bluuebunny/crossref_metadata_2025 huggingface dataset:
Van der Waals Heteroepitaxy of GaSe and InSe, Quantum Wells, and Superlattices
Authors: Claro Marcel S. , Martínez‐Pastor Juan P. , Molina‐Sánchez Alejandro , Hajraoui Khalil El , Grzonka Justyna , Adl Hamid Pashaei , Fuertes Marrón David , Ferreira Paulo J. , Bondarchuk Oleksandr , Sadewasser Sascha
Published: January 2023

Bandgap engineering and quantum confinement in semiconductor heterostructures provide the means to fine‐tune material response to electromagnetic fields and light in a wide range of the spectrum. Nonetheless, forming semiconductor heterostructures on lattice‐mismatched substrates is a challenge for several decades, leading to restrictions for device integration and the lack of efficient devices in important wavelength bands. Here, it is shown that the van der Waals epitaxy of 2D GaSe and InSe heterostructures occur on substrates with substantially different lattice parameters, namely silicon and sapphire. The GaSe/InSe heteroepitaxy is applied in the growth of quantum wells and superlattices presenting photoluminescence and absorption related to interband transitions.
3D Printing of Arbitrary Perovskite Nanowire Heterostructures
Authors: Chen Mojun , Zhou Zhiwen , Hu Shiqi , Huang Nan , Lee Heekwon , Liu Yu , Yang Jihyuk , Huan Xiao , Xu Zhaoyi , Cao Sixi , Cheng Xiang , Wang Ting , Yu Siu Fung , Chan Barbara Pui , Tang Jinyao , Feng Shien‐Ping , Kim Ji Tae
Published: January 2023

Deterministic integration of arbitrary semiconductor heterostructures opens a new class of modern electronics and optoelectronics. However, the realization of such heterostructures continues to suffer from impracticality, requiring energy‐ and labor‐intensive, time‐consuming fabrication processes. Here a 3D printing approach to fabricate freestanding metal halide perovskite nanowire heterostructures with a high degree of control over shape and composition is demonstrated. These features arise from freeform guiding of evaporation‐driven perovskite crystallization by a femtoliter precursor meniscus formed on a printing nozzle. By using a double‐barreled nanopipette as a printing nozzle, “all‐at‐once” heterostructure fabrication is achieved within seconds. The 3D‐printed perovskite nanowire heterojunctions with multiple emission colors provide exciting optical functionalities such as programmable color mixing and encryption at the single nanopixel level. This “lithography‐free” additive approach opens up the possibility to freely design and realize heterostructure‐based devices without the constraints of traditional manufacturing processes.
A Novel InSe‐FET Biosensor based on Carrier‐Scattering Regulation Derived from the DNA Probe Assembly‐Determined Electrostatic Potential Distribution
Authors: Ji Hao , Wang Zhenhua , Wang Shun , Wang Chao , Chu Yujin , Liu Hong , Zhang Yu , Han Lin
Published: January 2023

Low‐dimensional material field‐effect transistor (FET)‐based biosensors have the advantages of high sensitivity, high detection speed, small size, low cost, and excellent compatibility with integrated circuits. The sensing mechanism is extremely important in the design and fabrication of high‐performance FET biosensors in practical applications. Herein, an InSe‐FET biosensor is designed and its dominant sensing mechanism during detection and (mi)RNA detection performance are investigated. Finite element analysis reveals the electrostatic potential distribution in the InSe channel with DNA probe assembly showing that Coulomb scattering is the dominant sensing mechanism for carrier scattering‐sensitive InSe. The simulation and experimental results indicate that carriers in InSe are extremely sensitive to the scattering of surface impurities because of their small electron mass. The firstly reported back‐gate bias working mode of an InSe‐FET biosensor has a linear relationship with an extra‐large detectable range of 1 fM–10 nM, high specificity for identifying 1‐nucleotide polymorphisms, and excellent repeatability and reusability. The detection of biomarker miRNAs in clinical serum samples and specific RNA in SARS‐CoV‐2 pseudovirus samples indicate promising applications of InSe‐FET biosensors in critical disease screening and the fast diagnoses of infectious diseases. This study can be useful for the design and fabrication of high‐performance FET biosensors.
Highly Nonstoichiometric YAG Ceramics with Modified Luminescence Properties
Authors: Cao Weiwei , Becerro Ana Isabel , Castaing Victor , Fang Xue , Florian Pierre , Fayon Franck , Zanghi Didier , Veron Emmanuel , Zandonà Alessio , Genevois Cécile , Pitcher Michael J. , Allix Mathieu
Published: January 2023

Y3Al5O12 (YAG) is a widely used phosphor host. Its optical properties are controlled by chemical substitution at its YO8 or AlO6/AlO4 sublattices, with emission wavelengths defined by rare‐earth and transition‐metal dopants that have been explored extensively. Nonstoichiometric compositions Y3+xAl5‐xO12 (x ≠ 0) may offer a route to new emission wavelengths by distributing dopants over two or more sublattices simultaneously, producing new local coordination environments for the activator ions. However, YAG typically behaves as a line phase, and such compositions are therefore challenging to synthesize. Here, a series of highly nonstoichiometric Y3+xAl5‐xO12 with 0 ≤ x ≤ 0.40 is reported, corresponding to ≤20% of the AlO6 sublattice substituted by Y3+, synthesized by advanced melt‐quenching techniques. This impacts the up‐conversion luminescence of Yb3+/Er3+‐doped systems, whose yellow‐green emission differs from the red‐orange emission of their stoichiometric counterparts. In contrast, the YAG:Ce3+ system has a different structural response to nonstoichiometry and its down‐conversion emission is only weakly affected. Analogous highly nonstoichiometric systems should be obtainable for a range of garnet materials, demonstrated here by the synthesis of Gd3.2Al4.8O12 and Gd3.2Ga4.8O12. This opens pathways to property tuning by control of host stoichiometry, and the prospect of improved performance or new applications for garnet‐type materials.
Solubility‐Boosted Molecular Sieving‐Based Separation for Purification of Acetylene in Core–Shell IL@MOF Composites
Authors: Yang Jincai , Tong Minman , Han Guopeng , Chang Miao , Yan Tongan , Ying Yunpan , Yang Qingyuan , Liu Dahuan
Published: January 2023

