Yang Wang

Colloidal quantum dots composed of mercury telluride (HgTe) have emerged as promising materials for infrared detection systems, imaging applications, focal plane array technologies, and various other optoelectronic platforms. These nanomaterials exhibit a distinctive bandgap that can be controlled through particle size manipulation, covering wavelengths from the near‐infrared through terahertz regions, and demonstrate robust charge carrier transport characteristics that position them favorably for advanced infrared technological applications. This review consolidates current developments in HgTe CQD fabrication methods, their electronic band structures, and integration strategies for functional devices. The nanoscale dimensions of HgTe induce quantum confinement phenomena that enable precise bandgap engineering, transitioning from negative to positive energy gaps and facilitating tunable light absorption and emission across an extensive wavelength spectrum. We analyze how variations in nanoparticle dimensions, morphology, and surface functionalization impact their optical behavior and electrical transport characteristics. Additionally, we explore the implementation of HgTe CQDs in photodetection platforms, field‐effect transistor configurations, and imaging array architectures, emphasizing design strategies, operational characteristics, and durability limitations. This comprehensive survey seeks to advance understanding of HgTe CQD systems and facilitate their continued evolution toward commercially viable, cost‐effective, and high‐efficiency infrared optoelectronic solutions.

In this work, we designed and evaluated 2D pentagonal MgX ₂ (X = O, S, Se, Te) monolayers via first-principles calculations. These materials show promise as bifunctional photocatalysts for overall water splitting and selective CO ₂ reduction.

Flexible skin electronics are increasingly sought after for their potential in sensing and drug delivery within wearable human–machine interfaces. However, developing multifunctional applications that maintain biocompatibility and stable electrical performance under various mechanical deformations remains a challenge. Here, we introduce tattoo paper-based graphene–gold conductors that are approximately 0.04 mm thick and feature a dual conductive pathway within the graphene–gold film. By integrating a folding structure with this dual conductive pathway, we can mitigate the strain effects on the electrical resistance of film-based conductors, resulting in wider areas of stable resistance. In addition, we have designed film conductors with a kirigami structure, which achieves a high initial conductivity of 1.5 × 10³ S cm⁻¹ and exhibits negligible resistance changes across a broad strain range of 0 to 130%. We utilize these conductors to develop waterproof on-skin patches that incorporate electrically and optically active heaters for body heating and drug delivery. Furthermore, we have created an on-skin dialing interface using these conductors, which enables users to make telephone calls based on triboelectric nanogenerators.

The human skin possesses the capability to detect thermal and mechanical stimuli simultaneously. Ingenious flexible sensors have been explored to mimic such functionalities by integrating multiple sensing elements or adopting multimodal sensing principles. However, the widespread application of these sensors has faced obstacles such as complicated manufacturing processes, signal mismatches between different components, and high power consumption. Here, we report a single-mode self-powered flexible sensor capable of simultaneously detecting both temperature and pressure stimuli through the seamless integration of complementary and compatible thermoelectric and triboelectric sensing mechanisms. The resulting hybrid thermoelectric-triboelectric sensor exhibits unique features that are difficult to achieve with existing approaches, including single-mode output (voltage signal only), significantly simplified operation (single-measurement device), ultralow power consumption, adaptive response behavior, and excellent discriminative capability for complex stimuli. Additionally, a deep learning regression model has been implemented to dispose of the single-mode signals, achieving an impressive accuracy of 94.7% in distinguishing contact objects. This work presents an innovative design that substantially simplifies both fabrication and operation while simultaneously enhancing the functionality and energy efficiency of next-generation flexible sensing systems.

Tactile sensing, especially pressure and temperature recognition, is crucial for both humans and robots in identifying objects. The general solutions, which use piezoresistive, capacitive, and thermal resistance effects, are usually subject to single-mode sensing and an energy supply. Here, we propose a multimode self-powered sensor. The sensor can respond to pressure and temperature stimuli using triboelectric and thermoelectric effects. Furthermore, we developed a sensing system comprising sensors, a deep learning block, and a smart board. The deep learning model can fuse features of triboelectric and thermoelectric signals, enabling a high accuracy of 99.8% in recognizing ten objects. This method may provide the future design of self-powered sensors for object recognition in robotics.

Humans can grab and identify objects by capturing the features of physical shape, temperature, and material. However, creating artificial sensors with finger‐like tactile capabilities is challenging due to the contradiction between structural compliance and multifunctional sensing. Here, a sensory system for a robot hand that can achieve object recognition is reported. The sensor with a simple horizontal sensing structure can respond to strain, material, and temperature stimuli using piezoresistive, triboelectric, and thermoelectric effects. A machine learning algorithm to train and classify tactile sensing signals, enabling a high accuracy of 98.5% in recognizing five objects is also developed. This work contributes to the development of sensory systems for object recognition in soft robotics.

Layered semiconductors of the V-VI group have attracted considerable attention in optoelectronic applications owing to their atomically thin structures. They offer thickness-dependent optical and electronic properties, promising ultrafast response time, and high sensitivity. Compared to the bulk, 2D bismuth selenide (Bi₂Se₃) is recently considered a highly promising material. In this study, 2D nanosheets are synthesized by prolonged sonication in two different solvents, such as N-methyl-2-pyrrolidone (NMP) and chitosan-acetic acid solution (CS-HAc), using the liquid-phase exfoliation (LPE) method. X-ray diffraction confirms the amorphous nature of exfoliated 2D nanosheets with maximum peak intensity at the same position (015) crystal plane as that obtained in its bulk counterpart. SEM confirms the thin 2D nanosheet-like morphology. Successful exfoliation of Bi₂Se₃ nanosheets up to five layers is achieved using CS-HAc solvent. The as-synthesized 2D nanosheets in different solvents are employed to fabricate the photodetector. At minimum selected power density, the photodetector fabricated using exfoliated ultrathin 2D nanosheets exhibits the highest range of responsivity, varying from 15 to 2.5 mA/W, and detectivity ranging from 2.83 × 10⁹ to 6.37 × 10⁷. Ultrathin 2D Bi₂Se₃ nanosheets have fast rise and fall times, ranging from 0.01 to 0.12 and 0.01 to 0.06 s, respectively, at different wavelengths. Ultrathin Bi₂Se₃ nanosheets have improved photodetection parameters as compared to multilayered nanosheets due to the high surface to volume ratio, reduced recombination and trapping of charge carrier, improved carrier confinement, and faster carrier transport due to the thin layer.

Wearable electronics have received extensive attention in human–machine interactions, robotics, and health monitoring. The use of multifunctional sensors that are capable of measuring a variety of mechanical or environmental stimuli can provide new functionalities for wearable electronics. Advancements in material science and system integration technologies have contributed to the development of high-performance flexible multifunctional sensors. This review presents the main approaches, based on functional materials and device structures, to improve sensing parameters, including linearity, detection range, and sensitivity to various stimuli. The details of electrical, biocompatible, and mechanical properties of self-powered sensors and wearable wireless systems are systematically elaborated. Finally, the current challenges and future developmental directions are discussed to offer a guide to fabricate advanced multifunctional sensors.