Molecular-Scale Geometric Design: Zigzag-Structured Intrinsically Stretchable Polymer Semiconductors.

Orienting intelligence and multifunction, stretchable semiconductors are of great significance in constructing next-generation human-friendly wearable electronic devices. Nevertheless, rendering semiconducting polymers mechanical stretchability without compromising intrinsic electrical performance remains a major challenge. Combining geometry-innovated inorganic systems and structure-tailored organic semiconductors, a molecular-scale geometric design strategy is proposed to obtain high-performance intrinsically stretchable polymer semiconductors.

Halogenated-edge polymeric semiconductor for efficient spin transport.

Organic semiconductors (OSCs) are featured by weak spin-orbit coupling due to their light chemical element composition, which enables them to maintain spin orientation for a long spin lifetime and show significant potential in room-temperature spin transport. Carrier mobility and spin lifetime are the two main factors of the spin transport performance of OSCs, however, their ambiguous mechanisms with molecular structure make the development of spintronic materials really stagnant. Herein, the effects of halogen substitution in bay-annulated indigo-based polymers on carrier mobility and spin relaxation have been systematically investigated.

Strain-insensitive viscoelastic perovskite film for intrinsically stretchable neuromorphic vision-adaptive transistors.

Stretchable neuromorphic optoelectronics present tantalizing opportunities for intelligent vision applications that necessitate high spatial resolution and multimodal interaction. Existing neuromorphic devices are either stretchable but not reconcilable with multifunctionality, or discrete but with low-end neurological function and limited flexibility. Herein, we propose a defect-tunable viscoelastic perovskite film that is assembled into strain-insensitive quasi-continuous microsphere morphologies for intrinsically stretchable neuromorphic vision-adaptive transistors.

A detachable interface for stable low-voltage stretchable transistor arrays and high-resolution X-ray imaging.

Challenges associated with stretchable optoelectronic devices, such as pixel size, power consumption and stability, severely brock their realization in high-resolution digital imaging. Herein, we develop a universal detachable interface technique that allows uniform, damage-free and reproducible integration of micropatterned stretchable electrodes for pixel-dense intrinsically stretchable organic transistor arrays. Benefiting from the ideal heterocontact and short channel length (2 μm) in our transistors, switching current ratio exceeding 10, device density of 41,000 transistors/cm, operational voltage down to 5 V and excellent stability are simultaneously achieved.

Biomimetic nanocluster photoreceptors for adaptative circular polarization vision.

Nanoclusters with atomically precise structures and discrete energy levels are considered as nanoscale semiconductors for artificial intelligence. However, nanocluster electronic engineering and optoelectronic behavior have remained obscure and unexplored. Hence, we create nanocluster photoreceptors inspired by mantis shrimp visual systems to satisfy the needs of compact but multi-task vision hardware and explore the photo-induced electronic transport.

Photoinduced Nonvolatile Memory Transistor Based on Lead-Free Perovskite Incorporating Fused π-Conjugated Organic Ligands.

Perovskites field-effect transistors (PeFETs) have been intensively investigated for their application in detector and synapse. However, synapse based on PeFETs is still very difficult to integrate excellent charge carrier transporting ability, photosensitivity, and nonvolatile memory effects into one device, which is very important for developing bionic electronic devices and edge computing. Here, two-dimensional (2D) perovskites are synthesized by incorporating fused π-conjugated pyrene-O-ethyl-ammonium (POE) ligands and a systematic study is conducted to obtain enhanced performance and reliable PeFETs.

Molecular Design of Multifunctional Integrated Polymer Semiconductors with Intrinsic Stretchability, High Mobility, and Intense Luminescence.

Multifunctional semiconductors integrating unique optical, electrical, mechanical, and chemical characteristics are critical to advanced and emerging manufacturing technologies. However, due to the trade-off challenges in design principles, fabrication difficulty, defects in existing materials, etc., realizing multiple functions through multistage manufacturing is quite taxing.