Considering the small amount of CO2 as a contaminant in industrial gas mixtures, developing CO2‐selective adsorbents exhibit advantages in directly obtaining pure C2H2 in one‐step to reduce the energy consumption. However, it is still a great challenge due to the essential molecular feature of C2H2, including the triple bond and high polarizability. Herein, a simple but effective CO2‐facilitated transport strategy is presented to realize the overwhelming adsorption of CO2 over C2H2 by constructing core–shell composite structures using ionic liquid (IL) and metal‐organic framework (MOF). With the aid of excellent solubility of CO2 in IL and almost total exclusion of C2H2, the obtained materials boost molecular sieving‐based separation of CO2/C2H2. Density functional theory calculations combining molecular dynamic simulations revealed the solution‐diffusion mechanism for CO2, which is rarely reported in solid adsorbents. Ideal adsorbed solution theory selectivity for CO2/C2H2 with 1/1 and 1/3 volume ratios can reach over 104 and 4000 at 100 kPa with a high CO2 uptake of 40.3 cm3 g−1, superior to those of the reported materials so far. More importantly, this solution‐based separation strategy can avoid the difficulty for precise control of the regulation of adsorbent structure, which may be beneficial to practical production.
Intact Metal/Metal Halide van der Waals Junction Enables Reliable Memristive Switching with High Endurance
Authors: Lee Joo‐Hong , Yang June‐Mo , Kim So‐Yeon , Baek Sungpyo , Lee Sungjoo , Lee Sung‐Joon , Park Nam‐Gyu , Lee Jin‐Wook
Published: January 2023

Organic–inorganic or inorganic metal halide materials have emerged as a promising candidate for a resistive switching material owing to their ability to achieve low operating voltage, high on–off ratio, and multi‐level switching. However, the high switching variation, limited endurance, and poor reproducibility of the device hinder practical use of the memristors. In this study, a universal approach to address the issues using a van der Waals metal contact (vdWC) is reported. By transferring the pre‐deposited metal contact onto the active layers, an intact junction between the metal halide and contact layer is formed without unintended damage to the active layer caused by a conventional physical deposition process of the metal contacts. Compared with the thermally evaporated metal contact (EVC), the vdWC does not degrade the optoelectronic quality of the underlying layer to enable memristors with reduced switching variation, significantly enhanced endurance, and reproducibility relative to those based on the EVC. By adopting various metal halide active layers, versatile utility of the vdWC is demonstrated. Thus, this vdWC approach can be a useful platform technology for the development of high‐performance and reliable memristors for future computing.
A Tunable Polarization Field for Enhanced Performance of Flexible BaTiO3@TiO2 Nanofiber Photodetector by Suppressing Dark Current to pA Level
Authors: Su Li , Yan Tingting , Liu Xinya , Cao Fa , Fang Xiaosheng
Published: January 2023

The flexible titanium dioxide (TiO2) nanofibers (NFs) film are promising candidates for high‐performance wearable optoelectronic devices. However, the TiO2 ultraviolet photodetectors (UV PDs) generally suffer from low photosensitivity, which limits the practical applications. Herein, a TiO2 (TO) NFs film flexible photodetector integrated by ferroelectric BaTiO3 (BTO) NFs is developed via electrospinning technology with double sprinklers and in situ heat treatment. Compared with TO NFs PD with poor on/off ratio ≈44, the BTO@TO NFs PD‐2 exhibits an excellent on/off ratio of ≈1.5  × 104 due to the dramatically restrained dark current. The ultralow dark current (pA level) is attributed to the depletion of photogenerated carriers by the space high‐resistance state induced by the downward self‐polarization field in ferroelectric BaTiO3 NFs. The ferroelectric domain with larger downward orientation in polarized BTO@TO NFs exhibits stronger self‐polarization field to modify the directional transport of photogenerated carriers and enhances the band bending level, which improves the photocurrent of device. The special structure woven by ferroelectric nanofiber with self‐polarization will provide a promising approach for improving the performance of flexible photodetectors.
Mitigating Detrimental Effect of Self‐Doping Near the Anode in Highly Efficient Organic Solar Cells
Authors: Kim Yong Ryun , Sandberg Oskar J. , Zeiske Stefan , Burwell Gregory , Riley Drew B. , Meredith Paul , Armin Ardalan
Published: January 2023

Poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been one of the most established hole transport layers (HTL) in organic solar cells (OSCs) for several decades. However, the presence of PSS− ions is known to deteriorate device performance via a number of mechanisms including diffusion to the HTL‐active layer interface and unwanted local chemical reactions. In this study, it is shown that PSS− ions can also result in local p‐doping in the high efficiency donor:non‐fullerene acceptor blends – resulting in photocurrent loss. To address these issues, a facile and effective approach is reported to improve the OSC performance through a two‐component hole transport layer (HTL) consisting of a self‐assembled monolayer of 2PACz ([2‐(9H‐Carbazol‐9‐yl)ethyl]phosphonic acid) and PEDOT:PSS. The power conversion efficiency (PCE) of 17.1% using devices with PEDOT:PSS HTL improved to 17.7% when the PEDOT:PSS/2PACz two‐component HTL is used. The improved performance is attributed to the overlaid 2PACz layer preventing the formation of an intermixed p‐doped PSS− ion rich region (≈5–10 nm) at the bulk heterojunction‐HTL contact interface, resulting in decreased recombination losses and improved stability. Moreover, the 2PACz monolayer is also found to reduce electrical shunts that ultimately yield improved performance in large area devices with PCE enhanced from 12.3% to 13.3% in 1 cm2 cells.
Highly Damping and Self‐Healable Ionic Elastomer from Dynamic Phase Separation of Sticky Fluorinated Polymers
Authors: Xiang Huai , Li Xiaoxia , Wu Baohu , Sun Shengtong , Wu Peiyi
Published: January 2023

Shock‐induced low‐frequency vibration damage is extremely harmful to bionic soft robots and machines that may incur the malfunction of fragile electronic elements. However, current skin‐like self‐healable ionic elastomers as the artificial sensing and protecting layer still lack the ability to dampen vibrations, due to their almost opposite design for molecular frictions to material's elasticity. Inspired by the two‐phase structure of adipose tissue (the natural damping skin layer), here, a highly damping ionic elastomer with energy‐dissipating nanophases embedded in an elastic matrix is introduced, which is formed by polymerization‐induced dynamic phase separation of sticky fluorinated copolymers in the presence of lithium salts. Such a supramolecular design decouples the elastic and damping functions into two distinct phases, and thus reconciles a few intriguing properties including ionic conductivity, high stretchability, softness, strain‐stiffening, elastic recovery, room‐temperature self‐healability, recyclability, and most importantly, record‐high damping capacity at the human motion frequency range (loss factor tan δ > 1 at 0.1–50 Hz). This study opens the door for the artificial syntheses of high‐performance damping ionic skins with robust sensing and protective applications in soft electronics and robotics.
Room Temperature Electronic Functionalization of Thermally Sensitive Substrates by Inkjet Printing of a Reactive Silver‐Based MOD Ink
Authors: Zhou Ye , Xu Zongpu , Bai Hao , Knapp Caroline E.
Published: January 2023

The developments in inkjet printing technology and the printed electronics industry in the past two decades have provided cost‐effective, environment‐friendly, and reliable alternates to traditional methods of fabricating electrical devices. However, most commercial metallic inks require high sintering temperatures to form desired functional patterns, which limits the applications of printed electronics in scenarios that require electrical devices on thermally sensitive substrates, like biomaterials or bio‐synthetic composite materials. This study provides the synthetic route of a novel silver‐based metal organic decomposition (MOD) ink which is used to form highly conductive silver films on the thermally sensitive skin‐inspired silk/epoxy composite substrates by directly inkjet printing with accurate pattern control, whilst self‐decomposing and sintering at room temperature. The fabricated silver patterns on the thermally sensitive silk/epoxy composite substrate are highly conductive with conductivity of 4.65 × 104 S m−1. These silver patterns also show impressive malleability as bulk silver films, which can be further developed into motion sensors for wearable devices or medical applications. Our strategy provides a general platform for electronic functionalization without temperature constraints. The particle‐free, reactive silver‐precursor, and lower sintering temperature of the ink also widen the choices of substrates, as exemplified herein with outstanding printing quality and high electrical conductivity (1.20 × 106 S m−1) also achieve on paper.
Porous Low‐Loss Silica–PMMA Dielectric Nanocomposite for High‐Frequency Bullet Lens Applications
Authors: Palvölgyi Petra S. , Kokkonen Mikko , Sliz Rafal , Jantunen Heli , Kordas Krisztian , Myllymäki Sami
Published: January 2023

Several devices of the future generation wireless telecommunication technologies that use bands in THz frequencies for data transmission need low‐loss and low‐permittivity materials to enable ideal conditions for the propagation of electromagnetic waves. Herein, a lightweight dielectric bullet‐shaped lens operating in the frequency range of 110–170 GHz is demonstrated to collimate electromagnetic waves, thus increasing the intensity of the electric field. The material of the lens is based on a composite of silica nanoshells and poly(methylmethacrylate) made by the impregnation of the nanoshells with the polymer followed by hot pressing in a mold. As the polymer acts only as an adhesive between the hollow nanospheres without filling the inner cavity of the shells and their interparticle spaces, the composite is highly porous (67%) and has low dielectric permittivity and loss tangent (1.5 and 4 × 10−3, respectively, below 200 GHz). The size of the collimated beam and the increase of the corresponding field strength are measured to vary from 2.2 to 1.2 mm and from 17.2 to 8.98 dB depending on the frequency of the waves (110–170 GHz).
Ultraefficient on‐Chip Supercontinuum Generation from Sign‐Alternating‐Dispersion Waveguides
Authors: Zia Haider , Ye Kaixuan , Klaver Yvan , Marpaung David , Boller Klaus-Jochen
Published: January 2023

Fully integrated supercontinuum sources on‐chip are critical to enabling applications such as portable and mechanically stable medical imaging devices, chemical sensing, and light detection and ranging. However, the low efficiency of current supercontinuum generation schemes prevents full on‐chip integration. Herein, a scheme where the input energy requirements for integrated supercontinuum generation are drastically lowered by orders of magnitude is presented, for bandwidth generation of the order of 500–1000 nm. Through sign‐alternating dispersion in a CMOS‐compatible silicon nitride waveguide, an efficiency enhancement by factors reaching 2800 is achieved. It is shown that the pulse energy requirement for large‐bandwidth supercontinuum generation at high spectral power (e.g., 1/e level) is lowered from nanojoules to 6 picojoules. The lowered pulse energy requirements enable that chip‐integrated laser sources, such as mode‐locked heterogeneously or hybrid‐integrated diode lasers, can be used as a pump source, enabling fully integrated on‐chip high‐bandwidth supercontinuum sources.
Blue‐Emitting Orthorhombic Boron Nitride Quantum Dots and Quantum‐Dot Light‐Emitting Diodes
Authors: Chen Ping , Yang Shuqi , Liu Fanghai , Jiang Yang , Wang Yule , Huang Ye , Hu Juntao , Chen Lei
Published: January 2023

