.

Reducing the dark current () under reverse bias while maintaining a high external quantum efficiency (EQE) is essential for the practical application of organic photodiodes (OPDs). However, the high of OPDs is generally difficult to reduce because its origin in organic photodiodes is still not well understood and is strongly temperature dependent. To address the issues related to high in typical OPDs, we investigate fullerene-based OPDs with various donor concentrations.

Electrically conductive hybrid organic crystals as flexible optical waveguides.

Hybrid materials capitalize on the properties of individual materials to attain a specific combination of performance assets that is not available with the individual components alone. We describe a straightforward approach to preparation of sandwich-type hybrid dynamic materials that combine metals as electrically conductive components and polymers as bending, momentum-inducing components with flexible organic crystals as mechanically compliant and optically transducive medium. The resulting hybrid materials are conductive to both electricity and light, while they also respond to changes in temperature by deformation.

The Mechanism of the Photostability Enhancement of Thin-Film Transistors Based on Solution-Processed Oxide Semiconductors Doped with Tetravalent Lanthanides.

The applications of thin-film transistors (TFTs) based on oxide semiconductors are limited due to instability under negative bias illumination stress (NBIS). Here, we report TFTs based on solution-processed InO semiconductors doped with Pr or Tb, which can effectively improve the NBIS stability. The differences between the Pr-doped InO (Pr:InO) and Tb-doped InO (Tb:InO) are investigated in detail.

Synergistic Effect of Oxoammonium Salt and Its Counterions for Fabricating Organic Electrochemical Transistors with Low Power Consumption.

The state-of-the-art poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-based organic electrochemical transistors (OECTs) are gaining importance for a variety of biological applications due to their mixed electronic and ionic conductivities featuring ion-to-electron conversion. A low operation voltage without sacrificing device performance is desired to realize long-term monitoring of biological activities. In the present work, oxoammonium salts with two different counterions (TEMPOX, where TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxoammonium; X = Br and TFSI) are employed as secondary dopants to modulate the device performance.

Fluorescence-based thermal sensing with elastic organic crystals.

Operation of temperature sensors over extended temperature ranges, and particularly in extreme conditions, poses challenges with both the mechanical integrity of the sensing material and the operational range of the sensor. With an emissive bendable organic crystalline material, here we propose that organic crystals can be used as mechanically robust and compliant fluorescence-based thermal sensors with wide range of temperature coverage and complete retention of mechanical elasticity. The exemplary material described remains elastically bendable and shows highly linear correlation with the emission wavelength and intensity between 77 K to 277 K, while it also transduces its own fluorescence in active waveguiding mode.

Doping Compensation Enables High-Detectivity Infrared Organic Photodiodes for Image Sensing.

Infrared organic photodiodes have gained increasing attention due to their great application potentials in night vision, optical communication, and all-weather imaging. However, the commonly occurring high dark current and low detectivity impede infrared photodetectors from portable applications at room temperature. Herein, an efficient and generic doping compensation strategy is developed to improve the detectivity of infrared organic photodiodes.

Remote and precise control over morphology and motion of organic crystals by using magnetic field.

Elastic organic crystals are the materials foundation of future lightweight flexible electronic, optical and sensing devices, yet precise control over their deformation has not been accomplished. Here, we report a general non-destructive approach to remote bending of organic crystals. Flexible organic crystals are coupled to magnetic nanoparticles to prepare hybrid actuating elements whose shape can be arbitrarily and precisely controlled simply by using magnetic field.