Van der Waals Multilayer Heterojunction for Low-Voltage Organic RGB Area-Emitting Transistor Array.

Organic light-emitting transistors (OLETs) have garnered considerable attention from academy and industry due to their potential applications in next-generation display technologies, multifunctional devices, and organic electrically pumped lasers. However, overcoming the trade-offs among power consumption, external quantum efficiency (EQE), and uniform area emission remains a long-standing issue for OLETs. Herein, a van der Waals multilayer heterojunction methodology is proposed to enhance the layer-to-layer interfacial interaction and contact, resulting in better dipole shielding, carrier transport, exciton recombination, and current density distribution.

A Self-Assembled 3D Penetrating Nanonetwork for High-Performance Intrinsically Stretchable Polymer Light-Emitting Diodes.

The emergence of wearable technology can significantly benefit from electronic displays fabricated using intrinsically stretchable (is-) materials. Typically, an improvement in the stretchability of conventional light-emitting polymers is accompanied by a decrease in charge transportability, thus resulting in a significant decrease in device efficiency. In this study, a self-assembled 3D penetrating nanonetwork is developed to achieve increased stretchability and mobility simultaneously, based on high-molecular-weight phenylenevinylene (L-SY-PPV) and polyacrylonitrile (PAN).

Optimization design of a Lamb wave device for density sensing of nonviscous liquid.

A Lamb wave device composed of a piezoelectric plate loaded with a nonviscous liquid layer is presented. The relation between the Lamb wave phase velocity and the liquid density can be used for liquid density sensing. In this paper, utilizing the partial wave theory, the concept of effective permittivity is introduced to analyze the Lamb wave's excitation and the phase velocity calculation under a certain liquid density.

Evaluating sensor reliability in classification problems based on evidence theory.

This paper presents a new framework for sensor reliability evaluation in classification problems based on evidence theory (or the Dempster-Shafer theory of belief functions). The evaluation is treated as a two-stage training process. First, the authors assess the static reliability from a training set by comparing the sensor classification readings with the actual values of data, which are both represented by belief functions.

Investigation on SAW properties of LGS and optimal cuts for high-temperature applications.

A promising perspective for surface acoustic wave (SAW) device applications at high temperature has been opened by langasite (LGS). The SAW properties of LGS in singly and doubly rotated cuts at 250 degrees C are investigated. Three noticeable regions for SAW-cut orientations and propagation directions at high temperature are put forward and are defined by Euler angles [0 degrees, 20 degrees --> 50 degrees, 35 degrees --> 45 degrees], [0 degrees, 85 degrees --> 110 degrees, 0 degrees --> 5 degrees], and [0 degrees, 138 degrees --> 145 degrees, 20 degrees --> 23 degrees], respectively.

Eigenvalue and field equations of three-layered uniaxial fibers and their applications to the characteristics of long-period fiber gratings with applied axial strain.

By using the Debye potentials, the exact eigenvalue equations and the corresponding field distributions of the core and cladding modes for three-layered, radially stratified, and dielectric uniaxial optical fibers are derived completely; the modes include TE, TM, and hybrid HE/EH modes. The strain characteristics of long-period fiber gratings' (LPFGs') with applied axial strain are investigated theoretically by studying three-layered uniaxial optical fibers. When uniform axial strain is applied to fiber, the core, and inner and outer cladding become uniaxial crystal optically; that is, the optical axes are parallel to the fiber's axis.

[Sensing scheme of minim liquid density based on Lamb-wave].

This paper presents and discusses the liquid density sensing potential of a delay line Lamb-wave sensor configuration, where Lamb wave is excited only by interdigital transducer (IDT), without membrane when fabricated. An optimized cut orientation and the normalized thickness of substrate by using genetic algorithm is presented to improve the sensitivity of the sensor and to get low noise. Experimental measurements performed on Lamb-wave device fabricated from Y-Z LiNbO3 in a delay line configuration are found to be in agreement with theoretical calculations.