Quantum‐dot light‐emitting diodes (QLEDs) have been considered the next‐generation display. However, the toxicity of Cd or Pb in these quantum dots (QDs) and the low performance of blue QLEDs remain critical issues, which greatly limit their sustainable development. Herein, first blue‐emitting quantum‐dot light‐emitting diode based on orthorhombic BN QDs with high photoluminescence quantum yield (PLQY) of 31.3% and electroluminescence at 437 nm is reported. With optimal solvothermal parameters, high photoluminescence quantum yield (PLQY) of 31.3% can be realized in the as‐synthesized BN QDs. The turn‐on voltage, maximum luminance, and maximum current density of these novel QLEDs are 9 V, 6.55 Cd m−2, and 34.42 mA cm−2, respectively. This work demonstrates that BN QDs have great potential for blue QLEDs with advantages of being nontoxic, Earth abundant, and having low‐cost manufacturing.
Photostability Improvement of Organic Photodiodes with ZnO Electron Transport Layer
Authors: Wijaya Theodorus Jonathan , Yokota Tomoyuki , Lee Sunghoon , Okano Ryo , Kobayashi Masaki , Someya Takao
Published: January 2023

The stable performance of organic photodiodes (OPDs) is crucial for realizing reliable photosensing and their facile integration into larger systems. However, OPDs with the commonly used ZnO electron transport layer (ETL) suffer from photoinstability, where the dark current increases by several orders of magnitude after light irradiation, thereby affecting the stability of their photodetection. Herein, the increase in the dark current after light irradiation in OPDs with ZnO ETL is suppressed to approximately twice its initial value. This suppression is achieved by improving the quality of the ZnO ETL by increasing the annealing temperature from the widely adopted 180–350 °C. In addition, irradiation with wavelengths longer than 380 nm exhibits a substantially smaller increase in the dark current after light irradiation, by a maximum of 17.6% of those with the sub‐370 nm wavelengths. Furthermore, using X‐ray photoelectron spectroscopy, a decrease in the spectral intensity related to defects in ZnO ETLs annealed at higher temperatures is observed, indicating their role in photoinstability. These findings highlight the importance of defect‐free ETL formation to realize photostable OPDs.
Engineering Multi‐Scale Organization for Biotic and Organic Abiotic Electroactive Systems
Authors: Yao Ze‐Fan , Lundqvist Emil , Kuang Yuyao , Ardoña Herdeline Ann M.
Published: January 2023

Multi‐scale organization of molecular and living components is one of the most critical parameters that regulate charge transport in electroactive systems—whether abiotic, biotic, or hybrid interfaces. In this article, an overview of the current state‐of‐the‐art for controlling molecular order, nanoscale assembly, microstructure domains, and macroscale architectures of electroactive organic interfaces used for biomedical applications is provided. Discussed herein are the leading strategies and challenges to date for engineering the multi‐scale organization of electroactive organic materials, including biomolecule‐based materials, synthetic conjugated molecules, polymers, and their biohybrid analogs. Importantly, this review provides a unique discussion on how the dependence of conduction phenomena on structural organization is observed for electroactive organic materials, as well as for their living counterparts in electrogenic tissues and biotic‐abiotic interfaces. Expansion of fabrication capabilities that enable higher resolution and throughput for the engineering of ordered, patterned, and architecture electroactive systems will significantly impact the future of bioelectronic technologies for medical devices, bioinspired harvesting platforms, and in vitro models of electroactive tissues. In summary, this article presents how ordering at multiple scales is important for modulating transport in both the electroactive organic, abiotic, and living components of bioelectronic systems.
Amorphous Heterostructure Derived from Divalent Manganese Borate for Ultrastable and Ultrafast Aqueous Zinc Ion Storage
Authors: Li Xixian , Ji Chenchen , Shen Jinke , Feng Jianze , Mi Hongyu , Xu Yongtai , Guo Fengjiao , Yan Xingbin
Published: January 2023

Aqueous zinc‐manganese (Zn–Mn) batteries have promising potential in large‐scale energy storage applications since they are highly safe, environment‐friendly, and low‐cost. However, the practicality of Mn‐based materials is plagued by their structural collapse and uncertain energy storage mechanism upon cycling. Herein, this work designs an amorphous manganese borate (a‐MnBOx) material via disordered coordination to alleviate the above issues and improve the electrochemical performance of Zn–Mn batteries. The unique physicochemical characteristic of a‐MnBOx enables the inner a‐MnBOx to serve as a robust framework in the initial energy storage process. Additionally, the amorphous manganese dioxide, amorphous ZnxMnO(OH)2, and Zn4SO4(OH)6·4H2O active components form on the surface of a‐MnBOx during the charge/discharge process. The detailed in situ/ex situ characterization demonstrates that the heterostructure of the inner a‐MnBOx and surface multicomponent phases endows two energy storage modes (Zn2+/H+ intercalation/deintercalation process and reversible conversion mechanism between the ZnxMnO(OH)2 and Zn4SO4(OH)6·4H2O) phases). Therefore, the obtained Zn//a‐MnBOx battery exhibits a high specific capacity of 360.4 mAh g−1, a high energy density of 484.2 Wh kg−1, and impressive cycling stability (97.0% capacity retention after 10 000 cycles). This finding on a‐MnBOx with a dual‐energy storage mechanism provides new opportunities for developing high‐performance aqueous Zn–Mn batteries.
Bilayer Dense‐Porous Li7La3Zr2O12 Membranes for High‐Performance Li‐Garnet Solid‐State Batteries
Authors: Zhang Huanyu , Okur Faruk , Cancellieri Claudia , Jeurgens Lars P. H. , Parrilli Annapaola , Karabay Dogan Tarik , Nesvadba Martin , Hwang Sunhyun , Neels Antonia , Kovalenko Maksym V. , Kravchyk Kostiantyn V.
Published: January 2023

