Investigation of Donor-like State Distributions in Solution-Processed IZO Thin-Film Transistor through Photocurrent Analysis.

The density of donor-like state distributions in solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs) is thoroughly analyzed using photon energy irradiation. This study focuses on quantitatively calculating the distribution of density of states (DOS) in IZO semiconductors, with a specific emphasis on their variation with indium concentration. Two calculation methods, namely photoexcited charge collection spectroscopy (PECCS) and photocurrent-induced DOS spectroscopy (PIDS), are employed to estimate the density of the donor-like states.

Analyzing Acceptor-like State Distribution of Solution-Processed Indium-Zinc-Oxide Semiconductor Depending on the In Concentration.

Understanding the density of state (DOS) distribution in solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs) is crucial for addressing electrical instability. This paper presents quantitative calculations of the acceptor-like state distribution of solution-processed IZO TFTs using thermal energy analysis. To extract the acceptor-like state distribution, the electrical characteristics of IZO TFTs with various In molarity ratios were analyzed with respect to temperature.

Flexible biomimetic block copolymer composite for temperature and long-wave infrared sensing.

Biological compounds often provide clues to advance material designs. Replicating their molecular structure and functional motifs in artificial materials offers a blueprint for unprecedented functionalities. Here, we report a flexible biomimetic thermal sensing (BTS) polymer that is designed to emulate the ion transport dynamics of a plant cell wall component, pectin.

Silent Speech Recognition with Strain Sensors and Deep Learning Analysis of Directional Facial Muscle Movement.

Silent communication based on biosignals from facial muscle requires accurate detection of its directional movement and thus optimally positioning minimum numbers of sensors for higher accuracy of speech recognition with a minimal person-to-person variation. So far, previous approaches based on electromyogram or pressure sensors are ineffective in detecting the directional movement of facial muscles. Therefore, in this study, high-performance strain sensors are used for separately detecting - and -axis strain.

Stretchable PPG sensor with light polarization for physical activity-permissible monitoring.

Skin-attachable sensors, which represent the ultimate form of wearable electronic devices that ensure conformal contact with skin, suffer from motion artifact limitations owing to relative changes in position between the sensor and skin during physical activities. In this study, a polarization-selective structure of a skin-conformable photoplethysmographic (PPG) sensor was developed to decrease the amount of scattered light from the epidermis, which is the main cause of motion artifacts. The motion artifacts were suppressed more than 10-fold in comparison with those of rigid sensors.

A Design Strategy for Intrinsically Stretchable High-Performance Polymer Semiconductors: Incorporating Conjugated Rigid Fused-Rings with Bulky Side Groups.

Strategies to improve stretchability of polymer semiconductors, such as introducing flexible conjugation-breakers or adding flexible blocks, usually result in degraded electrical properties. In this work, we propose a concept to address this limitation, by introducing conjugated rigid fused-rings with optimized bulky side groups and maintaining a conjugated polymer backbone. Specifically, we investigated two classes of rigid fused-ring systems, namely, benzene-substituted dibenzothiopheno[6,5-:6',5'-]thieno[3,2-]thiophene (Ph-DBTTT) and indacenodithiophene (IDT) systems, and identified molecules displaying optimized electrical and mechanical properties.

A design strategy for high mobility stretchable polymer semiconductors.

As a key component in stretchable electronics, semiconducting polymers have been widely studied. However, it remains challenging to achieve stretchable semiconducting polymers with high mobility and mechanical reversibility against repeated mechanical stress. Here, we report a simple and universal strategy to realize intrinsically stretchable semiconducting polymers with controlled multi-scale ordering to address this challenge.

Standalone real-time health monitoring patch based on a stretchable organic optoelectronic system.

Skin-like health care patches (SHPs) are next-generation health care gadgets that will enable seamless monitoring of biological signals in daily life. Skin-conformable sensors and a stretchable display are critical for the development of standalone SHPs that provide real-time information while alleviating privacy concerns related to wireless data transmission. However, the production of stretchable wearable displays with sufficient pixels to display this information remains challenging.

In-Depth Investigation of the Correlation between Organic Semiconductor Orientation and Energy-Level Alignment Using In Situ Photoelectron Spectroscopy.