Li dendrites form in Li7La3Zr2O12 (LLZO) solid electrolytes due to intrinsic volume changes of Li and the appearance of voids at the Li metal/LLZO interface. Bilayer dense‐porous LLZO membranes make for a compelling solution of this pertinent challenge in the field of Li‐garnet solid‐state batteries (SSB). Lithium is thus stored in the pores of the LLZO, thereby avoiding i) dynamic changes of the anode volume and ii) the formation of voids during Li stripping due to increased surface area of the Li/LLZO interface. The dense layer then additionally reduces the probability of short circuits during cell charging. In this work, a method for producing such bilayer membranes utilizing sequential tape‐casting of porous and dense layers is reported. The minimum attainable thicknesses are 8–10 µm for dense and 32–35 µm for porous layers, enabling gravimetric and volumetric energy densities of Li‐garnet SSBs of 279 Wh kg−1 and 1003 Wh L−1, respectively. Bilayer LLZO membranes in symmetrical cell configuration exhibit high critical current density up to 6 mA cm−2 and cycling stability of over 160 cycles at a current density of 0.5 mA cm−2 at an areal capacity limitation of 0.25 mAh cm−2.
Ideality Factor Mapping of Back‐Contact Perovskite Solar Cells
Authors: Rietwyk Kevin J. , Lin Xiongfeng , Tan Boer , Warnakula Tharindu , Holzhey Philippe , Zhao Boya , Deng Siqi , Surmiak Maciej A. , Jasieniak Jacek , Bach Udo
Published: January 2023

The efficiency of back‐contact perovskite solar cells has steadily increased over the past few years and now exceeds 11%, with interest in these devices shifting from proof‐of‐concept to viable technology. In order to make further improvements in the efficiency of these devices it is necessary to understand the cause of the low fill factor, low open‐circuit voltage (VOC), and severe hysteresis. Here a time‐dependent Suns‐Voc and Suns‐photoluminescence (PL) analysis are performed to monitor the transient ideality factor spatially. Two sets of quasi‐interdigitated back‐contact perovskite solar cells are studied; cells with and without a mesoporous TiO2 layer. Maps of the PL intensity and ideality factor resemble the periodic structure of the back‐contact electrodes and the transient behavior exhibit distinct features such as a temporary variation in the periodicity of the modulation, spatial phase shifting, and phase offsets. It is shown that the presence of the mesoporous layer greatly reduces recombination, increasing the VOC by 0.12 V. Coupled 2D time‐dependent drift‐diffusion simulations allow the experimental results to be modeled, and replicate the key features observed experimentally. They reveal that non‐uniform ion distribution along the transport layer interfaces can drastically alter the PL intensity and ideality factor throughout the device.
Ultrahigh‐Rate Zn Stripping and Plating by Capacitive Charge Carriers Enrichment Boosting Zn‐Based Energy Storage
Authors: Zhou Yurong , Xia Jiajia , Di Jiangtao , Sun Zhijian , Zhao Liming , Li Linge , Wu Yulong , Dong Lizhong , Wang Xiaona , Li Qingwen
Published: January 2023

Zn metal anodes, the key to aqueous zinc‐based energy storage, are plagued by dendrites and sluggish kinetics, which are closely related to the Zn plating process and restricted charge carriers exchange. Herein, a strategy of charge carriers enrichment during Zn plating by employing zincophilic carbon nanotubes (CNTs) on Zn electrodes for dendrite‐free Zn anodes under ultrahigh current density is reported. The CNTs enable an electric double layer to effectively facilitate the enrichment of charge carriers and the refinement of the electric field distribution at the CNTs–Zn interface, displaying unique advantages in enhancing Zn2+ transfer dynamics and planar Zn deposition. The extra capacitive interfacial process boosts Zn deposition kinetics to afford ultrahigh‐rate Zn plating and stripping by decreasing both electrochemical polarization and concentration polarization. As a consequence, reversible Zn stripping and plating at an ultrahigh current density of 50 mA cm−2 and a remarkable discharging depth of 97% are reached. Zn ion hybrid supercapacitors achieve stable cycling at 50 mA cm−2 for 10 000 cycles. This paper offers mechanistic insight for advanced Zn anodes supporting high‐rate charge/discharge with large capacities and enlightens the design of metal anodes.
Near‐Room‐Temperature Quasi‐Solid‐State F‐Ion Batteries with High Conversion Reversibility Based on Layered Structured Electrolyte
Authors: Yu Yifan , Lei Meng , Li Decheng , Li Chilin
Published: January 2023

Solid‐state fluoride ion batteries (SSFIBs) are anion‐shuttle‐driven and alkali‐metal‐free emerging energy storage systems, and have the advantages of low cost, high safety, and energy density. However, the current major challenges of SSFIBs or quasi‐SSFIBs are the lack of high‐conductivity fluoride electrolytes and the difficulty of mild‐temperature operation of full cells. Here, a 2D fluoride conductor (KSn2F5) synthesized by mechanochemical method is employed as the compatible solid electrolyte with a high F‐ion conductivity of 10−4 S cm−1 at 60 °C. The high concentration and frequent hopping of charge carriers in F‐vacancy‐rich KSn2F5 contribute to the higher ionic conductivity compared to most reported fluoride structures. Integrating this layered electrolyte with high‐voltage CuF2 cathode and Sn/SnF2 anode, a highly reversible cycling of conversion‐type quasi‐SSFIBs with a discharge capacity of 150 mAh g−1 for at least 70 cycles at 60 °C is achieved. The interface engineering aided by tetra‐n‐butylammonium fluoride salt facilitates the F‐ion transfer between cathode and electrolyte and fluorination/defluorination conversion mechanism of CuF2 cathode with optimized multiphase and nanodomain distributions.
Enabling All‐Solid‐State Li Metal Batteries Operated at 30 °C by Molecular Regulation of Polymer Electrolyte
Authors: Wei Ying , Liu Te‐Huan , Zhou Wenjiang , Cheng Hang , Liu Xueting , Kong Jia , Shen Yue , Xu Henghui , Huang Yunhui
Published: January 2023

The low ionic conductivity of poly(ethylene oxide) (PEO)‐based polymer electrolytes at room temperature and the undesired lithium‐dendrite growth at Li|PEO interface impede their further application. Herein, a PEO polymer is regulated at the molecular level through a copper ion (Cu2+) coordination effect with both PEO and Li salts to achieve a high Li+ conductivity of 0.2 mS cm−1 and a transference number of 0.42 at 30 °C. Moreover, the Cu‐coordinated PEO electrolyte is neither sticky nor hygroscopic because the hydrophilic oxygen groups in PEO are terminated by Cu ions. Furthermore, the in situ formed F/Li‐rich inorganic layer induced by CuF2 additive accelerates Li+ transport kinetics and enables uniform Li+ deposition during Li plating/stripping. As a result, the Cu2+‐coordinated PEO electrolytes deliver a high critical current density of 1.5 mA cm−2 at 30 °C. An all‐solid‐state Li‐LiNi0.83Co0.12Mn0.05O2 (NCM83) battery with such a copper coordinated PEO electrolyte exhibits a long cycle life over 500 cycles with a capacity retention of 71% under 0.6 C at 30 °C. When the mass loading increases to a record high of 7 mg cm−2, the Li‐NCM83 cell delivers a high areal capacity of 1.07 mAh cm−2 under 0.1 C at 30 °C.
Bistable, Pneumatically Actuated Microgripper Fabricated Using Two‐Photon Polymerization and Oxygen Plasma Etching
Authors: Power Maura , Barbot Antoine , Seichepine Florent , Yang Guang-Zhong
Published: January 2023

Fabrication of actuatable micromechanisms onto the tip of submillimeter medical instruments permits microsurgery, cellular‐level intervention, targeted drug delivery, or placement of microimplants. In these systems, a common lack of integrated microsensors or optical feedback prohibits stabilizing closed‐loop control. Moreover, the low stiffness of compact actuator and microfabrication limitations lead to difficult control. Herein, a compact bistable open‐loop micromechanism mounted on a small (170 μm) capillary fiber is developed. Bistabillity is utilized to control the mechanism to precise positions without the need for feedback or continuous control. Repeatable fabrication of this compact and high‐resolution bistable micromechanism is achieved with a two‐photon polymerization (2PP) process refined by oxygen plasma etching (OPE) that results in minimal feature size of a few hundred nanometers along the direction of the laser's axis, allowing 2PP bistable mechanisms to be fabricated in arbitrary orientations not restricted by printing direction. Finite element method simulations and experimental studies of the OPE effect are presented and used to optimize the micromechanism's bistable behavior. Finally, the feasibility of such compact bistable mechanism with a gripper that captures 50 μm spheres and passively maintains grasping without constant driving force even in long open‐close cycles is demonstrated.
Directionally Compliant Legs Enabling Crevasse Traversal in Small Ground‐Based Robots
Authors: Lathrop Emily , Tolley Michael T. , Gravish Nick
Published: January 2023

Small ground‐based robots show promise for locomotion on complex surfaces. A critical application area for such robots is movement over complex terrain and within constricted space such as narrow gaps in rubble. To contend with this terrain complexity, robots typically require high degree‐of‐freedom (DOF) limbs. However, for small robot platforms, this approach of high DOF legs is impractical due to actuator limitations. This presents an opportunity to design robots whose morphology enables the outsourcing of computational tasks to the robot body through the use of compliant elements (morphological computation). Herein, a novel robot appendage is developed that can passively compress in a programmed direction in response to environmental constrictions. A robot equipped with these appendages can enter narrow spaces down to 72% of the robot's sprawled body width as well as low ceilings down to 68% its freestanding height. The robot is able to step onto and over small terrain features ( hip height) and navigate various natural terrain types with ease. The results show that these compressible appendages enable versatile robot locomotion for robot exploration in previously unmapped environments.
Design of 3D Magnetic Tactile Sensors with High Sensing Accuracy Guided by the Theoretical Model
Authors: Hu Xiaocheng , Zhu Heng , Chen Ruiwen , Hu Sideng , Jia Zheng , Yu Honghui , Qu Shaoxing
Published: January 2023