Organic semiconductors (OSCs) are of interest for replacing traditional Si-based semiconductors as their flexibility and transparency enable new applications. The properties of OSC materials greatly depend on their orientation and molecular arrangement, which are strongly dependent on the underlying substrate material. Hence, in this study, in situ ultraviolet photoelectron spectroscopy (UPS) is used to elucidate the effect of the substrate on OSC orientation.

Fully stretchable active-matrix organic light-emitting electrochemical cell array.

Intrinsically and fully stretchable active-matrix-driven displays are an important element to skin electronics that can be applied to many emerging fields, such as wearable electronics, consumer electronics and biomedical devices. Here, we show for the first time a fully stretchable active-matrix-driven organic light-emitting electrochemical cell array. Briefly, it is comprised of a stretchable light-emitting electrochemical cell array driven by a solution-processed, vertically integrated stretchable organic thin-film transistor active-matrix, which is enabled by the development of chemically-orthogonal and intrinsically stretchable dielectric materials.

Electrochemical Properties of High Nickel Content Li(NiCoMn)O₂ with an Alumina Thin-Coating Layer as a Cathode Material for Lithium Ion Batteries.

The cathode material, high Nickel content NiCoMn (NCM), was synthesized by coprecipitation with NH₄OH used as a complexing agent. The prepared materials are made in the formation of spherical particles of Li(NiCoMn)O₂ of several micrometers in diameter. Al₂O₃ was coated by an impregnation method and its content was gradually increased to 1, 2 and 5 wt%.

Stretchable self-healable semiconducting polymer film for active-matrix strain-sensing array.

Skin-like sensory devices should be stretchable and self-healable to meet the demands for future electronic skin applications. Despite recent notable advances in skin-inspired electronic materials, it remains challenging to confer these desired functionalities to an active semiconductor. Here, we report a strain-sensitive, stretchable, and autonomously self-healable semiconducting film achieved through blending of a polymer semiconductor and a self-healable elastomer, both of which are dynamically cross-linked by metal coordination.

Conjugated Carbon Cyclic Nanorings as Additives for Intrinsically Stretchable Semiconducting Polymers.

Molecular additives are often used to enhance dynamic motion of polymeric chains, which subsequently alter the functional and physical properties of polymers. However, controlling the chain dynamics of semiconducting polymer thin films and understanding the fundamental mechanisms of such changes is a new area of research. Here, cycloparaphenylenes (CPPs) are used as conjugated molecular additives to tune the dynamic behaviors of diketopyrrolopyrrole-based (DPP-based) semiconducting polymers.

An integrated self-healable electronic skin system fabricated via dynamic reconstruction of a nanostructured conducting network.

Electronic skin devices capable of monitoring physiological signals and displaying feedback information through closed-loop communication between the user and electronics are being considered for next-generation wearables and the 'Internet of Things'. Such devices need to be ultrathin to achieve seamless and conformal contact with the human body, to accommodate strains from repeated movement and to be comfortable to wear. Recently, self-healing chemistry has driven important advances in deformable and reconfigurable electronics, particularly with self-healable electrodes as the key enabler.

Skin electronics from scalable fabrication of an intrinsically stretchable transistor array.

Skin-like electronics that can adhere seamlessly to human skin or within the body are highly desirable for applications such as health monitoring, medical treatment, medical implants and biological studies, and for technologies that include human-machine interfaces, soft robotics and augmented reality. Rendering such electronics soft and stretchable-like human skin-would make them more comfortable to wear, and, through increased contact area, would greatly enhance the fidelity of signals acquired from the skin. Structural engineering of rigid inorganic and organic devices has enabled circuit-level stretchability, but this requires sophisticated fabrication techniques and usually suffers from reduced densities of devices within an array.

Thiophene-Thiazole-Based Semiconducting Copolymers for High-Performance Polymer Field-Effect Transistors.

We report a newly synthesized donor (D)-acceptor (A)type semiconducting copolymer, consisting of thiophene as an electron-donating unit and thiazole as an electron-accepting unit (PQTBTz-TT-C8) for the active layer of the organic field-effect transistors (OFETs). Specifically, this study investigates the structure and electrical property relationships of PQTBTz-TT-C8 with comprehensive analyses on the charge-transporting properties corresponding to the spin rate of the spin coater during the formation of the PQTBTz-TT-C8 film. The crystallinity of PQTBTz-TT-C8 films is examined with grazing incidence X-ray diffraction.