The past decade has witnessed a surging interest in the study of magnetic tactile sensors that can detect subtle changes in both normal and shear forces. However, due to the lack of guidance by appropriate theoretical models, the development of previous magnetic tactile sensors relies either on a trial‐and‐error manner or tedious point‐by‐point experimental calibrations, which are costly and time‐inefficient. Here, a theoretical model integrating magnetics, artificial neural networks, and nonlinear solid mechanics is proposed for the first time to guide the design of 3D magnetic tactile sensors. Then, a button‐shaped magnetic tactile sensor prototype that can detect subtle triaxial force changes is fabricated, which relates the nonlinear magnetic flux density to the external force, without burdensome calibration procedures. The sensor can achieve an axial measurement error of less than 1% and an in‐plane error of less than 3.7% with excellent durability. This study provides a comprehensive understanding of magnetic tactile sensors and sheds light on their applications in soft robotics, intelligent manipulation, and human–robot interaction (HRI).
Harnessing Nonuniform Pressure Distributions in Soft Robotic Actuators
Authors: Matia Yoav , Kaiser Gregory H. , Shepherd Robert F. , Gat Amir D. , Lazarus Nathan , Petersen Kirstin H.
Published: January 2023

Herein, complex motion in soft, fluid‐driven actuators composed of elastomer bladders arranged around a neutral plane and connected by slender tubes is demonstrated. Rather than relying on complex feedback control or multiple inputs, the motion is generated with a single pressure input, leveraging viscous flows within the actuator to produce nonuniform pressure between bladders. Using an accurate predictive model coupling with a large deformation Cosserat rod model and low‐Reynolds‐number flow, all dominating dynamic interactions including extension and curvature are captured with two governing equations. Given insights from this model, five design elements are described and demonstrated in practice. By choosing the relative timescales between the solid, fluid, and input pressure cycles, the tip of the actuator can obtain almost any desired trajectory and can be placed anywhere temporarily within its 2D workspace. Finally, the benefits of viscous‐driven soft actuators are showcased in a six‐legged untethered robot able to walk 0.05 body lengths per second. The foundation is laid for a new class of morphologically intelligent, soft robotic actuators that enables complex deformations and multifunctionality without explicit drivers; whereby generating nonuniform pressure distributions, their infinite degrees of freedom can be exploited.
Exploring the Evolution of Metal Halide Perovskites via Latent Representations of the Photoluminescent Spectra
Authors: Sanchez Sheryl , Liu Yongtao , Yang Jonghee , Kalinin Sergei V. , Ziatdinov Maxim , Ahmadi Mahshid
Published: January 2023

In the last several years, laboratory automation and high‐throughput synthesis and characterization have come to the forefront of the research community. The large datasets require suitable machine learning techniques to analyze the data effectively and extract the properties of the system. Herein, the binary library of metal halide perovskite (MHP) microcrystals, MAxFA1−xPbI3−xBrx, is explored via low‐dimensional latent representations of composition‐ and time‐dependent photoluminescence (PL) spectra. The variational autoencoder (VAE) approach is used to discover the latent factors of variability in the system. The variability of the PL is predominantly controlled by compositional dependence of the bandgap. At the same time, secondary factor of variability includes the phase separation associated with the formation of the double peaks. To overcome the interpretability limitations of standard VAEs, the workflow based on the translationally invariant variational (tVAEs) and conditional autoencoders (cVAEs) is introduced. tVAE discovers known factors of variation within the data, for example, the (unknown) shift of the peak due to the bandgap variation. Conversely, cVAEs impose known factor of variation, in this case anticipated bandgap. Jointly, the tVAE and cVAE allow to disentangle the underlying mechanisms present within the data that bring a deeper meaning and understanding within MHP systems.
Efficient Method for Error Detection and Correction in In‐Memory Computing Based on Reliable Ex‐Logic Gates
Authors: Park Taegyun , Kim Yeong Rok , Shin Dong Hoon , Lee Byeol Jun , Hwang Cheol Seong
Published: January 2023

In‐memory computing using memristor‐based stateful logic reveals high efficiency in the computing paradigm where the memory and computation are colocated. Still, variations in the memristor induce reliability issues for practical applications. Previous error detection and correction modules in the inmemory logic gates can handle the errors but only account for nonswitching errors of the output memristor, while the highly probable switching error of the output memristor is neglected, reducing overall efficiency. Moreover, the module operations use other added stateful logic gates, which may add errors. Herein, modules to handle both nonswitching and switching error cases within the three average steps using reliable logic gates consisting of five memristors are proposed. Detecting both error cases allows logic gates to be still operated in the optimized region for high‐energy efficiency and stability. In addition, combining two different logic families of stateful and sequential logic gates provides the reliability of the stateful logic gates and a possible solution to the peripheral complexity of cascading sequential logic gates. Although detection and correction are demonstrated in NOR and NAND logic gates with the memristor model, the other logic gates can be applied with the same algorithm with the appropriate module‐enable signal and input‐checker bits.
Highly Sensitive Strain Sensor Based on Microfiber Coupler for Wearable Photonics Healthcare
Authors: Wang Xin , Zhou Hongyou , Chen Meihua , He Yongcheng , Zhang Zhishen , Gan Jiulin , Yang Zhongmin
Published: January 2023

Flexible strain sensors are essential components of wearable smart devices that perceive and respond to strain stimulations. However, the sensitivity and response time of most sensors require further improvement to detect subtle strains related to human bodies. Herein, an ultrasensitive flexible optical sensor with fast response time has been built based on a microfiber coupler encapsulated in polydimethylsiloxane. Benefiting from dramatic change of coupling ratio of the microfiber coupler under weak strain, this flexible strain sensor exhibits ultrahigh strain sensitivity (gauge factor, GF = 900), low detection limit (0.001%), ultrafast response time (<0.167 ms), wide sensing range (0.45%), and superior durability and stability (>10 000 cycles). Real‐time capturing and recognizing of respiration, broadband sound signals, and pulse waves at different sites of human body have been demonstrated based on this highly sensitive microfiber coupler sensor. Moreover, simultaneous detection of the wrist pulse and human voice has been achieved based on the frequency division multiplexing technology. This flexible photonics strain sensor could serve as the prototype of ultrasensitive flexible optical sensors with fast response time for the development of high performance and wearable healthcare devices.
Optimization of Random Telegraph Noise Characteristics in Memristor for True Random Number Generator
Authors: Song Min Suk , Kim Tae-Hyeon , Hwang Hwiho , Ahn Suhyeon , Nili Hussein , Kim Hyungjin
Published: January 2023

Memristor devices can be utilized for various computing applications, and stochastic computing is one of them. The intrinsic stochastic characteristics of the memristor cause unpredictable current fluctuations by the capture and emission of electrons in a trap site. Herein, a true random number generator (TRNG) using the random telegraph noise (RTN) of the memristor as an entropy source is proposed. TiOx/Al2O3memristors are fabricated, and the capture time probability of the RTN characteristics is modulated to 50% with varying read‐voltage and device conductance state. In addition, the TRNG operations with the RTN current signals as entropy sources are experimentally demonstrated with a customized breadboard, and the randomness is verified with the National Institute of Standards and Technology (NIST) tests.
Mechanical System with Soft Modules and Rigid Frames Realizing Logic Gates and Computation
Authors: Zhang Yubo , Qian Zheng , Zhuang Juncheng , Fan Siping , Wei Huaxian , Yang Nan
Published: January 2023

Mechanical computation outperforms electrical computation in applications under extreme conditions. Currently, logic gates can be constructed with mechanical metamaterials, but this may require complex architectures and computing rules, and more complex computations based on these gates are considerably more challenging. Mechanical computing systems with multistability cannot return to their initial stable states, which are hardly reused. Moreover, providing digital electrical outputs is useful to communicate with electrical systems. To address these issues, mechanical metamaterials can be integrated in a manner that is similar to a circuit network with a powerful computing capability. Herein, a general method that combines soft convex and concave modules, rigid frames, and conductive materials in one system to realize logic gates, addition, and multiplication is proposed. The soft modules make or break electrical connections with adjacent frames due to the presence or absence of compressive forces, operating as open and closed switches. Connections and disconnections between modules and frames can be demonstrated with conductive materials and LEDs. The proposed mechanism is simple, versatile, and reusable, allowing soft mechanical metamaterial units to carry out complex computations. The approach may improve the capabilities of soft robots, robotic materials, and microelectromechanical systems.
Biorobotic Waterfowl Flipper with Skeletal Skins in a Computational Framework: Kinematic Conformation and Hydrodynamic Analysis
Authors: Huang Jinguo , Wang Tianmiao , Liang Jianhong , Yang Xingbang , Wang Haodong , Kang Guixia
Published: January 2023

Cormorants (Phalacrocoraxe), types of aquatic birds, utilize the compliance/flexibility of the flippers and exploit hydrodynamic/biomechanic processes to accomplish diverse operations. Particularly, the flipper‐propelled locomotion exhibits traits such as super‐redundancy and large deformations, necessitating depiction of both movements of the rigid skeletons as well as local deformations of the soft tissues. However, there are few well‐established kinematic/hydrodynamic framework models and constitutive equations for such rigid–flexible intrinsically coupled biosystems. Herein, combined with a skeletal skinning algorithm to handle the deformation of a flexible body attached to a rigid body, a numerical computation framework for an in‐depth fluid–structure interaction is presented, which enables the capture of viscoelastic and anisotropic characteristics of a highly compliant 3D rigid–flexible coupled model in a low‐Reynolds‐number flow. Considering the biorobotic cormorant flipper with a nonuniformly distributed stiffness as a representative, the challenging issue of controlling a biomechanically compliant flipper to synthesize realistic locomotion sequences, including rigid skeleton movements and soft tissue deformations, is addressed. Furthermore, a numerical computational hydrodynamic analysis is performed to demonstrate that the cormorant flipper can generate 5 N fluid force and 0.45 N m fluid moment during the turning operation in 0.8 s, which is consistent with the former experimental results.
Untethered Flight of a 270 mg Microrobot Powered by Onboard Energy
Authors: Yun RuiDe , Zhang LingYue , Zhu YangSheng , Zhang HengYu , Zhan WenCheng , Liu ZhiWei , Yan XiaoJun , Qi MingJing
Published: January 2023

It is challenging for microrobots to fly using onboard energy due to the relatively heavy power supplies and inefficient actuators that are limited to a small size (mass less than 1000 mg and wingspan less than 100 mm). Inspired by the movement of jellyfish in nature (Physophora hydrostatica), herein, a microscale aerial vehicle FlyJelly is introduced, powered by onboard energy to achieve untethered flight. FlyJelly uses a balloon filled with helium to overcome self‐gravity and an actuator powered by electrostatic power to generate thrust. The balloon, heat sealed with two gold‐covered Mylar films, weighs 95.56 mg, provides 257.9 mg of buoyancy when filled with helium, and stores 19.457 × 10−3 J of energy when powered by 2400 V of direct current. The electrostatic actuator is composed of multiflapping units arranged radially and symmetrically, consuming only 0.3370 mW of power but generating a thrust of 0.2271 mN to drive the vehicle for flight. Benefiting from a design of distributed propulsion, FlyJelly is highly reliable and continues to work well even after the actuator is damaged. The milligram‐level weight, untethered flight with onboard energy, and high reliability make the prototype suitable for development as a long‐term remote exploration and search‐and‐rescue mission.